000100291012/312026Q3false000010082612/312026Q3false000001865412/312026Q3falsehttp://fasb.org/us-gaap/2026#UsTreasuryUstInterestRateMember11.365http://xbrl.sec.gov/country/2026#US413P467Dxbrli:sharesiso4217:USDiso4217:USDxbrli:sharesxbrli:pureutr:MWhutr:galutr:MMBTUiso4217:USDutr:MWhaee:scrubberaee:siteutr:Yaee:segment00010029102026-01-012026-09-300001002910aee:UnionElectricCompanyMember2026-01-012026-09-300001002910aee:AmerenIllinoisCompanyMember2026-01-012026-09-3000010029102026-10-300001002910aee:UnionElectricCompanyMember2026-10-300001002910aee:AmerenIllinoisCompanyMember2026-10-300001002910us-gaap:ElectricityMember2026-07-012026-09-300001002910us-gaap:ElectricityMember2025-07-012025-09-300001002910us-gaap:ElectricityMember2026-01-012026-09-300001002910us-gaap:ElectricityMember2025-01-012025-09-300001002910srt:NaturalGasReservesMember2026-07-012026-09-300001002910srt:NaturalGasReservesMember2025-07-012025-09-300001002910srt:NaturalGasReservesMember2026-01-012026-09-300001002910srt:NaturalGasReservesMember2025-01-012025-09-3000010029102026-07-012026-09-3000010029102025-07-012025-09-3000010029102025-01-012025-09-3000010029102026-09-3000010029102025-12-310001002910us-gaap:VariableInterestEntityPrimaryBeneficiaryMember2026-09-300001002910us-gaap:VariableInterestEntityPrimaryBeneficiaryMember2025-12-3100010029102024-12-3100010029102025-09-300001002910us-gaap:CommonStockMember2026-09-300001002910us-gaap:CommonStockMember2025-09-300001002910us-gaap:AdditionalPaidInCapitalMember2026-06-300001002910us-gaap:AdditionalPaidInCapitalMember2025-06-300001002910us-gaap:AdditionalPaidInCapitalMember2025-12-310001002910us-gaap:AdditionalPaidInCapitalMember2024-12-310001002910us-gaap:AdditionalPaidInCapitalMember2026-07-012026-09-300001002910us-gaap:AdditionalPaidInCapitalMember2025-07-012025-09-300001002910us-gaap:AdditionalPaidInCapitalMember2026-01-012026-09-300001002910us-gaap:AdditionalPaidInCapitalMember2025-01-012025-09-300001002910us-gaap:AdditionalPaidInCapitalMember2026-09-300001002910us-gaap:AdditionalPaidInCapitalMember2025-09-300001002910us-gaap:RetainedEarningsMember2026-06-300001002910us-gaap:RetainedEarningsMember2025-06-300001002910us-gaap:RetainedEarningsMember2025-12-310001002910us-gaap:RetainedEarningsMember2024-12-310001002910us-gaap:RetainedEarningsMember2026-07-012026-09-300001002910us-gaap:RetainedEarningsMember2025-07-012025-09-300001002910us-gaap:RetainedEarningsMember2026-01-012026-09-300001002910us-gaap:RetainedEarningsMember2025-01-012025-09-300001002910us-gaap:RetainedEarningsMember2026-09-300001002910us-gaap:RetainedEarningsMember2025-09-300001002910aee:DerivativeFinancialInstrumentsMember2026-06-300001002910aee:DerivativeFinancialInstrumentsMember2025-06-300001002910aee:DerivativeFinancialInstrumentsMember2025-12-310001002910aee:DerivativeFinancialInstrumentsMember2024-12-310001002910aee:DerivativeFinancialInstrumentsMember2026-07-012026-09-300001002910aee:DerivativeFinancialInstrumentsMember2025-07-012025-09-300001002910aee:DerivativeFinancialInstrumentsMember2026-01-012026-09-300001002910aee:DerivativeFinancialInstrumentsMember2025-01-012025-09-300001002910aee:DerivativeFinancialInstrumentsMember2026-09-300001002910aee:DerivativeFinancialInstrumentsMember2025-09-300001002910aee:DeferredRetirementBenefitCostsMember2026-06-300001002910aee:DeferredRetirementBenefitCostsMember2025-06-300001002910aee:DeferredRetirementBenefitCostsMember2025-12-310001002910aee:DeferredRetirementBenefitCostsMember2024-12-310001002910aee:DeferredRetirementBenefitCostsMember2026-07-012026-09-300001002910aee:DeferredRetirementBenefitCostsMember2025-07-012025-09-300001002910aee:DeferredRetirementBenefitCostsMember2026-01-012026-09-300001002910aee:DeferredRetirementBenefitCostsMember2025-01-012025-09-300001002910aee:DeferredRetirementBenefitCostsMember2026-09-300001002910aee:DeferredRetirementBenefitCostsMember2025-09-300001002910us-gaap:AccumulatedOtherComprehensiveIncomeMember2026-09-300001002910us-gaap:AccumulatedOtherComprehensiveIncomeMember2025-09-300001002910us-gaap:ParentMember2026-09-300001002910us-gaap:ParentMember2025-09-300001002910us-gaap:NoncontrollingInterestMember2026-06-300001002910us-gaap:NoncontrollingInterestMember2025-06-300001002910us-gaap:NoncontrollingInterestMember2025-12-310001002910us-gaap:NoncontrollingInterestMember2024-12-310001002910us-gaap:NoncontrollingInterestMember2026-07-012026-09-300001002910us-gaap:NoncontrollingInterestMember2025-07-012025-09-300001002910us-gaap:NoncontrollingInterestMember2026-01-012026-09-300001002910us-gaap:NoncontrollingInterestMember2025-01-012025-09-300001002910us-gaap:NoncontrollingInterestMember2026-09-300001002910us-gaap:NoncontrollingInterestMember2025-09-3000010029102026-06-3000010029102025-06-300001002910aee:UnionElectricCompanyMemberus-gaap:ElectricityMember2026-07-012026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:ElectricityMember2025-07-012025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:ElectricityMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:ElectricityMember2025-01-012025-09-300001002910aee:UnionElectricCompanyMembersrt:NaturalGasReservesMember2026-07-012026-09-300001002910aee:UnionElectricCompanyMembersrt:NaturalGasReservesMember2025-07-012025-09-300001002910aee:UnionElectricCompanyMembersrt:NaturalGasReservesMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMembersrt:NaturalGasReservesMember2025-01-012025-09-300001002910aee:UnionElectricCompanyMember2026-07-012026-09-300001002910aee:UnionElectricCompanyMember2025-07-012025-09-300001002910aee:UnionElectricCompanyMember2025-01-012025-09-300001002910aee:UnionElectricCompanyMember2026-09-300001002910aee:UnionElectricCompanyMember2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:NonrelatedPartyMember2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:NonrelatedPartyMember2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-12-310001002910us-gaap:VariableInterestEntityPrimaryBeneficiaryMemberaee:UnionElectricCompanyMember2026-09-300001002910us-gaap:VariableInterestEntityPrimaryBeneficiaryMemberaee:UnionElectricCompanyMember2025-12-310001002910aee:UnionElectricCompanyMember2024-12-310001002910aee:UnionElectricCompanyMember2025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommonStockMember2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommonStockMember2025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:AdditionalPaidInCapitalMember2026-06-300001002910aee:UnionElectricCompanyMemberus-gaap:AdditionalPaidInCapitalMember2025-06-300001002910aee:UnionElectricCompanyMemberus-gaap:AdditionalPaidInCapitalMember2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:AdditionalPaidInCapitalMember2024-12-310001002910aee:UnionElectricCompanyMemberus-gaap:AdditionalPaidInCapitalMember2026-07-012026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:AdditionalPaidInCapitalMember2025-07-012025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:AdditionalPaidInCapitalMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:AdditionalPaidInCapitalMember2025-01-012025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:AdditionalPaidInCapitalMember2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:AdditionalPaidInCapitalMember2025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:PreferredStockMember2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:PreferredStockMember2025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:RetainedEarningsMember2026-06-300001002910aee:UnionElectricCompanyMemberus-gaap:RetainedEarningsMember2025-06-300001002910aee:UnionElectricCompanyMemberus-gaap:RetainedEarningsMember2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:RetainedEarningsMember2024-12-310001002910aee:UnionElectricCompanyMemberus-gaap:RetainedEarningsMember2026-07-012026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:RetainedEarningsMember2025-07-012025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:RetainedEarningsMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:RetainedEarningsMember2025-01-012025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:RetainedEarningsMember2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:RetainedEarningsMember2025-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMember2026-07-012026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMember2025-07-012025-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMember2026-01-012026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMember2025-01-012025-09-300001002910aee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2026-07-012026-09-300001002910aee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2025-07-012025-09-300001002910aee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2026-01-012026-09-300001002910aee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2025-01-012025-09-300001002910aee:AmerenIllinoisCompanyMember2026-07-012026-09-300001002910aee:AmerenIllinoisCompanyMember2025-07-012025-09-300001002910aee:AmerenIllinoisCompanyMember2025-01-012025-09-300001002910aee:AmerenIllinoisCompanyMember2026-09-300001002910aee:AmerenIllinoisCompanyMember2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:NonrelatedPartyMember2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:NonrelatedPartyMember2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-12-310001002910aee:AmerenIllinoisCompanyMember2024-12-310001002910aee:AmerenIllinoisCompanyMember2025-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommonStockMember2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommonStockMember2025-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:AdditionalPaidInCapitalMember2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:AdditionalPaidInCapitalMember2025-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:PreferredStockMember2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:PreferredStockMember2025-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:RetainedEarningsMember2026-06-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:RetainedEarningsMember2025-06-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:RetainedEarningsMember2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:RetainedEarningsMember2024-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:RetainedEarningsMember2026-07-012026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:RetainedEarningsMember2025-07-012025-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:RetainedEarningsMember2026-01-012026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:RetainedEarningsMember2025-01-012025-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:RetainedEarningsMember2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:RetainedEarningsMember2025-09-300001002910us-gaap:VariableInterestEntityPrimaryBeneficiaryMemberaee:AmerenMissouriSecuritizationFundingILLCMember2026-09-300001002910us-gaap:VariableInterestEntityPrimaryBeneficiaryMemberaee:AmerenMissouriSecuritizationFundingILLCMember2025-12-310001002910aee:PartnershipFundingCommitmentMember2026-09-300001002910aee:PendingRateCaseMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMember2026-01-012026-09-300001002910aee:SolarGenerationFacilityMemberaee:UnionElectricCompanyMemberaee:SelfBuildMember2023-10-012023-12-310001002910aee:SolarGenerationFacilityMemberaee:UnionElectricCompanyMemberaee:BuildTransferMember2023-10-012023-12-310001002910aee:NaturalGasGenerationFacilityMemberaee:UnionElectricCompanyMemberaee:SelfBuildMember2024-07-012024-09-300001002910aee:EnergyStorageFacilityMemberaee:UnionElectricCompanyMemberaee:SelfBuildMember2025-04-012025-06-300001002910aee:NaturalGasGenerationFacilityMemberaee:UnionElectricCompanyMemberaee:SelfBuildMember2025-04-012025-06-300001002910aee:SolarGenerationFacilityMemberaee:UnionElectricCompanyMemberaee:SelfBuildMember2025-07-012025-09-300001002910aee:EnergyStorageFacilityMemberaee:UnionElectricCompanyMemberaee:SelfBuildMember2026-05-012026-06-300001002910aee:EnergyStorageFacilityMemberaee:UnionElectricCompanyMemberaee:SelfBuildMember2026-05-012026-05-310001002910aee:EnergyStorageFacilityMemberaee:UnionElectricCompanyMemberaee:SelfBuildMember2026-06-012026-06-300001002910aee:SolarGenerationFacilityMemberaee:UnionElectricCompanyMemberaee:BuildTransferMember2026-05-012026-05-310001002910aee:SolarGenerationFacilityMemberaee:UnionElectricCompanyMemberaee:BuildTransferMember2026-06-012026-06-300001002910aee:NaturalGasGenerationFacilityMemberaee:UnionElectricCompanyMemberaee:SelfBuildMember2026-07-012026-07-310001002910aee:GenerationFacilitiesMembersrt:ScenarioForecastMemberaee:UnionElectricCompanyMember2026-10-012031-12-310001002910aee:SplitRailSolarProjectMemberaee:UnionElectricCompanyMember2026-01-012026-09-300001002910aee:IETLMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricDistributionMember2024-01-012024-12-310001002910aee:IETLMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricDistributionMember2025-01-012025-12-310001002910aee:IETLMembersrt:ScenarioForecastMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricDistributionMember2026-01-012026-12-310001002910aee:IETLMembersrt:ScenarioForecastMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricDistributionMember2027-01-012027-12-310001002910aee:PendingRateCaseMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricDistributionMember2026-01-012026-09-300001002910srt:ScenarioForecastMemberaee:AmerenIllinoisCompanyMember2027-01-012027-12-310001002910srt:ScenarioForecastMemberaee:AmerenIllinoisCompanyMember2028-01-012028-12-310001002910srt:ScenarioForecastMemberaee:AmerenIllinoisCompanyMember2029-01-012029-12-310001002910aee:FinalRateOrderMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2025-11-012025-11-300001002910aee:PendingRateCaseMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2026-01-012026-01-310001002910aee:PendingRateCaseMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2023-10-012023-10-310001002910srt:ScenarioForecastMember2028-01-012028-03-310001002910aee:MidwestIndependentTransmissionSystemOperatorIncMemberaee:FinalRateOrderMember2020-05-012020-05-310001002910aee:MidwestIndependentTransmissionSystemOperatorIncMemberaee:FinalRateOrderMember2024-10-012024-10-310001002910aee:CreditAgreementsMember2026-09-300001002910aee:UnionElectricCompanyMemberaee:MissouriCreditAgreementMember2026-09-300001002910aee:AmerenIllinoisCompanyMemberaee:IllinoisCreditAgreementMember2026-09-300001002910aee:AmerenParentMemberus-gaap:CommercialPaperMember2026-09-300001002910aee:AmerenParentMemberus-gaap:CommercialPaperMember2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommercialPaperMember2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommercialPaperMember2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommercialPaperMember2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommercialPaperMember2025-12-310001002910us-gaap:CommercialPaperMember2026-09-300001002910us-gaap:CommercialPaperMember2025-12-310001002910aee:AmerenParentMember2026-01-012026-09-300001002910aee:AmerenParentMember2026-09-300001002910aee:AmerenParentMember2025-01-012025-09-300001002910aee:AmerenParentMember2025-09-300001002910us-gaap:LetterOfCreditMember2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:LetterOfCreditMemberaee:AmerenLettersOfCreditMember2026-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberus-gaap:LetterOfCreditMemberaee:AmerenLettersOfCreditMember2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:LetterOfCreditMember2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:LetterOfCreditMemberaee:AmerenMissouriLettersOfCreditMember2026-09-300001002910aee:UtilitiesMember2026-07-012026-09-300001002910aee:UtilitiesMember2026-01-012026-09-300001002910aee:UtilitiesMember2025-07-012025-09-300001002910aee:UtilitiesMember2025-01-012025-09-300001002910aee:DividendReinvestmentAnd401KPlansMember2026-07-012026-09-300001002910aee:DividendReinvestmentAnd401KPlansMember2026-01-012026-09-3000010029102026-01-012026-06-3000010029102026-04-012026-06-3000010029102026-05-310001002910srt:MinimumMember2026-01-012026-09-300001002910srt:MaximumMember2026-01-012026-09-300001002910srt:WeightedAverageMember2026-01-012026-09-300001002910aee:ForwardSaleAgreementsOutstandingMember2026-09-300001002910us-gaap:SubsequentEventMember2026-10-310001002910us-gaap:SubsequentEventMembersrt:WeightedAverageMember2026-10-012026-10-310001002910us-gaap:UnsecuredDebtMemberaee:AmerenParentMemberaee:SeniorUnsecuredNotes5.00Due2036Member2026-02-280001002910us-gaap:UnsecuredDebtMemberaee:AmerenParentMemberaee:SeniorUnsecuredNotes3.65Due2026Member2026-02-280001002910us-gaap:UnsecuredDebtMemberaee:AmerenParentMemberaee:JuniorSubordinatedNotes6.45Due2057Member2026-09-3000010029102026-09-012026-09-300001002910us-gaap:UnsecuredDebtMemberaee:AmerenParentMemberaee:JuniorSubordinatedNotes6.45Due2057Member2026-09-012026-09-300001002910us-gaap:UnsecuredDebtMemberaee:AmerenParentMemberaee:JuniorSubordinatedNotes6.45Due2057Membersrt:MinimumMember2026-09-012026-09-300001002910us-gaap:SecuredDebtMemberaee:AmerenParentMemberaee:SeniorSecuredNotesAndFirstMortgageBondsMemberus-gaap:RelatedPartyMember2026-09-300001002910us-gaap:SecuredDebtMemberaee:AmerenParentMemberaee:SeniorSecuredNotesAndFirstMortgageBondsMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910us-gaap:SecuredDebtMemberaee:UnionElectricCompanyMemberaee:FirstMortgageBonds4.80Due2036Member2026-02-280001002910us-gaap:SecuredDebtMemberaee:UnionElectricCompanyMemberaee:FirstMortgageBonds5.55Due2056Member2026-02-280001002910us-gaap:SecuredDebtMemberaee:UnionElectricCompanyMemberaee:FirstMortgageBonds5.75Due2056Member2026-06-300001002910us-gaap:SecuredDebtMemberaee:AmerenIllinoisCompanyMemberaee:FirstMortgageBonds5.50Due2036Member2026-09-300001002910us-gaap:UnsecuredDebtMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:SeniorUnsecuredNotes5.83Due2041Member2026-09-300001002910us-gaap:UnsecuredDebtMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:SeniorUnsecuredNotes6.24Due2054Member2026-09-300001002910us-gaap:InterestRateSwapMember2026-09-300001002910us-gaap:InterestRateSwapMember2025-12-310001002910us-gaap:InterestRateSwapMember2026-07-012026-09-300001002910us-gaap:InterestRateSwapMember2026-01-012026-09-300001002910us-gaap:InterestRateSwapMember2025-07-012025-09-300001002910us-gaap:InterestRateSwapMember2025-01-012025-09-300001002910aee:UnionElectricCompanyMemberaee:FuelOilsMember2026-01-012026-09-300001002910aee:AmerenIllinoisCompanyMemberaee:FuelOilsMember2026-01-012026-09-300001002910aee:FuelOilsMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMemberaee:FuelOilsMember2025-01-012025-12-310001002910aee:AmerenIllinoisCompanyMemberaee:FuelOilsMember2025-01-012025-12-310001002910aee:FuelOilsMember2025-01-012025-12-310001002910aee:UnionElectricCompanyMembersrt:NaturalGasReservesMember2026-01-012026-09-300001002910aee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2026-01-012026-09-300001002910srt:NaturalGasReservesMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMembersrt:NaturalGasReservesMember2025-01-012025-12-310001002910aee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2025-01-012025-12-310001002910srt:NaturalGasReservesMember2025-01-012025-12-310001002910aee:UnionElectricCompanyMemberaee:PowerMember2026-01-012026-09-300001002910aee:AmerenIllinoisCompanyMemberaee:PowerMember2026-01-012026-09-300001002910aee:PowerMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMemberaee:PowerMember2025-01-012025-12-310001002910aee:AmerenIllinoisCompanyMemberaee:PowerMember2025-01-012025-12-310001002910aee:PowerMember2025-01-012025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:UnionElectricCompanyMemberaee:FuelOilsMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:AmerenIllinoisCompanyMemberaee:FuelOilsMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:FuelOilsMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:UnionElectricCompanyMemberaee:FuelOilsMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:AmerenIllinoisCompanyMemberaee:FuelOilsMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:FuelOilsMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:UnionElectricCompanyMemberaee:FuelOilsMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:AmerenIllinoisCompanyMemberaee:FuelOilsMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:FuelOilsMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:UnionElectricCompanyMemberaee:FuelOilsMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:AmerenIllinoisCompanyMemberaee:FuelOilsMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:FuelOilsMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:UnionElectricCompanyMembersrt:NaturalGasReservesMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentsrt:NaturalGasReservesMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:UnionElectricCompanyMembersrt:NaturalGasReservesMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentsrt:NaturalGasReservesMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:UnionElectricCompanyMembersrt:NaturalGasReservesMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentsrt:NaturalGasReservesMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:UnionElectricCompanyMembersrt:NaturalGasReservesMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentsrt:NaturalGasReservesMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:UnionElectricCompanyMemberaee:PowerMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:AmerenIllinoisCompanyMemberaee:PowerMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:PowerMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:UnionElectricCompanyMemberaee:PowerMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:AmerenIllinoisCompanyMemberaee:PowerMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsCurrentaee:PowerMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:UnionElectricCompanyMemberaee:PowerMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:AmerenIllinoisCompanyMemberaee:PowerMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:PowerMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:UnionElectricCompanyMemberaee:PowerMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:AmerenIllinoisCompanyMemberaee:PowerMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherAssetsNoncurrentaee:PowerMember2025-12-310001002910us-gaap:NondesignatedMemberaee:UnionElectricCompanyMember2026-09-300001002910us-gaap:NondesignatedMemberaee:AmerenIllinoisCompanyMember2026-09-300001002910us-gaap:NondesignatedMember2026-09-300001002910us-gaap:NondesignatedMemberaee:UnionElectricCompanyMember2025-12-310001002910us-gaap:NondesignatedMemberaee:AmerenIllinoisCompanyMember2025-12-310001002910us-gaap:NondesignatedMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:UnionElectricCompanyMemberaee:FuelOilsMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:AmerenIllinoisCompanyMemberaee:FuelOilsMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:FuelOilsMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:UnionElectricCompanyMemberaee:FuelOilsMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:AmerenIllinoisCompanyMemberaee:FuelOilsMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:FuelOilsMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:UnionElectricCompanyMemberaee:FuelOilsMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:AmerenIllinoisCompanyMemberaee:FuelOilsMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:FuelOilsMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:UnionElectricCompanyMemberaee:FuelOilsMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:AmerenIllinoisCompanyMemberaee:FuelOilsMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:FuelOilsMember2025-12-310001002910us-gaap:NondesignatedMemberaee:MarkToMarketDerivativeLiabilitiesaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2026-09-300001002910us-gaap:NondesignatedMemberaee:MarkToMarketDerivativeLiabilitiesaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:UnionElectricCompanyMembersrt:NaturalGasReservesMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentsrt:NaturalGasReservesMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:UnionElectricCompanyMembersrt:NaturalGasReservesMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentsrt:NaturalGasReservesMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:UnionElectricCompanyMembersrt:NaturalGasReservesMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentsrt:NaturalGasReservesMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:UnionElectricCompanyMembersrt:NaturalGasReservesMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentsrt:NaturalGasReservesMember2025-12-310001002910us-gaap:NondesignatedMemberaee:MarkToMarketDerivativeLiabilitiesaee:AmerenIllinoisCompanyMemberaee:PowerMember2026-09-300001002910us-gaap:NondesignatedMemberaee:MarkToMarketDerivativeLiabilitiesaee:AmerenIllinoisCompanyMemberaee:PowerMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:UnionElectricCompanyMemberaee:PowerMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:AmerenIllinoisCompanyMemberaee:PowerMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:PowerMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:UnionElectricCompanyMemberaee:PowerMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:AmerenIllinoisCompanyMemberaee:PowerMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesCurrentaee:PowerMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:UnionElectricCompanyMemberaee:PowerMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:AmerenIllinoisCompanyMemberaee:PowerMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:PowerMember2026-09-300001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:UnionElectricCompanyMemberaee:PowerMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:AmerenIllinoisCompanyMemberaee:PowerMember2025-12-310001002910us-gaap:NondesignatedMemberus-gaap:OtherLiabilitiesNoncurrentaee:PowerMember2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:FuelOilsMemberus-gaap:FairValueInputsLevel1Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:FuelOilsMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:FuelOilsMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:FuelOilsMember2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:FuelOilsMemberus-gaap:FairValueInputsLevel1Member2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:FuelOilsMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:FuelOilsMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:FuelOilsMember2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMemberus-gaap:FairValueInputsLevel1Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMember2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMemberus-gaap:FairValueInputsLevel1Member2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMember2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:PowerMemberus-gaap:FairValueInputsLevel1Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:PowerMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:PowerMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:PowerMember2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:PowerMemberus-gaap:FairValueInputsLevel1Member2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:PowerMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:PowerMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberaee:PowerMember2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel1Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMember2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel1Member2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:CommodityContractMember2025-12-310001002910aee:USLargeCapitalizationMemberus-gaap:EquitySecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel1Member2026-09-300001002910aee:USLargeCapitalizationMemberus-gaap:EquitySecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910aee:USLargeCapitalizationMemberus-gaap:EquitySecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910aee:USLargeCapitalizationMemberus-gaap:EquitySecuritiesMemberaee:UnionElectricCompanyMember2026-09-300001002910aee:USLargeCapitalizationMemberus-gaap:EquitySecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel1Member2025-12-310001002910aee:USLargeCapitalizationMemberus-gaap:EquitySecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910aee:USLargeCapitalizationMemberus-gaap:EquitySecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910aee:USLargeCapitalizationMemberus-gaap:EquitySecuritiesMemberaee:UnionElectricCompanyMember2025-12-310001002910us-gaap:USTreasuryAndGovernmentMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel1Member2026-09-300001002910us-gaap:USTreasuryAndGovernmentMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910us-gaap:USTreasuryAndGovernmentMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910us-gaap:USTreasuryAndGovernmentMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMember2026-09-300001002910us-gaap:USTreasuryAndGovernmentMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel1Member2025-12-310001002910us-gaap:USTreasuryAndGovernmentMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910us-gaap:USTreasuryAndGovernmentMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910us-gaap:USTreasuryAndGovernmentMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMember2025-12-310001002910us-gaap:CorporateDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel1Member2026-09-300001002910us-gaap:CorporateDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910us-gaap:CorporateDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910us-gaap:CorporateDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMember2026-09-300001002910us-gaap:CorporateDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel1Member2025-12-310001002910us-gaap:CorporateDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910us-gaap:CorporateDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910us-gaap:CorporateDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMember2025-12-310001002910us-gaap:OtherDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel1Member2026-09-300001002910us-gaap:OtherDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910us-gaap:OtherDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910us-gaap:OtherDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMember2026-09-300001002910us-gaap:OtherDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel1Member2025-12-310001002910us-gaap:OtherDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910us-gaap:OtherDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910us-gaap:OtherDebtSecuritiesMemberus-gaap:DebtSecuritiesMemberaee:UnionElectricCompanyMember2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel1Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel1Member2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910aee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMemberus-gaap:FairValueInputsLevel1Member2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMember2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMemberus-gaap:FairValueInputsLevel1Member2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMembersrt:NaturalGasReservesMember2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMemberaee:PowerMemberus-gaap:FairValueInputsLevel1Member2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMemberaee:PowerMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMemberaee:PowerMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMemberaee:PowerMember2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMemberaee:PowerMemberus-gaap:FairValueInputsLevel1Member2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMemberaee:PowerMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMemberaee:PowerMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMemberaee:PowerMember2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:FairValueInputsLevel1Member2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:FairValueInputsLevel1Member2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910us-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel1Member2026-09-300001002910us-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910us-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910us-gaap:CommodityContractMember2026-09-300001002910us-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel1Member2025-12-310001002910us-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910us-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910us-gaap:CommodityContractMember2025-12-310001002910us-gaap:FairValueInputsLevel1Member2026-09-300001002910us-gaap:FairValueInputsLevel2Member2026-09-300001002910us-gaap:FairValueInputsLevel3Member2026-09-300001002910us-gaap:FairValueInputsLevel1Member2025-12-310001002910us-gaap:FairValueInputsLevel2Member2025-12-310001002910us-gaap:FairValueInputsLevel3Member2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel1Member2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMember2026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel1Member2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910aee:AmerenIllinoisCompanyMemberus-gaap:CommodityContractMember2025-12-310001002910aee:UnionElectricCompanyMemberaee:PowerMember2026-06-300001002910aee:AmerenIllinoisCompanyMemberaee:PowerMember2026-06-300001002910aee:PowerMember2026-06-300001002910aee:UnionElectricCompanyMemberaee:PowerMember2026-07-012026-09-300001002910aee:AmerenIllinoisCompanyMemberaee:PowerMember2026-07-012026-09-300001002910aee:PowerMember2026-07-012026-09-300001002910aee:UnionElectricCompanyMemberaee:PowerMember2026-09-300001002910aee:AmerenIllinoisCompanyMemberaee:PowerMember2026-09-300001002910aee:PowerMember2026-09-300001002910aee:UnionElectricCompanyMemberaee:PowerMember2025-12-310001002910aee:AmerenIllinoisCompanyMemberaee:PowerMember2025-12-310001002910aee:PowerMember2025-12-310001002910aee:UnionElectricCompanyMemberaee:PowerMember2026-01-012026-09-300001002910aee:AmerenIllinoisCompanyMemberaee:PowerMember2026-01-012026-09-300001002910aee:PowerMember2026-01-012026-09-300001002910aee:PowerMemberus-gaap:MeasurementInputCommodityForwardPriceMembersrt:MinimumMemberaee:DiscountedCashFlowMember2026-09-300001002910aee:PowerMemberus-gaap:MeasurementInputCommodityForwardPriceMembersrt:MaximumMemberaee:DiscountedCashFlowMember2026-09-300001002910aee:PowerMemberus-gaap:MeasurementInputCommodityForwardPriceMembersrt:WeightedAverageMemberaee:DiscountedCashFlowMember2026-09-300001002910aee:PowerMemberaee:MeasurementInputNodalBasisMembersrt:MinimumMemberaee:DiscountedCashFlowMember2026-09-300001002910aee:PowerMemberaee:MeasurementInputNodalBasisMembersrt:MaximumMemberaee:DiscountedCashFlowMember2026-09-300001002910aee:PowerMemberaee:MeasurementInputNodalBasisMembersrt:WeightedAverageMemberaee:DiscountedCashFlowMember2026-09-300001002910aee:PowerMemberus-gaap:MeasurementInputCommodityForwardPriceMembersrt:MinimumMemberaee:DiscountedCashFlowMember2025-12-310001002910aee:PowerMemberus-gaap:MeasurementInputCommodityForwardPriceMembersrt:MaximumMemberaee:DiscountedCashFlowMember2025-12-310001002910aee:PowerMemberus-gaap:MeasurementInputCommodityForwardPriceMembersrt:WeightedAverageMemberaee:DiscountedCashFlowMember2025-12-310001002910aee:PowerMemberaee:MeasurementInputNodalBasisMembersrt:MinimumMemberaee:DiscountedCashFlowMember2025-12-310001002910aee:PowerMemberaee:MeasurementInputNodalBasisMembersrt:MaximumMemberaee:DiscountedCashFlowMember2025-12-310001002910aee:PowerMemberaee:MeasurementInputNodalBasisMembersrt:WeightedAverageMemberaee:DiscountedCashFlowMember2025-12-310001002910us-gaap:CarryingReportedAmountFairValueDisclosureMember2026-09-300001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910us-gaap:EstimateOfFairValueFairValueDisclosureMember2026-09-300001002910us-gaap:CarryingReportedAmountFairValueDisclosureMemberaee:UnionElectricCompanyMember2026-09-300001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberaee:UnionElectricCompanyMember2026-09-300001002910us-gaap:CarryingReportedAmountFairValueDisclosureMemberaee:AmerenIllinoisCompanyMember2026-09-300001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberaee:AmerenIllinoisCompanyMemberus-gaap:FairValueInputsLevel2Member2026-09-300001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberaee:AmerenIllinoisCompanyMemberus-gaap:FairValueInputsLevel3Member2026-09-300001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberaee:AmerenIllinoisCompanyMember2026-09-300001002910us-gaap:CarryingReportedAmountFairValueDisclosureMember2025-12-310001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910us-gaap:EstimateOfFairValueFairValueDisclosureMember2025-12-310001002910us-gaap:CarryingReportedAmountFairValueDisclosureMemberaee:UnionElectricCompanyMember2025-12-310001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberaee:UnionElectricCompanyMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberaee:UnionElectricCompanyMember2025-12-310001002910us-gaap:CarryingReportedAmountFairValueDisclosureMemberaee:AmerenIllinoisCompanyMember2025-12-310001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberaee:AmerenIllinoisCompanyMemberus-gaap:FairValueInputsLevel2Member2025-12-310001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberaee:AmerenIllinoisCompanyMemberus-gaap:FairValueInputsLevel3Member2025-12-310001002910us-gaap:EstimateOfFairValueFairValueDisclosureMemberaee:AmerenIllinoisCompanyMember2025-12-310001002910aee:AmerenServicesSupportServicesAgreementMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-09-300001002910aee:AmerenServicesSupportServicesAgreementMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-09-300001002910aee:AmerenServicesSupportServicesAgreementMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-12-310001002910aee:AmerenServicesSupportServicesAgreementMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-12-310001002910aee:IncometaxespayabletoparentMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-09-300001002910aee:IncometaxespayabletoparentMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-09-300001002910aee:IncometaxespayabletoparentMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-12-310001002910aee:IncometaxespayabletoparentMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-12-310001002910aee:IncometaxesreceivablefromparentMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-09-300001002910aee:IncometaxesreceivablefromparentMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-09-300001002910aee:IncometaxesreceivablefromparentMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-12-310001002910aee:IncometaxesreceivablefromparentMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-12-310001002910aee:AmerenMissouriAndAmerenIllinoisRentAndFacilityServicesMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:AmerenMissouriAndAmerenIllinoisRentAndFacilityServicesMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:AmerenMissouriAndAmerenIllinoisRentAndFacilityServicesMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:AmerenMissouriAndAmerenIllinoisRentAndFacilityServicesMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:AmerenMissouriAndAmerenIllinoisRentAndFacilityServicesMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:AmerenIllinoisInterconnectionAgreementWithAmerenMissouriMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:AmerenIllinoisInterconnectionAgreementWithAmerenMissouriMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:AmerenMissouriandAmerenIllinoismiscellaneoussupportservicesMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:AmerenMissouriandAmerenIllinoismiscellaneoussupportservicesMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:AmerenMissouriandAmerenIllinoismiscellaneoussupportservicesMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:AmerenMissouriandAmerenIllinoismiscellaneoussupportservicesMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:AmerenMissouriandAmerenIllinoismiscellaneoussupportservicesMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:AmerenMissouriandAmerenIllinoismiscellaneoussupportservicesMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:TotalRelatedPartyOperatingRevenuesMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:TotalRelatedPartyOperatingRevenuesMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:TotalRelatedPartyOperatingRevenuesMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:TotalRelatedPartyOperatingRevenuesMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:TotalRelatedPartyOperatingRevenuesMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:TotalRelatedPartyOperatingRevenuesMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:TotalRelatedPartyOperatingRevenuesMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:AmerenMissouriAndAmerenIllinoisTransmissionServicesFromATXIMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:AmerenMissouriAndAmerenIllinoisTransmissionServicesFromATXIMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:AmerenMissouriAndAmerenIllinoisTransmissionServicesFromATXIMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:AmerenMissouriAndAmerenIllinoisTransmissionServicesFromATXIMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:AmerenMissouriAndAmerenIllinoisTransmissionServicesFromATXIMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:AmerenMissouriAndAmerenIllinoisTransmissionServicesFromATXIMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:AmerenMissouriAndAmerenIllinoisTransmissionServicesFromATXIMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:AmerenMissouriInterconnectionAgreementWithAmerenIllinoisMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:AmerenMissouriInterconnectionAgreementWithAmerenIllinoisMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:PurchasedPowerMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:PurchasedPowerMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:PurchasedPowerMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:PurchasedPowerMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:PurchasedPowerMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:PurchasedPowerMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:PurchasedPowerMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:AmerenMissouriAndAmerenIllinoisRentAndFacilityServicesMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:AmerenMissouriAndAmerenIllinoisRentAndFacilityServicesMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:AmerenServicesSupportServicesAgreementMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:AmerenServicesSupportServicesAgreementMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:AmerenServicesSupportServicesAgreementMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:AmerenServicesSupportServicesAgreementMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:AmerenServicesSupportServicesAgreementMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:AmerenServicesSupportServicesAgreementMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:AmerenServicesSupportServicesAgreementMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:AmerenServicesSupportServicesAgreementMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:TotalRelatedPartyOtherOperationsandMaintenanceMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:TotalRelatedPartyOtherOperationsandMaintenanceMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:TotalRelatedPartyOtherOperationsandMaintenanceMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:TotalRelatedPartyOtherOperationsandMaintenanceMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:TotalRelatedPartyOtherOperationsandMaintenanceMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:TotalRelatedPartyOtherOperationsandMaintenanceMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:TotalRelatedPartyOtherOperationsandMaintenanceMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:TotalRelatedPartyOtherOperationsandMaintenanceMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910us-gaap:LongTermDebtMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910us-gaap:LongTermDebtMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910us-gaap:LongTermDebtMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910us-gaap:LongTermDebtMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:MoneyPoolMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:MoneyPoolMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:MoneyPoolMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910us-gaap:LongTermDebtMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910us-gaap:LongTermDebtMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-01-012026-09-300001002910aee:MoneyPoolMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:AmerenIllinoisInterconnectionAgreementWithAmerenMissouriMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:AmerenMissouriInterconnectionAgreementWithAmerenIllinoisMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-01-012025-09-300001002910aee:AmerenIllinoisInterconnectionAgreementWithAmerenMissouriMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:AmerenMissouriInterconnectionAgreementWithAmerenIllinoisMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:MoneyPoolMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:MoneyPoolMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910us-gaap:LongTermDebtMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910us-gaap:LongTermDebtMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:MoneyPoolMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:MoneyPoolMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:AmerenMissouriAndAmerenIllinoisRentAndFacilityServicesMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:AmerenMissouriandAmerenIllinoismiscellaneoussupportservicesMemberaee:UnionElectricCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:AmerenMissouriandAmerenIllinoismiscellaneoussupportservicesMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:TotalRelatedPartyOperatingRevenuesMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2025-07-012025-09-300001002910aee:AmerenMissouriAndAmerenIllinoisTransmissionServicesFromATXIMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910aee:PurchasedPowerMemberaee:AmerenIllinoisCompanyMemberus-gaap:RelatedPartyMember2026-07-012026-09-300001002910srt:MinimumMember2026-09-300001002910aee:UnionElectricCompanyMembersrt:MinimumMember2026-09-300001002910srt:MaximumMember2026-09-300001002910aee:UnionElectricCompanyMembersrt:MaximumMember2026-09-300001002910aee:NewCCRRulesEstimateMember2026-09-300001002910aee:UnionElectricCompanyMemberaee:NewCCRRulesEstimateMember2026-09-300001002910aee:AmerenIllinoisCompanyMemberaee:ManufacturedGasPlantMember2026-09-300001002910aee:AmerenIllinoisCompanyMembersrt:MinimumMemberaee:ManufacturedGasPlantMember2026-09-300001002910aee:AmerenIllinoisCompanyMembersrt:MaximumMemberaee:ManufacturedGasPlantMember2026-09-300001002910aee:ManufacturedGasPlantMember2026-09-300001002910aee:UnionElectricCompanyMemberaee:PublicLiabilityAndNuclearWorkerLiabilityAmericanNuclearInsurersMember2026-09-300001002910aee:UnionElectricCompanyMemberaee:PublicLiabilityAndNuclearWorkerLiabilityPoolParticipationMember2026-09-300001002910aee:UnionElectricCompanyMemberaee:PublicLiabilityMember2026-09-300001002910aee:UnionElectricCompanyMemberaee:PropertyDamageNuclearElectricInsuranceLtdMember2026-09-300001002910aee:UnionElectricCompanyMemberaee:AccidentalOutageNuclearElectricInsuranceLtdMember2026-09-300001002910aee:UnionElectricCompanyMemberaee:PublicLiabilityAndNuclearWorkerLiabilityPoolParticipationMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMemberaee:RadiationEventMember2026-09-300001002910aee:NonradiationeventMember2026-09-300001002910aee:UnionElectricCompanyMemberaee:PropertyDamageEuropeanMutualAssociationforNuclearInsuranceMember2026-09-300001002910aee:UnionElectricCompanyMemberaee:AccidentalOutageNuclearElectricInsuranceLtdMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMemberaee:RadiationEventMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMemberaee:NonradiationeventMember2026-01-012026-09-300001002910us-gaap:PensionPlansDefinedBenefitMember2026-07-012026-09-300001002910us-gaap:PensionPlansDefinedBenefitMember2025-07-012025-09-300001002910us-gaap:PensionPlansDefinedBenefitMember2026-01-012026-09-300001002910us-gaap:PensionPlansDefinedBenefitMember2025-01-012025-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2026-07-012026-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2025-07-012025-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2026-01-012026-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2025-01-012025-09-300001002910us-gaap:PensionPlansDefinedBenefitMemberaee:UnionElectricCompanyMember2026-07-012026-09-300001002910us-gaap:PensionPlansDefinedBenefitMemberaee:UnionElectricCompanyMember2025-07-012025-09-300001002910us-gaap:PensionPlansDefinedBenefitMemberaee:UnionElectricCompanyMember2026-01-012026-09-300001002910us-gaap:PensionPlansDefinedBenefitMemberaee:UnionElectricCompanyMember2025-01-012025-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberaee:UnionElectricCompanyMember2026-07-012026-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberaee:UnionElectricCompanyMember2025-07-012025-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberaee:UnionElectricCompanyMember2026-01-012026-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberaee:UnionElectricCompanyMember2025-01-012025-09-300001002910us-gaap:PensionPlansDefinedBenefitMemberaee:AmerenIllinoisCompanyMember2026-07-012026-09-300001002910us-gaap:PensionPlansDefinedBenefitMemberaee:AmerenIllinoisCompanyMember2025-07-012025-09-300001002910us-gaap:PensionPlansDefinedBenefitMemberaee:AmerenIllinoisCompanyMember2026-01-012026-09-300001002910us-gaap:PensionPlansDefinedBenefitMemberaee:AmerenIllinoisCompanyMember2025-01-012025-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberaee:AmerenIllinoisCompanyMember2026-07-012026-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberaee:AmerenIllinoisCompanyMember2025-07-012025-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberaee:AmerenIllinoisCompanyMember2026-01-012026-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberaee:AmerenIllinoisCompanyMember2025-01-012025-09-300001002910us-gaap:PensionPlansDefinedBenefitMemberaee:OtherAffiliatedEntitiesAndIntercompanyEliminationsMember2026-07-012026-09-300001002910us-gaap:PensionPlansDefinedBenefitMemberaee:OtherAffiliatedEntitiesAndIntercompanyEliminationsMember2025-07-012025-09-300001002910us-gaap:PensionPlansDefinedBenefitMemberaee:OtherAffiliatedEntitiesAndIntercompanyEliminationsMember2026-01-012026-09-300001002910us-gaap:PensionPlansDefinedBenefitMemberaee:OtherAffiliatedEntitiesAndIntercompanyEliminationsMember2025-01-012025-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberaee:OtherAffiliatedEntitiesAndIntercompanyEliminationsMember2025-07-012025-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberaee:OtherAffiliatedEntitiesAndIntercompanyEliminationsMember2025-01-012025-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberaee:OtherAffiliatedEntitiesAndIntercompanyEliminationsMember2026-07-012026-09-300001002910us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberaee:OtherAffiliatedEntitiesAndIntercompanyEliminationsMember2026-01-012026-09-300001002910aee:AmerenParentMember2025-07-012025-09-300001002910aee:PrivateLetterRulingMember2025-01-012025-09-300001002910aee:PrivateLetterRulingMemberaee:AmerenIllinoisCompanyMember2025-01-012025-09-300001002910aee:UnionElectricCompanyMember2026-06-300001002910aee:UnionElectricCompanyMember2025-06-300001002910aee:AmerenIllinoisCompanyMember2026-06-300001002910aee:AmerenIllinoisCompanyMember2025-06-300001002910aee:IssuanceOfCommonStockForStockBasedCompensationMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMemberaee:IssuanceOfCommonStockForStockBasedCompensationMember2026-01-012026-09-300001002910aee:AmerenIllinoisCompanyMemberaee:IssuanceOfCommonStockForStockBasedCompensationMember2026-01-012026-09-300001002910aee:IssuanceOfCommonStockForStockBasedCompensationMember2025-01-012025-09-300001002910aee:UnionElectricCompanyMemberaee:IssuanceOfCommonStockForStockBasedCompensationMember2025-01-012025-09-300001002910aee:AmerenIllinoisCompanyMemberaee:IssuanceOfCommonStockForStockBasedCompensationMember2025-01-012025-09-300001002910aee:IssuanceOfCommonStockUnderTheDRPlusMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMemberaee:IssuanceOfCommonStockUnderTheDRPlusMember2026-01-012026-09-300001002910aee:AmerenIllinoisCompanyMemberaee:IssuanceOfCommonStockUnderTheDRPlusMember2026-01-012026-09-300001002910aee:IssuanceOfCommonStockUnderTheDRPlusMember2025-01-012025-09-300001002910aee:UnionElectricCompanyMemberaee:IssuanceOfCommonStockUnderTheDRPlusMember2025-01-012025-09-300001002910aee:AmerenIllinoisCompanyMemberaee:IssuanceOfCommonStockUnderTheDRPlusMember2025-01-012025-09-300001002910us-gaap:OtherLiabilitiesCurrent2026-09-300001002910us-gaap:OtherLiabilitiesCurrent2025-12-310001002910us-gaap:PerformanceSharesMember2026-01-012026-09-300001002910us-gaap:PerformanceSharesMember2025-01-012025-09-300001002910us-gaap:PerformanceSharesMember2025-07-012025-09-300001002910us-gaap:PerformanceSharesMember2026-07-012026-09-300001002910us-gaap:ForwardContractsMember2026-07-012026-09-300001002910us-gaap:ForwardContractsMember2026-01-012026-09-300001002910us-gaap:ForwardContractsMember2025-07-012025-09-300001002910us-gaap:ForwardContractsMember2025-01-012025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:AmerenIllinoisGasSegmentMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:AmerenTransmissionSegmentMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:AmerenIllinoisGasSegmentMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:AmerenTransmissionSegmentMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910us-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910us-gaap:MaterialReconcilingItemsMember2026-07-012026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:AmerenIllinoisGasSegmentMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:AmerenTransmissionSegmentMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:AmerenIllinoisGasSegmentMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:AmerenTransmissionSegmentMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910us-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910us-gaap:MaterialReconcilingItemsMember2025-07-012025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:AmerenIllinoisGasSegmentMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:AmerenTransmissionSegmentMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:AmerenIllinoisGasSegmentMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:AmerenTransmissionSegmentMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910us-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910us-gaap:MaterialReconcilingItemsMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenIllinoisGasSegmentMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenTransmissionSegmentMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:AmerenIllinoisGasSegmentMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:AmerenTransmissionSegmentMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910us-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910us-gaap:MaterialReconcilingItemsMember2025-01-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:ResidentialMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:ResidentialMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:ResidentialMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:ResidentialMemberus-gaap:ElectricityMember2026-07-012026-09-300001002910aee:CommercialMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:CommercialMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:CommercialMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:CommercialMemberus-gaap:ElectricityMember2026-07-012026-09-300001002910aee:IndustrialMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:IndustrialMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:IndustrialMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:IndustrialMemberus-gaap:ElectricityMember2026-07-012026-09-300001002910aee:OtherMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:OtherMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:OtherMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:OtherMemberus-gaap:ElectricityMember2026-07-012026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910us-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:ResidentialMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:ResidentialMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:ResidentialMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:ResidentialMembersrt:NaturalGasReservesMember2026-07-012026-09-300001002910aee:CommercialMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:CommercialMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:CommercialMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:CommercialMembersrt:NaturalGasReservesMember2026-07-012026-09-300001002910aee:IndustrialMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:IndustrialMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:IndustrialMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:IndustrialMembersrt:NaturalGasReservesMember2026-07-012026-09-300001002910aee:OtherMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:OtherMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:OtherMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:OtherMembersrt:NaturalGasReservesMember2026-07-012026-09-300001002910aee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910srt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:ResidentialMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:ResidentialMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:ResidentialMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:ResidentialMemberus-gaap:ElectricityMember2025-07-012025-09-300001002910aee:CommercialMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:CommercialMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:CommercialMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:CommercialMemberus-gaap:ElectricityMember2025-07-012025-09-300001002910aee:IndustrialMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:IndustrialMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:IndustrialMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:IndustrialMemberus-gaap:ElectricityMember2025-07-012025-09-300001002910aee:OtherMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:OtherMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:OtherMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:OtherMemberus-gaap:ElectricityMember2025-07-012025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910us-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:ResidentialMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:ResidentialMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:ResidentialMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:ResidentialMembersrt:NaturalGasReservesMember2025-07-012025-09-300001002910aee:CommercialMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:CommercialMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:CommercialMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:CommercialMembersrt:NaturalGasReservesMember2025-07-012025-09-300001002910aee:IndustrialMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:IndustrialMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:IndustrialMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:IndustrialMembersrt:NaturalGasReservesMember2025-07-012025-09-300001002910aee:OtherMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:OtherMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:OtherMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:OtherMembersrt:NaturalGasReservesMember2025-07-012025-09-300001002910aee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910srt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:ResidentialMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:ResidentialMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:ResidentialMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:ResidentialMemberus-gaap:ElectricityMember2026-01-012026-09-300001002910aee:CommercialMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:CommercialMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:CommercialMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:CommercialMemberus-gaap:ElectricityMember2026-01-012026-09-300001002910aee:IndustrialMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:IndustrialMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:IndustrialMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:IndustrialMemberus-gaap:ElectricityMember2026-01-012026-09-300001002910aee:OtherMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:OtherMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:OtherMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:OtherMemberus-gaap:ElectricityMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910us-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:ResidentialMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:ResidentialMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:ResidentialMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:ResidentialMembersrt:NaturalGasReservesMember2026-01-012026-09-300001002910aee:CommercialMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:CommercialMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:CommercialMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:CommercialMembersrt:NaturalGasReservesMember2026-01-012026-09-300001002910aee:IndustrialMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:IndustrialMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:IndustrialMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:IndustrialMembersrt:NaturalGasReservesMember2026-01-012026-09-300001002910aee:OtherMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:OtherMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:OtherMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:OtherMembersrt:NaturalGasReservesMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910srt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:ResidentialMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:ResidentialMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:ResidentialMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:ResidentialMemberus-gaap:ElectricityMember2025-01-012025-09-300001002910aee:CommercialMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:CommercialMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:CommercialMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:CommercialMemberus-gaap:ElectricityMember2025-01-012025-09-300001002910aee:IndustrialMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:IndustrialMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:IndustrialMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:IndustrialMemberus-gaap:ElectricityMember2025-01-012025-09-300001002910aee:OtherMemberaee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:OtherMemberaee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:OtherMemberus-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:OtherMemberus-gaap:ElectricityMember2025-01-012025-09-300001002910aee:UnionElectricCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenIllinoisGasSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenTransmissionSegmentMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910us-gaap:ElectricityMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:ResidentialMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:ResidentialMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:ResidentialMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:ResidentialMembersrt:NaturalGasReservesMember2025-01-012025-09-300001002910aee:CommercialMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:CommercialMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:CommercialMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:CommercialMembersrt:NaturalGasReservesMember2025-01-012025-09-300001002910aee:IndustrialMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:IndustrialMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:IndustrialMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:IndustrialMembersrt:NaturalGasReservesMember2025-01-012025-09-300001002910aee:OtherMemberaee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:OtherMemberaee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:OtherMembersrt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:OtherMembersrt:NaturalGasReservesMember2025-01-012025-09-300001002910aee:UnionElectricCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenIllinoisGasSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenTransmissionSegmentMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910srt:NaturalGasReservesMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:UnionElectricCompanyMember2026-07-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMember2026-07-012026-09-300001002910aee:AmerenIllinoisGasSegmentMember2026-07-012026-09-300001002910aee:AmerenTransmissionSegmentMember2026-07-012026-09-300001002910aee:UnionElectricCompanyMember2025-07-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMember2025-07-012025-09-300001002910aee:AmerenIllinoisGasSegmentMember2025-07-012025-09-300001002910aee:AmerenTransmissionSegmentMember2025-07-012025-09-300001002910aee:UnionElectricCompanyMember2026-01-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMember2026-01-012026-09-300001002910aee:AmerenIllinoisGasSegmentMember2026-01-012026-09-300001002910aee:AmerenTransmissionSegmentMember2026-01-012026-09-300001002910aee:UnionElectricCompanyMember2025-01-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMember2025-01-012025-09-300001002910aee:AmerenIllinoisGasSegmentMember2025-01-012025-09-300001002910aee:AmerenTransmissionSegmentMember2025-01-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisCompanyMember2026-07-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisCompanyMember2026-07-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisCompanyMember2026-07-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-07-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisCompanyMember2026-07-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-07-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisCompanyMember2025-07-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisCompanyMember2025-07-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisCompanyMember2025-07-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-07-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisCompanyMember2025-07-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-07-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisCompanyMember2026-01-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:CommercialMemberaee:AmerenIllinoisCompanyMember2026-01-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisCompanyMember2026-01-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2026-01-012026-09-300001002910aee:OtherMemberaee:AmerenIllinoisCompanyMember2026-01-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2026-01-012026-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:ResidentialMemberaee:AmerenIllinoisCompanyMember2025-01-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:CommercialMemberaee:AmerenIllinoisCompanyMember2025-01-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:IndustrialMemberaee:AmerenIllinoisCompanyMember2025-01-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisCompanyMemberus-gaap:IntersegmentEliminationMember2025-01-012025-09-300001002910aee:OtherMemberaee:AmerenIllinoisCompanyMember2025-01-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMembersrt:NaturalGasReservesMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMemberus-gaap:ElectricityMemberus-gaap:OperatingSegmentsMember2025-01-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMember2026-07-012026-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMember2026-07-012026-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMember2026-07-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMember2025-07-012025-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMember2025-07-012025-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMember2025-07-012025-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMember2026-01-012026-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMember2026-01-012026-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMember2026-01-012026-09-300001002910aee:AmerenIllinoisElectricDistributionSegmentMemberaee:AmerenIllinoisCompanyMember2025-01-012025-09-300001002910aee:AmerenIllinoisGasSegmentMemberaee:AmerenIllinoisCompanyMember2025-01-012025-09-300001002910aee:AmerenIllinoisTransmissionSegmentMemberaee:AmerenIllinoisCompanyMember2025-01-012025-09-300001002910aee:TheresaA.ShawMember2026-07-012026-09-300001002910aee:TheresaA.ShawMember2026-09-30

Table of Contents

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

 

☒			Quarterly report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for the Quarterly Period Ended September 30, 2026

OR

☐			Transition report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for the transition period from             to

Commission File Number			Exact name of registrant as specified in its charter; State of Incorporation; Address and Telephone Number			IRS Employer Identification No.
1-14756			Ameren Corporation			43-1723446

(Missouri Corporation)

1901 Chouteau Avenue

St. Louis, Missouri 63103

(314) 621-3222

1-2967			Union Electric Company			43-0559760

(Missouri Corporation)

1901 Chouteau Avenue

St. Louis, Missouri 63103

(314) 621-3222

1-3672			Ameren Illinois Company			37-0211380

(Illinois Corporation)

10 Richard Mark Way

Collinsville, Illinois 62234

(618) 343-8150

Securities Registered Pursuant to Section 12(b) of the Act:

Title of each class			Trading Symbol(s)			Name of each exchange on which registered
Common Stock, $0.01 par value per share			AEE			New York Stock Exchange

---

Table of Contents

Indicate by check mark whether each registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.

Ameren Corporation

Yes

☒

No

☐

Union Electric Company

Yes

☒

No

☐

Ameren Illinois Company

Yes

☒

No

☐

Indicate by check mark whether each registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).

Ameren Corporation

Yes

☒

No

☐

Union Electric Company

Yes

☒

No

☐

Ameren Illinois Company

Yes

☒

No

☐

Indicate by check mark whether each registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Ameren Corporation

Large accelerated filer

☒

Accelerated filer

☐

Non-accelerated filer

☐

Smaller reporting company

☐

Emerging growth company

☐

Union Electric Company

Large accelerated filer

☐

Accelerated filer

☐

Non-accelerated filer

☒

Smaller reporting company

☐

Emerging growth company

☐

Ameren Illinois Company

Large accelerated filer

☐

Accelerated filer

☐

Non-accelerated filer

☒

Smaller reporting company

☐

Emerging growth company

☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

Ameren Corporation			☐
Union Electric Company			☐
Ameren Illinois Company			☐

Indicate by check mark whether each registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).

Ameren Corporation

Yes

☐

No

☒

Union Electric Company

Yes

☐

No

☒

Ameren Illinois Company

Yes

☐

No

☒

The number of shares outstanding of each registrant’s classes of common stock as of October 30, 2026, was as follows:

Registrant						Title of each class of common stock			Shares outstanding
Ameren Corporation						Common stock, $0.01 par value per share			276,937,491
Union Electric Company						Common stock, $5 par value per share, held by Ameren Corporation			102,123,834
Ameren Illinois Company						Common stock, no par value, held by Ameren Corporation			25,452,373

This combined Form 10-Q is separately filed by Ameren Corporation, Union Electric Company, and Ameren Illinois Company. Each registrant hereto is filing on its own behalf all of the information contained in this quarterly report that relates to such registrant. Each registrant hereto is not filing any information that does not relate to such registrant, and therefore makes no representation as to any such information.

---

Table of Contents

TABLE OF CONTENTS

						Page
Glossary of Terms and Abbreviations						1
Forward-looking Statements						1
PART I. Financial Information
Item 1.			Financial Statements (Unaudited)			4
			Ameren Corporation			4
			Consolidated Statement of Income and Comprehensive Income			4
			Consolidated Balance Sheet			5
			Consolidated Statement of Cash Flows			6
			Consolidated Statement of Shareholders’ Equity			7
			Union Electric Company (d/b/a Ameren Missouri)			8
			Consolidated Statement of Income			8
			Consolidated Balance Sheet			9
			Consolidated Statement of Cash Flows			10
			Consolidated Statement of Shareholders’ Equity			11
			Ameren Illinois Company (d/b/a Ameren Illinois)			12
			Statement of Income			12
			Balance Sheet			13
			Statement of Cash Flows			14
			Statement of Shareholders’ Equity			15
			Note 1. Summary of Significant Accounting Policies			16
			Note 2. Rate and Regulatory Matters			17
			Note 3. Short-term Debt and Liquidity			20
			Note 4. Long-term Debt and Equity Financings			21
			Note 5. Other Income, Net			24
			Note 6. Derivative Financial Instruments			24
			Note 7. Fair Value Measurements			26
			Note 8. Related-party Transactions			29
			Note 9. Commitments and Contingencies			30
			Note 10. Callaway Energy Center			33
			Note 11. Retirement Benefits			34
			Note 12. Income Taxes			35
			Note 13. Supplemental Information			36
			Note 14. Segment Information			38
Item 2.			Management’s Discussion and Analysis of Financial Condition and Results of Operations			45
Item 3.			Quantitative and Qualitative Disclosures About Market Risk			78
Item 4.			Controls and Procedures			78
PART II. Other Information
Item 1.			Legal Proceedings			78
Item 1A.			Risk Factors			78
Item 2.			Unregistered Sales of Equity Securities and Use of Proceeds			78
Item 5.			Other Information			78
Item 6.			Exhibits			80
Signatures						81

---

Table of Contents

GLOSSARY OF TERMS AND ABBREVIATIONS

We use the words “our,” “we” or “us” with respect to certain information that relates to Ameren, Ameren Missouri, and Ameren Illinois, collectively. When appropriate, subsidiaries of Ameren Corporation are named specifically as their various business activities are discussed. Refer to the Form 10-K for a complete listing of glossary terms and abbreviations. Only new or significantly changed terms and abbreviations are included below.

2026 PRP – Ameren Missouri’s preferred resource plan for meeting customers’ projected long-term energy needs, which was filed with the MoPSC in September 2026 as a part of its integrated resource plan.

Form 10-K – The combined Annual Report on Form 10-K for the year ended December 31, 2025, filed by the Ameren Companies with the SEC.

QTD – Three months ended September 30.

YTD – Nine months ended September 30.

YoY – Compared with the year-ago period.

FORWARD-LOOKING STATEMENTS

Statements in this report not based on historical facts are considered “forward-looking” and, accordingly, involve risks and uncertainties that could cause actual results to differ materially from those discussed. Although such forward-looking statements have been made in good faith and are based on reasonable assumptions, there is no assurance that the expected results will be achieved. These statements include (without limitation) statements as to future expectations, beliefs, plans, projections, strategies, targets, estimates, objectives, events, conditions, and financial performance. In connection with the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, we are providing this cautionary statement to identify important factors that could cause actual results to differ materially from those anticipated. The following factors, in addition to those discussed within Risk Factors in the Form 10-K, and elsewhere in this report and in our other filings with the SEC, could cause actual results to differ materially from management expectations suggested in such forward-looking statements:

•regulatory, judicial, or legislative actions, and any changes in regulatory policies and ratemaking determinations that may change regulatory recovery mechanisms or our ability to recover costs and earn a return, such as those that may result from Ameren Missouri’s electric service regulatory rate review filed with the MoPSC in June 2026, Ameren Illinois’ 2025 electric distribution service revenue requirement reconciliation adjustment review filed with the ICC in April 2026, Ameren Illinois’ January 2026 appeal of the November 2025 ICC order issued in the 2025 natural gas delivery service rate review, and Ameren Illinois’ 2020 QIP reconciliation hearing;

•our ability to control costs and make necessary investments in our businesses, including our ability to recover costs and investments, and to earn our allowed ROEs, within frameworks established by our regulators, while maintaining affordability for our customers;

•the effect and duration of Ameren Illinois’ election to utilize a four-year MYRP for electric distribution service ratemaking, including the effect of the reconciliation cap on the electric distribution revenue requirement;

•the effect on Ameren Missouri of any customer rate caps or limitations on increasing the electric service revenue requirement pursuant to Ameren Missouri’s election to use the PISA;

•Ameren Missouri’s ability to construct and/or acquire generation and battery energy storage facilities, extend the operating license for the Callaway Energy Center, reliably operate existing energy centers through their expected retirement dates, retire fossil fuel-fired energy centers, and implement new or existing customer energy-efficiency programs, in each case in accordance with its Smart Energy Plan and preferred resource plan, and to recover its cost of investment, a related return, and, in the case of customer energy-efficiency programs, any lost electric revenues in a timely manner, each of which is affected by the ability to timely obtain and maintain all necessary regulatory and project approvals, including CCNs from the MoPSC or any other required approvals, including permits to construct and operate the facilities;

•our ability to realize and support forecasted energy demand and capacity from new and potential new customers, including demand growth dependent on the addition of new data centers and other large primary service customers within our service territories, such as the large load customers that signed electric service agreements with Ameren Missouri in 2026;

•the effects on energy prices and demand for our services resulting from customer growth patterns or usage, including demand from data centers; technological advances, including advances in customer energy efficiency; electric vehicles; electrification of various industries; energy storage; and private generation sources, which are becoming increasingly cost-competitive;

•Ameren Missouri’s ability to earn, utilize, or transfer at a reasonable price federal production and investment tax credits related to renewable energy, energy storage, and nuclear energy; the cost of wind, solar, and other renewable generation and battery energy storage technologies; and our ability to obtain timely interconnection agreements with the MISO or other RTOs at an acceptable cost for each facility;

•the effect of changes in federal domestic energy policy to support investment in fossil fuel infrastructure and the effect of those changes on Ameren Missouri’s ability to construct and/or acquire renewable energy generation facilities and battery energy storage;

1

---

Table of Contents

•the results of the MISO long-range transmission planning process, including potential changes to planned projects, the ability to obtain competitively bid or assigned projects and related approvals, including CCNs from the MoPSC and ICC or any other required approvals, and changes in applicable legislative or regulatory frameworks;

•the ability of our counterparties to meet their obligations with respect to contracts, credit agreements, and financial instruments, including as they relate to the construction and acquisition of electric and natural gas utility infrastructure, and the ability of counterparties to complete projects, which is dependent upon the availability of labor and necessary materials and equipment, including those obligations that are affected by supply chain disruptions;

•advancements in energy technologies, including carbon capture, utilization, and sequestration, hydrogen fuel for electric production and energy storage, next generation nuclear, and large-scale long-cycle battery energy storage, and the impact of federal and state energy and economic policies with respect to those technologies;

•the effects of changes in federal, state, or local laws and other domestic or international governmental actions, including monetary, fiscal, foreign trade, and energy policies, foreign trade tariffs, executive orders, geopolitical developments, or extended federal government shutdowns or defunding;

•the effects of changes in federal, state, or local tax laws or rates; additional regulations, interpretations, amendments, or technical corrections to, or in connection with the OBBBA and the IRA, including the effects of the OBBBA as it relates to construction timelines of solar, wind, and battery energy storage projects, along with the ability to obtain materials for these projects to be eligible for federal production and investment tax credits; and any challenges to the tax positions taken by the Ameren Companies, as well as resulting effects on customer rates;

•the cost and availability of fuel, such as low-sulfur coal, natural gas, and enriched uranium used to produce electricity; the cost and availability of natural gas for distribution and the cost and availability of purchased power, including capacity, zero emission credits, renewable energy credits, and emission allowances; and the level and volatility of future market prices for such commodities and credits;

•disruptions in the delivery of fuel, failure of our fuel suppliers to provide adequate quantities or quality of fuel, or lack of adequate inventories of fuel, including nuclear fuel assemblies primarily from the one NRC-licensed supplier of assemblies for Ameren Missouri’s Callaway Energy Center;

•the cost and availability of transmission capacity required for the energy generated by Ameren Missouri’s energy centers or as required to satisfy our energy sales;

•the effectiveness of our risk management strategies and our use of financial and derivative instruments;

•the ability to obtain sufficient insurance at a reasonable cost, or, in the absence of insurance, the ability to timely recover uninsured losses from our customers;

•the impact of cyberattacks and data security risks on us, our suppliers, or other entities on the grid, including those arising from generative or agentic artificial intelligence, which could, among other things, result in the loss of operational control of energy centers and electric and natural gas transmission and distribution systems and/or the loss of data, such as customer, employee, financial, and operating system information;

•acts of sabotage, which have increased in frequency and severity within the utility industry, war, terrorism, or other intentionally disruptive acts;

•business, economic, geopolitical, and capital market conditions, including foreign trade tariffs or trade wars, evolving federal regulatory priorities, and the impact of such conditions on interest rates, inflation, commodity prices, and investments;

•the impact of inflation or a recession on our customers and suppliers and the related impact on our results of operations, financial position, and liquidity;

•disruptions of the capital and credit markets, deterioration in credit metrics of the Ameren Companies, or other events that may have an adverse effect on the cost or availability of capital, including short-term credit and liquidity, and our ability to access the capital and credit markets on reasonable terms when needed;

•the actions of credit rating agencies and the effects of such actions;

•the impact of weather conditions and other natural conditions on us and our customers, including the impact of system outages and the level of wind and solar resources;

•the financing, construction, installation, performance, and cost recovery of generation, transmission, and distribution assets;

•the ability to maintain system reliability by Ameren Missouri, the MISO, and the electric utility industry, as well as Ameren Missouri’s ability to meet existing or future generation capacity and power obligations;

•the effects of failures of electric generation, electric and natural gas transmission or distribution, or natural gas storage facilities systems and equipment, which could result in unanticipated liabilities or unplanned outages;

•the operation of Ameren Missouri’s Callaway Energy Center, including planned and unplanned outages, as well as the ability to recover costs associated with such outages and the impact of such outages on off-system sales and purchased power, among other things;

•Ameren Missouri’s ability to recover the remaining investment and decommissioning costs associated with the retirement of an energy center, as well as the ability to earn a return on that remaining investment and those decommissioning costs;

•the impact of current environmental laws or their interpretation and new, more stringent, or changing requirements and environmental policies, including those related to NSR, CO2, NOx, SO2, and other emissions and discharges, Illinois emission standards, cooling water intake structures, CCR, energy efficiency, and wildlife protection, that could limit, terminate or otherwise modify the operation of certain

2

---

Table of Contents

of Ameren Missouri’s energy centers, increase our operating costs or investment requirements, result in an impairment of our assets, cause us to sell our assets, reduce our customers’ demand for electricity or natural gas, or otherwise have a negative financial effect;

•the impact of complying with renewable energy standards in Missouri and Illinois and with the zero emission standard in Illinois;

•the effectiveness of Ameren Missouri’s customer energy-efficiency programs and the related revenues and performance incentives earned under its MEEIA programs;

•labor disputes, the impact of collective bargaining unit contract negotiations, workforce reductions, our ability to attract and retain professional and skilled-craft employees, changes in future wage and employee benefits costs, including those resulting from changes in discount rates, mortality tables, medical cost trend rates, returns on benefit plan assets, and other assumptions;

•the impact of negative opinions of us or our utility services that our customers, investors, legislators, regulators, creditors, rating agencies, or other stakeholders may have or develop, which could result from a variety of factors, including failures in system reliability, failure to implement our investment plans or disagreement with those plans, failure to protect sensitive customer information, increases in rates, data centers entering our service territories, negative media coverage, or concerns about company policies or practices;

•the impact of adopting new accounting and reporting guidance;

•the effects of strategic initiatives, including mergers, acquisitions, joint ventures, divestitures, and reorganizations;

•legal and administrative proceedings;

•pandemics or other significant global health events, and their impacts on our results of operations, financial position, and liquidity; and

•the impacts of global conflicts and related sanctions imposed by the United States and other governments, including potential impacts on the cost and availability of fuel, natural gas, enriched uranium, and other commodities, materials, and services.

New factors emerge from time to time, and it is not possible for management to predict all of such factors, nor can it assess the impact of each such factor on the business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained or implied in any forward-looking statement. Given these uncertainties, undue reliance should not be placed on these forward-looking statements. Except to the extent required by the federal securities laws, we undertake no obligation to update or revise publicly any forward-looking statements to reflect new information or future events.

3

---

Table of Contents

PART I. FINANCIAL INFORMATION

ITEM 1. FINANCIAL STATEMENTS.

AMEREN CORPORATION

CONSOLIDATED STATEMENT OF INCOME AND COMPREHENSIVE INCOME

(Unaudited) (In millions, except per share amounts)

			Three Months Ended September 30,												Nine Months Ended September 30,
			2026						2025						2026						2025
Operating Revenues:
Electric			$	2,722					$	2,563					$	6,270					$	6,223
Natural gas			160						136						880						794
Total operating revenues			2,882						2,699						7,150						7,017
Operating Expenses:
Fuel and purchased power			809						768						1,749						2,064
Natural gas purchased for resale			28						25						238						233
Other operations and maintenance			535						502						1,547						1,447
Depreciation and amortization			436						415						1,254						1,168
Taxes other than income taxes			174						164						471						439
Total operating expenses			1,982						1,874						5,259						5,351
Operating Income			900						825						1,891						1,666
Other Income, Net			112						76						320						257
Interest Charges			216						208						629						570
Income Before Income Taxes			796						693						1,582						1,353
Income Taxes			119						52						231						145
Net Income			677						641						1,351						1,208
Less: Net Income Attributable to Noncontrolling Interests			1						1						4						4
Net Income Attributable to Ameren Common Shareholders			$	676					$	640					$	1,347					$	1,204
Earnings per Common Share - Basic			$	2.44					$	2.37					$	4.87					$	4.46
Earnings per Common Share – Diluted			$	2.42					$	2.35					$	4.83					$	4.43
Weighted-average Common Shares Outstanding – Basic			276.8						270.4						276.7						270.2
Weighted-average Common Shares Outstanding – Diluted			278.9						272.2						278.7						271.7
Net Income			$	677					$	641					$	1,351					$	1,208
Other Comprehensive Income (Loss), Net of Taxes
Pension and other postretirement benefit plan activity, net of income taxes (benefit) of $—, $—,$—, and $(1), respectively			1						—						—						(2)
Unrealized net gains (losses) on derivative hedging instruments, net of income taxes (benefit) of $11, $—, $12, and $(1), respectively			34						—						38						(6)
Comprehensive Income			712						641						1,389						1,200
Less: Comprehensive Income Attributable to Noncontrolling Interests			1						1						4						4
Comprehensive Income Attributable to Ameren Common Shareholders			$	711					$	640					$	1,385					$	1,196

The accompanying notes are an integral part of these consolidated financial statements.

4

---

Table of Contents

AMEREN CORPORATION

CONSOLIDATED BALANCE SHEET

(Unaudited) (In millions, except per share amounts)

			September 30, 2026						December 31, 2025
ASSETS
Current Assets:
Cash and cash equivalents			$	40					$	13
Accounts receivable – trade (less allowance for doubtful accounts of $47 and $39, respectively)			853						665
Unbilled revenue			511						415
Miscellaneous accounts receivable			238						107
Inventories			873						774
Current regulatory assets			275						387
Other current assets			329						210
Total current assets			3,119						2,571
Property, Plant, and Equipment, Net			42,239						39,313
Investments and Other Assets:
Nuclear decommissioning trust fund			1,638						1,526
Goodwill			411						411
Regulatory assets (includes $426 and $443 related to VIEs, respectively)			2,964						2,524
Pension and other postretirement benefits			1,000						977
Other assets			1,396						1,154
Total investments and other assets			7,409						6,592
TOTAL ASSETS			$	52,767					$	48,476
LIABILITIES AND EQUITY
Current Liabilities:
Current maturities of long-term debt (includes $24 and $23 related to VIEs, respectively)			$	1,574					$	973
Short-term debt			496						643
Accounts and wages payable			976						1,254
Taxes accrued			235						66
Interest accrued			199						229
Customer deposits			244						238
Other current liabilities			469						504
Total current liabilities			4,193						3,907
Long-term Debt, Net (includes $414 and $426 related to VIEs, respectively)			20,443						18,214
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes and tax credits, net			5,646						5,181
Regulatory liabilities			6,606						6,255
Asset retirement obligations			863						849
Other deferred credits and liabilities			680						540
Total deferred credits and other liabilities			13,795						12,825
Commitments and Contingencies (Notes 2, 9, and 10)
Shareholders’ Equity:
Common stock, $.01 par value, 400.0 shares authorized – shares outstanding of 276.9 and 276.4, respectively			3						3
Other paid-in capital, principally premium on common stock			8,149						8,106
Retained earnings			6,017						5,292
Accumulated other comprehensive income			38						—
Total shareholders’ equity			14,207						13,401
Noncontrolling Interests			129						129
Total equity			14,336						13,530
TOTAL LIABILITIES AND EQUITY			$	52,767					$	48,476

The accompanying notes are an integral part of these consolidated financial statements.

5

---

Table of Contents

AMEREN CORPORATION
CONSOLIDATED STATEMENT OF CASH FLOWS
(Unaudited) (In millions)
			Nine Months Ended September 30,
			2026						2025
Cash Flows From Operating Activities:
Net income			$	1,351					$	1,208
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			1,277						1,199
Amortization of nuclear fuel			63						39
Amortization of debt issuance costs and premium/discounts			15						14
Deferred income taxes and tax credits, net			281						255
Allowance for equity funds used during construction			(104)						(60)
Stock-based compensation costs			24						21
Other			(7)						29
Changes in assets and liabilities:
Receivables			(411)						(356)
Inventories			(97)						(41)
Accounts and wages payable			(138)						(244)
Taxes accrued			156						307
Regulatory assets and liabilities			(220)						97
Assets, other			(48)						(29)
Liabilities, other			130						72
Pension and other postretirement benefits			(79)						(114)
Net cash provided by operating activities			2,193						2,397
Cash Flows From Investing Activities:
Capital expenditures			(4,089)						(3,118)
Nuclear fuel expenditures			(26)						(20)
Purchases of securities – nuclear decommissioning trust fund			(513)						(373)
Sales and maturities of securities – nuclear decommissioning trust fund			488						348
Other			(14)						51
Net cash used in investing activities			(4,154)						(3,112)
Cash Flows From Financing Activities:
Dividends on common stock			(622)						(576)
Dividends paid to noncontrolling interest holders			(4)						(4)
Short-term debt, net			(147)						(239)
Maturities and extinguishment of long-term debt			(378)						(324)
Issuances of long-term debt			3,234						1,960
Issuances of common stock			31						35
Employee payroll taxes related to stock-based compensation			(14)						(13)
Debt issuance costs			(34)						(17)
Net cash provided by financing activities			2,066						822
Net change in cash, cash equivalents, and restricted cash			105						107
Cash, cash equivalents, and restricted cash at beginning of year			420						328
Cash, cash equivalents, and restricted cash at end of period			$	525					$	435

The accompanying notes are an integral part of these consolidated financial statements.

6

---

Table of Contents

AMEREN CORPORATION

CONSOLIDATED STATEMENT OF SHAREHOLDERS’ EQUITY

(Unaudited) (In millions, except per share amounts)

			Three Months Ended September 30,												Nine Months Ended September 30,
			2026						2025						2026						2025
Common Stock			$	3					$	3					$	3					$	3
Other Paid-in Capital:
Beginning of period			8,132						7,541						8,106						7,513
Shares issued under the DRPlus and 401(k) plan			8						10						30						35
Stock-based compensation activity			9						8						13						11
Other paid-in capital, end of period			8,149						7,559						8,149						7,559
Retained Earnings:
Beginning of period			5,549						4,784						5,292						4,604
Net income attributable to Ameren common shareholders			676						640						1,347						1,204
Dividends on common stock			(208)						(192)						(622)						(576)
Retained earnings, end of period			6,017						5,232						6,017						5,232
Accumulated Other Comprehensive Income (Loss):
Derivative financial instruments, beginning of period			10						(3)						6						3
Change in derivative financial instruments			34						—						38						(6)
Derivative financial instruments, end of period			44						(3)						44						(3)
Deferred retirement benefit costs, beginning of period			(7)						(11)						(6)						(9)
Change in deferred retirement benefit costs			1						—						—						(2)
Deferred retirement benefit costs, end of period			(6)						(11)						(6)						(11)
Total accumulated other comprehensive income (loss), end of period			38						(14)						38						(14)
Total Shareholders’ Equity			$	14,207					$	12,780					$	14,207					$	12,780
Noncontrolling Interests:
Beginning of period			129						129						129						129
Net income attributable to noncontrolling interest holders			1						1						4						4
Dividends paid to noncontrolling interest holders			(1)						(1)						(4)						(4)
Noncontrolling interests, end of period			129						129						129						129
Total Equity			$	14,336					$	12,909					$	14,336					$	12,909
Common stock shares outstanding at beginning of period			276.8						270.4						276.4						269.9
Shares issued under the DRPlus and 401(k) plan			0.1						0.1						0.3						0.3
Shares issued for stock-based compensation			—						—						0.2						0.3
Common stock shares outstanding at end of period			276.9						270.5						276.9						270.5
Dividends per common share			$	0.75					$	0.71					$	2.25					$	2.13

The accompanying notes are an integral part of these consolidated financial statements.

7

---

Table of Contents

UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI)

CONSOLIDATED STATEMENT OF INCOME

(Unaudited) (In millions)

			Three Months Ended September 30,												Nine Months Ended September 30,
			2026						2025						2026						2025
Operating Revenues:
Electric			$	1,757					$	1,685					$	3,702					$	3,893
Natural gas			24						20						133						109
Total operating revenues			1,781						1,705						3,835						4,002
Operating Expenses:
Fuel and purchased power			509						487						1,041						1,431
Natural gas purchased for resale			5						6						46						45
Other operations and maintenance			274						260						820						748
Depreciation and amortization			246						239						694						642
Taxes other than income taxes			129						122						325						300
Total operating expenses			1,163						1,114						2,926						3,166
Operating Income			618						591						909						836
Other Income, Net			58						45						171						135
Interest Charges			82						85						247						215
Income Before Income Taxes			594						551						833						756
Income Taxes			11						32						15						43
Net Income			583						519						818						713
Preferred Stock Dividends			1						1						3						3
Net Income Available to Common Shareholder			$	582					$	518					$	815					$	710

The accompanying notes as they relate to Ameren Missouri are an integral part of these consolidated financial statements.

8

---

Table of Contents

UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI)

CONSOLIDATED BALANCE SHEET

(Unaudited) (In millions, except per share amounts)

			September 30, 2026						December 31, 2025
ASSETS
Current Assets:
Cash and cash equivalents			$	26					$	6
Accounts receivable – trade (less allowance for doubtful accounts of $19 and $17, respectively)			409						284
Accounts receivable – affiliates			14						15
Unbilled revenue			297						193
Miscellaneous accounts receivable			68						15
Inventories			549						492
Current regulatory assets			135						181
Other current assets			190						119
Total current assets			1,688						1,305
Property, Plant, and Equipment, Net			22,709						20,604
Investments and Other Assets:
Nuclear decommissioning trust fund			1,638						1,526
Regulatory assets (includes $426 and $443 related to VIEs, respectively)			1,610						1,450
Pension and other postretirement benefits			279						271
Other assets			352						244
Total investments and other assets			3,879						3,491
TOTAL ASSETS			$	28,276					$	25,400
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current Liabilities:
Current maturities of long-term debt (includes $24 and $23 related to VIEs, respectively)			$	424					$	23
Short-term debt			100						471
Accounts and wages payable			485						696
Accounts payable – affiliates			110						61
Taxes accrued			212						34
Interest accrued			95						99
Other current liabilities			193						178
Total current liabilities			1,619						1,562
Long-term Debt, Net (includes $414 and $426 related to VIEs, respectively)			9,072						8,120
Long-term Debt, Net - Related Parties			107						87
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes and tax credits, net			2,935						2,702
Regulatory liabilities			3,414						3,324
Asset retirement obligations			858						844
Other deferred credits and liabilities			329						184
Total deferred credits and other liabilities			7,536						7,054
Commitments and Contingencies (Notes 2, 8, 9, and 10)
Shareholders’ Equity:
Common stock, $5 par value, 150.0 shares authorized – 102.1 shares outstanding			511						511
Other paid-in capital, principally premium on common stock			3,779						3,229
Preferred stock			80						80
Retained earnings			5,572						4,757
Total shareholders’ equity			9,942						8,577
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY			$	28,276					$	25,400

The accompanying notes as they relate to Ameren Missouri are an integral part of these consolidated financial statements.

9

---

Table of Contents

UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI)

CONSOLIDATED STATEMENT OF CASH FLOWS

(Unaudited) (In millions)

			Nine Months Ended September 30,
			2026						2025
Cash Flows From Operating Activities:
Net income			$	818					$	713
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			717						673
Amortization of nuclear fuel			63						39
Amortization of debt issuance costs and premium/discounts			7						7
Deferred income taxes and tax credits, net			93						167
Allowance for equity funds used during construction			(80)						(37)
Other			9						7
Changes in assets and liabilities:
Receivables			(249)						(245)
Inventories			(55)						3
Accounts and wages payable			(158)						(240)
Taxes accrued			215						336
Regulatory assets and liabilities			(98)						(155)
Assets, other			(68)						21
Liabilities, other			93						26
Pension and other postretirement benefits			(25)						(42)
Net cash provided by operating activities			1,282						1,273
Cash Flows From Investing Activities:
Capital expenditures			(2,750)						(1,873)
Nuclear fuel expenditures			(26)						(20)
Purchases of securities – nuclear decommissioning trust fund			(513)						(373)
Sales and maturities of securities – nuclear decommissioning trust fund			488						348
Money pool advances, net			—						43
Other			(19)						—
Net cash used in investing activities			(2,820)						(1,875)
Cash Flows From Financing Activities:
Dividends on common stock			—						(125)
Dividends on preferred stock			(3)						(3)
Short-term debt, net			(371)						259
Money pool borrowings, net			—						51
Maturities of long-term debt			(12)						—
Issuances of long-term debt			1,395						500
Capital contribution from parent			550						—
Debt issuance costs			(15)						(4)
Net cash provided by financing activities			1,544						678
Net change in cash, cash equivalents, and restricted cash			6						76
Cash, cash equivalents, and restricted cash at beginning of year			68						17
Cash, cash equivalents, and restricted cash at end of period			$	74					$	93

The accompanying notes as they relate to Ameren Missouri are an integral part of these consolidated financial statements.

10

---

Table of Contents

UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI)

CONSOLIDATED STATEMENT OF SHAREHOLDERS’ EQUITY

(Unaudited) (In millions)

			Three Months Ended September 30,												Nine Months Ended September 30,
			2026						2025						2026						2025
Common Stock			$	511					$	511					$	511					$	511
Other Paid-in Capital
Beginning of period			3,654						3,201						3,229						3,201
Capital contributions from parent			125						—						550						—
Other paid-in capital, end of period			3,779						3,201						3,779						3,201
Preferred Stock			80						80						80						80
Retained Earnings:
Beginning of period			4,990						4,348						4,757						4,206
Net income			583						519						818						713
Dividends on common stock			—						(75)						—						(125)
Dividends on preferred stock			(1)						(1)						(3)						(3)
Retained earnings, end of period			5,572						4,791						5,572						4,791
Total Shareholders’ Equity			$	9,942					$	8,583					$	9,942					$	8,583

The accompanying notes as they relate to Ameren Missouri are an integral part of these consolidated financial statements.

11

---

Table of Contents

AMEREN ILLINOIS COMPANY (d/b/a AMEREN ILLINOIS)

STATEMENT OF INCOME

(Unaudited) (In millions)

			Three Months Ended September 30,												Nine Months Ended September 30,
			2026						2025						2026						2025
Operating Revenues:
Electric			$	917					$	829					$	2,432					$	2,203
Natural gas			136						117						748						686
Total operating revenues			1,053						946						3,180						2,889
Operating Expenses:
Purchased power			304						284						719						642
Natural gas purchased for resale			23						19						192						188
Other operations and maintenance			265						241						745						702
Depreciation and amortization			175						162						517						484
Taxes other than income taxes			42						38						133						126
Total operating expenses			809						744						2,306						2,142
Operating Income			244						202						874						747
Other Income, Net			25						30						80						101
Interest Charges			72						67						209						192
Income Before Income Taxes			197						165						745						656
Income Taxes			53						17						197						134
Net Income			144						148						548						522
Preferred Stock Dividends			—						—						1						1
Net Income Available to Common Shareholder			$	144					$	148					$	547					$	521

The accompanying notes as they relate to Ameren Illinois are an integral part of these financial statements.

12

---

Table of Contents

AMEREN ILLINOIS COMPANY (d/b/a AMEREN ILLINOIS)

BALANCE SHEET

(Unaudited) (In millions)

			September 30, 2026						December 31, 2025
ASSETS
Current Assets:
Cash and cash equivalents			$	11					$	3
Accounts receivable – trade (less allowance for doubtful accounts of $28 and $22, respectively)			426						364
Accounts receivable – affiliates			21						18
Unbilled revenue			214						222
Miscellaneous accounts receivable			140						56
Inventories			320						278
Prepaid assets			70						68
Current regulatory assets			135						189
Other current assets			16						6
Total current assets			1,353						1,204
Property, Plant, and Equipment, Net			17,173						16,567
Investments and Other Assets:
Goodwill			411						411
Regulatory assets			1,330						1,059
Pension and other postretirement benefits			582						570
Other assets			885						789
Total investments and other assets			3,208						2,829
TOTAL ASSETS			$	21,734					$	20,600
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current Liabilities:
Short-term debt			$	188					$	17
Accounts and wages payable			372						395
Accounts payable – affiliates			46						57
Interest accrued			61						69
Customer deposits			210						204
Mark-to-market derivative liabilities			60						45
Purchase of receivables liabilities			65						47
Current regulatory liabilities			49						132
Other current liabilities			126						135
Total current liabilities			1,177						1,101
Long-term Debt, Net			6,653						6,254
Long-term Debt, Net – Related Parties			5						5
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes and tax credits, net			2,489						2,354
Regulatory liabilities			3,023						2,775
Other deferred credits and liabilities			262						268
Total deferred credits and other liabilities			5,774						5,397
Commitments and Contingencies (Notes 2, 8, and 9)
Shareholders’ Equity:
Common stock, no par value, 45.0 shares authorized – 25.5 shares outstanding			—						—
Other paid-in capital			3,058						3,058
Preferred stock			49						49
Retained earnings			5,018						4,736
Total shareholders’ equity			8,125						7,843
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY			$	21,734					$	20,600

The accompanying notes as they relate to Ameren Illinois are an integral part of these financial statements.

13

---

Table of Contents

AMEREN ILLINOIS COMPANY (d/b/a AMEREN ILLINOIS)

STATEMENT OF CASH FLOWS

(Unaudited) (In millions)

			Nine Months Ended September 30,
			2026						2025
Cash Flows From Operating Activities:
Net income			$	548					$	522
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			517						484
Amortization of debt issuance costs and premium/discounts			3						3
Deferred income taxes and investment tax credits, net			115						30
Allowance for equity funds used during construction			(20)						(21)
Other			34						24
Changes in assets and liabilities:
Receivables			(166)						(129)
Inventories			(42)						(45)
Accounts and wages payable			28						(1)
Taxes accrued			(11)						26
Regulatory assets and liabilities			(124)						255
Assets, other			(16)						(49)
Liabilities, other			65						68
Pension and other postretirement benefits			(43)						(50)
Net cash provided by operating activities			888						1,117
Cash Flows From Investing Activities:
Capital expenditures			(1,088)						(1,127)
Money pool advances, net			—						(51)
Other			(2)						(3)
Net cash used in investing activities			(1,090)						(1,181)
Cash Flows From Financing Activities:
Dividends on common stock			(265)						(185)
Dividends on preferred stock			(1)						(1)
Short-term debt, net			171						(88)
Money pool borrowings, net			—						(37)
Maturities of long-term debt			—						(300)
Issuances of long-term debt			400						711
Debt issuance costs			(4)						(8)
Net cash provided by financing activities			301						92
Net change in cash, cash equivalents, and restricted cash			99						28
Cash, cash equivalents, and restricted cash at beginning of year			344						302
Cash, cash equivalents, and restricted cash at end of period			$	443					$	330

The accompanying notes as they relate to Ameren Illinois are an integral part of these financial statements.

14

---

Table of Contents

AMEREN ILLINOIS COMPANY (d/b/a AMEREN ILLINOIS)

STATEMENT OF SHAREHOLDERS’ EQUITY

(Unaudited) (In millions)

			Three Months Ended September 30,												Nine Months Ended September 30,
			2026						2025						2026						2025
Common Stock			$	—					$	—					$	—					$	—
Other Paid-in Capital			3,058						3,056						3,058						3,056
Preferred Stock			49						49						49						49
Retained Earnings:
Beginning of period			4,874						4,564						4,736						4,266
Net income			144						148						548						522
Dividends on common stock			—						(110)						(265)						(185)
Dividends on preferred stock			—						—						(1)						(1)
Retained earnings, end of period			5,018						4,602						5,018						4,602
Total Shareholders’ Equity			$	8,125					$	7,707					$	8,125					$	7,707

The accompanying notes as they relate to Ameren Illinois are an integral part of these financial statements.

15

---

Table of Contents

AMEREN CORPORATION (Consolidated)

UNION ELECTRIC COMPANY (Consolidated) (d/b/a Ameren Missouri)

AMEREN ILLINOIS COMPANY (d/b/a Ameren Illinois)

COMBINED NOTES TO FINANCIAL STATEMENTS

(Unaudited)

September 30, 2026

NOTE 1 – SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

General

Ameren, headquartered in St. Louis, Missouri, is a public utility holding company whose primary assets are its equity interests in its subsidiaries. Ameren’s subsidiaries are separate, independent legal entities with separate businesses, assets, and liabilities. Dividends on Ameren’s common stock and the payment of expenses by Ameren depend on distributions made to it by its subsidiaries. Ameren’s principal subsidiaries are listed below. Ameren also has other subsidiaries that conduct other activities, such as providing shared services.

•Union Electric Company, doing business as Ameren Missouri, operates a rate-regulated electric generation, transmission, and distribution business and a rate-regulated natural gas distribution business in Missouri.

•Ameren Illinois Company, doing business as Ameren Illinois, operates rate-regulated electric transmission, electric distribution, and natural gas distribution businesses in Illinois.

•ATXI operates a FERC rate-regulated electric transmission business in the MISO.

Ameren’s and Ameren Missouri’s financial statements are prepared on a consolidated basis and therefore include the accounts of their majority-owned subsidiaries. All intercompany transactions have been eliminated. Ameren Illinois has no subsidiaries. All tabular dollar amounts are in millions, unless otherwise indicated.

Note 1 – Summary of Significant Accounting Policies applies to the Ameren Companies. The remaining notes to the consolidated financial statements apply to the registrants as indicated in each footnote disclosure. Registrants are named specifically for their related activities and disclosures.

Our accounting policies conform to GAAP. Our financial statements reflect all adjustments (which include normal, recurring adjustments) that are necessary, in our opinion, for a fair statement of our results. The preparation of financial statements in conformity with GAAP requires management to make certain estimates and assumptions. Such estimates and assumptions affect reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the dates of financial statements, and the reported amounts of revenues and expenses during the reported periods. Actual results could differ from those estimates. The results of operations for an interim period may not give a true indication of results that may be expected for a full year. These financial statements contained in this Form 10-Q should be read in conjunction with the audited financial statements and accompanying notes included in the Form 10-K.

Variable Interest Entities

Variable Interest Entities that are Consolidated

AMF was formed in 2024 for the purpose of issuing and servicing securitized utility tariff bonds related to costs for the accelerated retirement of the Rush Island Energy Center. Ameren Missouri is the primary beneficiary of this entity because it has the power to direct the activities that most significantly impact the economic performance of the entity, as well as the obligation to absorb losses or the right to receive benefits from the entity that could potentially be significant to the variable interest entity. The entity is considered a variable interest entity primarily because its equity capitalization is insufficient to support its operations. The entity’s primary assets and liabilities are comprised of regulatory assets related to the unrecovered net plant balance associated with the retired energy center, among other costs, and long-term debt. Ameren and Ameren Missouri consolidate AMF, which Ameren Missouri wholly owns, and both manages and controls the entity’s operating activities.

16

---

Table of Contents

The following table presents the carrying values of AMF’s assets and liabilities included on Ameren’s and Ameren Missouri’s consolidated balance sheets as of September 30, 2026 and December 31, 2025:

						2026						2025
Unbilled revenue(a)						$	2					$	2
Other current assets(a)						26						21
Noncurrent regulatory assets(a)						426						443
Current maturities of long-term debt(b)						24						23
Interest accrued(b)						11						6
Current regulatory liabilities(c)						5						11
Long-term debt, net(b)						414						426

(a)Assets may be used only to meet AMF’s obligations and commitments.

(b)The securitized tariff bondholders have no recourse to Ameren Missouri.

(c)Included in “Other current liabilities” on Ameren’s and Ameren Missouri’s balance sheets.

Variable Interest Entities that are not Consolidated

As of September 30, 2026, and December 31, 2025, Ameren had unconsolidated variable interests in various equity method investments, primarily to advance innovative energy technologies, totaling $92 million and $64 million, respectively, included in “Other assets” on Ameren’s consolidated balance sheet. Any earnings or losses related to Ameren’s share in these investments are included in “Other Income, Net” on Ameren’s consolidated statement of income and comprehensive income. Ameren is not the primary beneficiary of these investments because it does not have the power to direct matters that most significantly affect the activities of these variable interest entities. As of September 30, 2026, Ameren’s maximum exposure to loss related to these variable interest entities is limited to the investment in these entities of $92 million plus associated outstanding funding commitments of $25 million.

COLI

Ameren (parent) and Ameren Illinois have COLI, which is recorded at the net cash surrender value. The net cash surrender value is the amount that can be realized under the insurance policies at the balance sheet date. As of September 30, 2026, the cash surrender value of COLI at Ameren and Ameren Illinois was $225 million (December 31, 2025 – $219 million) and $132 million (December 31, 2025 – $126 million), respectively, while total borrowings against the policies were $124 million (December 31, 2025 – $117 million) at both Ameren and Ameren Illinois. Ameren and Ameren Illinois have the right to offset the borrowings against the cash surrender value of the policies and, consequently, present the net asset in “Other assets” on their respective balance sheets. The net cash surrender value of Ameren’s COLI is affected by the investment performance of a separate account in which Ameren holds a beneficial interest.

Accounting and Reporting Developments

See Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of the Form 10-K for additional information about recently issued authoritative accounting standards related to internal-use software and government grants.

Accounting for Environmental Credit Programs

In May 2026, the FASB issued authoritative guidance that established requirements for the recognition, measurement, presentation, and disclosure of environmental credits and environmental credit obligations. The guidance applies to all entities that generate, purchase, or receive environmental credits, or that have a regulatory compliance obligation that may be settled with environmental credits. The guidance will be effective for the Ameren Companies beginning January 1, 2028. We are currently assessing the impacts of this guidance on our results of operations, financial position, and liquidity.

NOTE 2 – RATE AND REGULATORY MATTERS

Below is a summary of updates to significant regulatory proceedings and related legal proceedings. See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of the Form 10-K for additional information and a summary of our regulatory frameworks. We are unable to predict the ultimate outcome of these matters, the timing of final decisions of the various agencies and courts, or the impact on our results of operations, financial position, or liquidity.

17

---

Table of Contents

Missouri

2026 Electric Service Regulatory Rate Review

In June 2026, Ameren Missouri filed a request with the MoPSC seeking approval to increase its annual revenues for electric service by $343 million. The electric rate request is based on a 10.25% return on common equity, a capital structure composed of 52% common equity, a rate base of $16.7 billion, and a test year ended March 31, 2026, with certain pro-forma adjustments expected through an anticipated true-up date of December 31, 2026. Ameren Missouri also requested the continued use of all of its existing riders and trackers. The electric rate request reflects the following:

•increased transmission and distribution infrastructure investments to support system reliability and resiliency;

•investments in existing generation resources and 400 MWs of new generation resources; and

•the increase for the items above is partially offset by accelerating the benefits of investment tax credits to customers.

The MoPSC proceeding relating to the proposed electric service rate changes will take place over a period of up to 11 months, with a decision by the MoPSC expected by May 2027 and new rates effective by June 2027. Ameren Missouri cannot predict the level of any electric service rate change the MoPSC may approve, whether the requested regulatory recovery mechanisms will be continued, or whether any rate change that may eventually be approved will be sufficient for Ameren Missouri to recover its costs and earn a reasonable return on its investments when the rate change goes into effect.

Generation and Storage Facilities

Ameren Missouri is party to agreements to acquire and/or construct various generation and storage facilities that are consistent with the 2026 PRP. The generation and storage facilities are eligible for recovery under the PISA, subject to regulatory approval. The following table provides information about each facility:

Agreement type

Facility size

Status of MoPSC CCN

Status of FERC approval of acquisition

In-service date(a)

Bowling Green Solar Project(b)

Self-build

50-MW

Approved March 2024

Not applicable

March 2026

Split Rail Solar Project

Build-transfer(c)

300-MW

Approved March 2024

Received November 2024

June 2026

Castle Bluff Natural Gas Project(b)

Self-build

800-MW

Approved October 2024

Not applicable

Fourth quarter 2027

Big Hollow Battery Energy Storage Project(b)

Self-build

400-MW

Approved February 2026

Not applicable

Second quarter 2028

Big Hollow Natural Gas Project(b)

Self-build

800-MW

Approved February 2026

Not applicable

Third quarter 2028

Reform Solar Project(b)

Self-build

250-MW

Approved May 2026

Not applicable

Fourth quarter 2028

Castle Bluff Battery Energy Storage Project(b)

Self-build

95-MW

Approved October 2026

Not applicable

Second quarter 2028

Millcreek Battery Energy Storage Project(b)

Self-build

250-MW

Approved October 2026

Not applicable

Second quarter 2028

Huck Finn Battery Energy Storage Project(b)

Self-build

200-MW

Approved October 2026

Not applicable

Second quarter 2028

Tom Sawyer Solar Project(b)

Build-transfer

175-MW

Approved October 2026

Received September 2026

Fourth quarter 2028

Ringer Solar Project

Build-transfer

225-MW

Approved October 2026

Expect to request by mid-2027

Second quarter 2029

West Alton Natural Gas Project

Self-build

2,100-MW

Filed July 2026(d)

Not applicable

Fourth quarter 2031

(a)Future in-service dates, which were estimated in each CCN filing, are dependent on the timing of regulatory approvals and construction completion, among other things.

(b)These projects collectively represent approximately $5 billion of capital expenditures.

(c)In February 2026, Ameren Missouri acquired the Split Rail Solar Project for approximately $0.6 billion.

(d)Ameren Missouri expects a decision by the MoPSC in the first half of 2027.

18

---

Table of Contents

Illinois

MYRP

In December 2024, the ICC issued an order in connection with a revised Grid Plan and a revised MYRP filed by Ameren Illinois in March 2024, approving revenue requirements for electric distribution services for 2024 through 2027 of $1,206 million, $1,287 million, $1,367 million, and $1,421 million, respectively. In May 2026, the Illinois Appellate Court for the Fifth Judicial District upheld the ICC’s December 2024 order and orders issued by the ICC in June 2024 and December 2023 following appeals by Ameren Illinois.

2024 Electric Distribution Service Revenue Requirement Reconciliation Adjustment Order

In December 2025, the ICC issued an order approving Ameren Illinois’ 2024 electric distribution service revenue requirement reconciliation adjustment filing. In March 2026, Ameren Illinois filed an appeal of the December 2025 order with the Illinois Appellate Court for the Fifth Judicial District and withdrew the appeal in July 2026 as a result of the appellate court decision in the MYRP proceeding discussed above.

2025 Electric Distribution Service Revenue Requirement Reconciliation Adjustment Review

In April 2026, Ameren Illinois filed a reconciliation adjustment to its 2025 electric distribution service revenue requirement with the ICC. In August 2026, Ameren Illinois updated its reconciliation adjustment, requesting recovery of $28 million. The adjustment reflects Ameren Illinois’ actual 2025 recoverable costs, 2025 year-end rate base, and a capital structure composed of 50% common equity. The ICC staff has not objected to Ameren Illinois’ updated reconciliation adjustment. In November 2026, the administrative law judges issued a proposed order consistent with Ameren Illinois’ request. An ICC decision is required by December 2026, and any approved adjustment would be collected from customers in 2027.

Electric Energy Efficiency Plan

Pursuant to the CRGA, the annual spending cap for energy-efficiency investments increased for 2027, 2028, and 2029. As a result, in May 2026, Ameren Illinois filed an electric energy efficiency plan with the ICC, which includes annual investments in electric energy-efficiency programs up to $192 million, $239 million, and $276 million for 2027, 2028, and 2029, respectively. The ICC has the ability to reduce the amount of electric energy-efficiency savings goals in future program years if there are insufficient cost-effective programs available, which could reduce Ameren Illinois’ investments in electric energy-efficiency programs. A decision by the ICC in this proceeding is expected in November 2026.

2025 Natural Gas Delivery Service Rate Order

In November 2025, the ICC issued an order in Ameren Illinois’ January 2025 natural gas delivery service regulatory rate review, which resulted in an increase to Ameren Illinois’ annual revenues for natural gas delivery service of $79 million based on a 9.60% ROE, a capital structure composed of 50% common equity, a 2026 future test year, and a rate base of $3.2 billion. The order reflected a reduction of $75 million of planned distribution and transmission capital investments included in Ameren Illinois’ future test year request. The new rates became effective in December 2025.

In January 2026, Ameren Illinois filed an appeal of the ICC’s November 2025 order to the Illinois Appellate Court for the Fifth Judicial District. The appeal challenged the inclusion of the non-service cost component of the net periodic benefit income related to other postretirement benefits in the annual revenue requirement and the $75 million reduction of planned capital investments, among other things. The court is under no deadline to address the appeal, and Ameren Illinois cannot predict the ultimate outcome of the appeal.

QIP Reconciliation Hearing

Pursuant to Illinois law, 2014 was the first year of the QIP. In 2021, Ameren Illinois filed a request with the ICC to initiate a reconciliation proceeding of natural gas capital investments recovered under the QIP rider during 2020. Ameren Illinois recovered similar investments in each of the 2014 to 2019 annual reconciliations. In September 2024, the Illinois Attorney General’s office challenged the recovery of capital investments that were made during 2020, alleging that the ICC should disallow $30 million in natural gas capital investments as imprudent, unsupported, or ineligible to be recovered through the QIP, resulting in a potential over-recovery of an immaterial amount by Ameren Illinois in 2020. In 2023, and again in 2024, the ICC staff filed testimony that supports the prudence and reasonableness of the capital investments made during 2020. Ameren Illinois’ 2020 QIP rate recovery request under review by the ICC is within the rate increase limitations allowed by law. The ICC is under no deadline to issue an order in this proceeding. In addition, the 2021 through 2023 reconciliation proceedings are still ongoing. Ameren Illinois included $529 million of eligible natural gas capital investments in the QIP from 2021 to 2023. Ameren Illinois cannot predict the ultimate outcome of these regulatory proceedings.

19

---

Table of Contents

Federal

Transmission Rate Incentives

In 2024, the MISO approved a first set of second tranche projects related to its preliminary long-range transmission planning roadmap of projects through 2039. In 2026, the MISO awarded three competitive bid projects to ATXI and other joint owners that represent a total estimated investment of approximately $1.2 billion for ATXI, based on the MISO’s cost estimate. In August 2026, the FERC approved transmission rate incentives relating to two of these competitive bid projects. The incentives will allow construction work in progress to be included in rate base, thereby improving the timeliness of cash recovery, and will allow recovery of prudently incurred costs, subject to FERC approval, for any portion of the projects if they are abandoned for reasons beyond the control of ATXI. Since construction work in progress will be included in rate base and earn a return, ATXI will not capitalize allowance for funds used during construction on these projects.

FERC ROE Complaint Cases

Since November 2013, the allowed base ROE for FERC-regulated transmission rate base under the MISO tariff has been subject to customer complaint cases and has been changed by various FERC orders. In October 2024, the FERC issued an order, which decreased the allowed base ROE from 10.02% to 9.98% and required refunds, with interest, for the periods from November 2013 to February 2015 and from late September 2016 forward. In June 2026, the United States Court of Appeals for the District of Columbia Circuit dismissed and denied various appeals of the October 2024 FERC order.

NOTE 3 – SHORT-TERM DEBT AND LIQUIDITY

The liquidity needs of the Ameren Companies are supported through the use of available cash, drawings under committed credit agreements, commercial paper issuances, and, in the case of Ameren Missouri and Ameren Illinois, short-term affiliate borrowings. See Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of the Form 10-K for a description of our indebtedness provisions and other covenants as well as a description of money pool agreements.

Short-term Borrowings

The Missouri Credit Agreement and the Illinois Credit Agreement are available to support issuances under Ameren (parent)’s, Ameren Missouri’s, and Ameren Illinois’ commercial paper programs, respectively, subject to borrowing sublimits, and to support the issuance of letters of credit for the borrowers. As of September 30, 2026, based on commercial paper outstanding and letters of credit issued under the Credit Agreements, along with cash and cash equivalents, the net liquidity available to Ameren (parent), Ameren Missouri, and Ameren Illinois, collectively, was $2.7 billion, and does not include Ameren’s forward equity sale agreements discussed below in Note 4 – Long-term Debt and Equity Financings. The Ameren Companies were in compliance with the covenants in their Credit Agreements as of September 30, 2026. As of September 30, 2026, the ratios of consolidated indebtedness to consolidated total capitalization, calculated in accordance with the provisions of the Credit Agreements, were 61%, 49%, and 46% for Ameren, Ameren Missouri, and Ameren Illinois, respectively.

The following table presents commercial paper outstanding, net of issuance discounts, as of September 30, 2026, and December 31, 2025. There were no borrowings outstanding under the Credit Agreements as of September 30, 2026, or December 31, 2025.

			September 30, 2026									December 31, 2025
Ameren (parent)			$	208								$	155
Ameren Missouri			100									471
Ameren Illinois			188									17
Ameren consolidated			$	496								$	643

20

---

Table of Contents

The following table summarizes the activity and relevant interest rates for Ameren (parent)’s, Ameren Missouri’s, and Ameren Illinois’ commercial paper issuances under the Credit Agreements for the nine months ended September 30, 2026 and 2025:

						Ameren (parent)						Ameren Missouri						Ameren Illinois						Ameren Consolidated
2026
Average daily amount outstanding						$	662					$	314					$	166					$	1,142
Weighted-average interest rate						3.90		%				3.87		%				3.89		%				3.89		%
Peak amount outstanding during period(a)						$	1,073					$	1,360					$	503					$	1,996
Peak interest rate						4.08		%				4.08		%				4.08		%				4.08		%
2025
Average daily amount outstanding						$	637					$	245					$	130					$	1,012
Weighted-average interest rate						4.60		%				4.58		%				4.55		%				4.59		%
Peak amount outstanding during period(a)						$	1,139					$	650					$	425					$	1,603
Peak interest rate						4.75		%				4.72		%				4.70		%				4.75		%

(a)The timing of peak outstanding commercial paper issuances under the Credit Agreements varies by company. Therefore, the sum of individual company peak amounts may not equal the Ameren consolidated peak amount for the period.

Separate from the Credit Agreements, Ameren and its utility subsidiaries have uncommitted letter of credit agreements totaling $200 million. These agreements may be used solely to support the issuance of letters of credit. As of September 30, 2026, Ameren and Ameren Missouri had $73 million and $50 million of letters of credit outstanding under these agreements, respectively.

Separate from the Credit Agreements and the uncommitted letter of credit agreements discussed above, Ameren Missouri has an uncommitted letter of credit agreement totaling $75 million. This agreement may be used solely to support the issuance of letters of credit. As of September 30, 2026, Ameren Missouri had $61 million of letters of credit outstanding under this agreement.

Money Pools

Ameren has money pool agreements with and among its subsidiaries to coordinate and provide for certain short-term cash and working capital requirements. The average interest rate for borrowings under the utility money pool for the three and nine months ended September 30, 2026 was 3.90% and 3.89%, respectively (2025 – 4.53% and 4.56%). See Note 8 – Related-party Transactions for the amount of interest income and expense from the utility money pool agreements recorded by Ameren Missouri and Ameren Illinois for the three and nine months ended September 30, 2026 and 2025.

NOTE 4 – LONG-TERM DEBT AND EQUITY FINANCINGS

Ameren

For the three and nine months ended September 30, 2026, Ameren issued a total of 0.1 million and 0.3 million shares of common stock under its DRPlus and 401(k) plan, and received proceeds of $2 million and $24 million, respectively. As of September 30, 2026, Ameren had a receivable of $6 million related to issuances of common stock under its DRPlus and 401(k) plan. In addition, in the first quarter of 2026, Ameren issued 0.2 million shares of common stock valued at $25 million upon the settlement of stock-based compensation awards.

In May 2026, Ameren filed a Form S-3 registration statement with the SEC, registering the offering of 1.9 million shares of its common stock under the DRPlus, which expires in May 2029. Shares of common stock sold under the DRPlus are, at Ameren’s option, newly issued shares, treasury shares, or shares purchased in the open market or in privately negotiated contracts.

In August 2026, Ameren, Ameren Missouri, and Ameren Illinois filed a Form S-3 shelf registration statement with the SEC, registering the issuance of an unspecified amount of certain types of securities. This registration statement expires in August 2029.

Ameren has entered into an equity distribution sales agreement pursuant to which Ameren may offer and sell from time to time its common stock through an ATM program, which includes the ability to enter into forward sale agreements. In August 2026, Ameren increased the amount of common stock available for sale under the ATM program by $2 billion to a total of $5 billion. There were no shares issued under the ATM program during the nine months ended September 30, 2026. As of September 30, 2026, Ameren had approximately $2 billion of common stock remaining available for sale under the ATM program.

21

---

Table of Contents

Forward sale agreements for 13 million shares outstanding under the ATM program as of September 30, 2026, can be settled at Ameren’s discretion on or prior to dates ranging from January 19, 2028, to March 8, 2028. The initial forward sale price for the agreements ranged from $104.39 to $112.91, with an average initial forward sale price of $109.51. Additionally in May 2025, Ameren entered into forward sale agreements separate from the ATM program with multiple counterparties relating to 6.4 million shares of common stock. The forward sale agreements can be settled at Ameren’s discretion on or prior to January 15, 2027, and the initial forward sale price under these agreements was $91.89 per share. On a settlement date or dates, if Ameren elects to physically settle a forward sale agreement, Ameren will issue shares of common stock to the counterparties at the then-applicable forward sale price. Each initial forward sale price is subject to adjustment based on a floating interest rate factor equal to the overnight bank funding rate less a spread of 75 basis points, and will be subject to decrease on certain dates specified in the forward sale agreements by specified amounts related to expected dividends on shares of the common stock during the term of the forward sale agreements. If the overnight bank funding rate is less than or more than the spread on any day, the interest rate factor will result in a reduction or an increase, respectively, of the forward sale price. The forward sale agreements will be physically settled unless Ameren elects to settle in cash or to net share settle.

At September 30, 2026, Ameren could have settled the forward sale agreements with physical delivery of 19.4 million shares of common stock to the respective counterparties in exchange for cash of $2 billion. Alternatively, the forward sale agreements could have also been net settled at September 30, 2026, with the counterparties delivering approximately $80 million of cash or approximately 0.8 million shares of common stock to Ameren. In connection with the forward sale agreements outstanding at September 30, 2026, the various counterparties, or their affiliates, borrowed from third parties and sold 19.4 million shares of common stock. The gross sales price of these shares totaled $2 billion. Ameren does not receive any proceeds from such sales of borrowed shares. The forward sale agreements have been classified as equity transactions.

In October 2026, Ameren entered into forward sale agreements under the ATM program for 2.1 million shares of common stock. The October 2026 forward sales can be settled at Ameren’s discretion in or prior to March 2028. The average forward sale price was initially $99.59 for the October 2026 forward sale agreements.

In March 2026, Ameren (parent) issued $400 million of 5.00% senior unsecured notes due May 2036, with interest payable semiannually on May 15 and November 15 of each year, beginning November 15, 2026. Net proceeds from this issuance were used to repay a portion of Ameren’s short-term debt, including short-term debt incurred to refinance $350 million of 3.65% senior unsecured notes that matured in February 2026.

In September 2026, Ameren (parent) issued $900 million of junior subordinated notes due March 2057, with interest payable semiannually on March 15 and September 15 of each year, beginning March 15, 2027. Net proceeds from this issuance were used for general corporate purposes, including repayment of short-term debt. The junior subordinated notes will initially pay interest at a fixed annual rate of 6.45% until March 15, 2032. After that date, the interest rate will be reset every five years to the applicable five-year United States Treasury rate plus 1.868%, subject to a minimum rate of 6.45%.

In 2026, Ameren (parent) purchased first mortgage bonds issued by Ameren Missouri for $16 million. On a consolidated basis, Ameren (parent)’s repurchase of these first mortgage bonds was accounted for as a debt extinguishment and resulted in a pre-tax gain of $4 million, which is reflected in “Other Income, Net” on Ameren’s consolidated statement of income.

Ameren Missouri

In February 2026, Ameren Missouri issued $450 million of 4.80% first mortgage bonds due March 2036 and $450 million of 5.55% first mortgage bonds due March 2056. Interest is payable semiannually for both issuances on March 15 and September 15 of each year, beginning September 15, 2026. Net proceeds from the February 2026 issuances were used for capital expenditures and to repay short-term debt.

In June 2026, Ameren Missouri issued $500 million of 5.75% first mortgage bonds due September 2056, with interest payable semiannually on March 15 and September 15 of each year, beginning March 15, 2027. Net proceeds from this issuance were used to repay short-term debt.

Ameren Missouri received capital contributions totaling $125 million and $550 million, respectively, during the three and nine months ended September 30, 2026.

Ameren Illinois

In August 2026, Ameren Illinois issued $400 million of 5.50% first mortgage bonds due September 2036, with interest payable semiannually on March 15 and September 15 of each year, beginning March 15, 2027. Net proceeds from this issuance were used to repay short-term debt.

22

---

Table of Contents

ATXI

In August 2026, pursuant to a note purchase agreement, ATXI issued $140 million of 5.83% senior unsecured notes due August 2041, with interest payable semiannually on February 6 and August 6 of each year, beginning February 6, 2027, through a private placement offering exempt from registration under the Securities Act of 1933, as amended. Net proceeds from this issuance were used to repay short-term debt.

In August 2026, pursuant to a note purchase agreement, ATXI agreed to issue $160 million of 6.24% senior unsecured notes due January 2054, with interest payable semiannually on January 28 and July 28 of each year, beginning July 28, 2027, through a private placement offering exempt from registration under the Securities Act of 1933, as amended. ATXI expects to issue the notes and receive the proceeds in January 2027, which will be used to repay short-term debt.

Indenture Provisions and Other Covenants

See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10-K for a description of our indenture provisions and other covenants, as well as restrictions on the payment of dividends. At September 30, 2026, the Ameren Companies were in compliance with the provisions and covenants contained in their indentures and articles of incorporation, as applicable, and ATXI was in compliance with the provisions and covenants contained in its note purchase agreements.

Off-balance-sheet Arrangements

At September 30, 2026, none of the Ameren Companies had any material off-balance-sheet financing arrangements, other than their investment in unconsolidated variable interest entities, letters of credit, and the forward sale agreements relating to common stock. See Note 1 – Summary of Significant Accounting Policies for further detail concerning variable interest entities.

23

---

Table of Contents

NOTE 5 – OTHER INCOME, NET

The following table presents the components of “Other Income, Net” in the Ameren Companies’ statements of income for the three and nine months ended September 30, 2026 and 2025:

			Three Months												Nine Months
			2026						2025						2026						2025
Ameren:
Allowance for equity funds used during construction			$	35					$	21					$	104					$	60
Other interest income			8						10						24						31
Non-service cost components of net periodic benefit income(a)			45						59						143						187
Miscellaneous income			7						6						17						13
Gain on extinguishment of debt(b)			—						—						4						8
Earnings (losses) related to equity method investments			24						(9)						48						(19)
Donations			(1)						(6)						(5)						(9)
Miscellaneous expense			(6)						(5)						(15)						(14)
Total Other Income, Net			$	112					$	76					$	320					$	257
Ameren Missouri:
Allowance for equity funds used during construction			$	27					$	14					$	80					$	37
Other interest income			3						3						8						7
Non-service cost components of net periodic benefit income(a)			30						29						89						96
Miscellaneous income			3						4						5						6
Donations			(1)						(2)						(3)						(4)
Miscellaneous expense			(4)						(3)						(8)						(7)
Total Other Income, Net			$	58					$	45					$	171					$	135
Ameren Illinois:
Allowance for equity funds used during construction			$	6					$	6					$	20					$	21
Other interest income			5						7						16						24
Non-service cost components of net periodic benefit income			12						21						41						61
Miscellaneous income			4						2						11						7
Donations			—						(4)						(2)						(5)
Miscellaneous expense			(2)						(2)						(6)						(7)
Total Other Income, Net			$	25					$	30					$	80					$	101

(a)For the three and nine months ended September 30, 2026, the non-service cost components of net periodic benefit income were adjusted by amounts deferred of $(19) million and $(59) million, respectively, due to a regulatory tracking mechanism for the difference between the level of such costs incurred by Ameren Missouri under GAAP and the level of such costs included in rates. The deferral was $(9) million and $(41) million, respectively, for the three and nine months ended September 30, 2025. See Note 11 – Retirement Benefits for additional information.

(b)See Note 4 – Long-term Debt and Equity Financings above and Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10-K for additional information on Ameren (parent)’s repurchase of Ameren Missouri’s senior secured notes and first mortgage bonds and Ameren Illinois’ first mortgage bonds that were accounted for as a debt extinguishment.

24

---

Table of Contents

NOTE 6 – DERIVATIVE FINANCIAL INSTRUMENTS

We use derivatives to manage the risk of changes in market prices for natural gas, power, and interest rates, as well as the risk of changes in rail transportation surcharges through fuel oil hedges. Such price fluctuations may cause the following:

•an unrealized appreciation or depreciation of our contracted commitments to purchase or sell when purchase or sale prices under the commitments are compared with current commodity prices;

•market values of natural gas that differ from the cost of this commodity in inventory;

•actual cash outlays for interest expense and the purchase of commodities that differ from anticipated cash outlays; and

•actual off-system sales revenues that differ from anticipated revenues.

The derivatives that we use to hedge these risks are governed by our risk management policies for forward contracts, futures, options, and swaps. Our net positions are continually assessed within our structured hedging programs to determine whether new or offsetting transactions are required. The goal of the hedging program is generally to mitigate financial risks while ensuring that sufficient volumes are available to meet our requirements. Contracts we enter into as part of our risk management program may be settled financially, settled by physical delivery, or net settled with the counterparty.

All contracts considered to be derivative instruments are required to be recorded on the balance sheet at their fair values, unless the NPNS exception applies. Many of our physical contracts, such as our purchased power contracts, qualify for the NPNS exception to derivative accounting rules. The revenue or expense on NPNS contracts is recognized at the contract price upon physical delivery. The following disclosures exclude NPNS contracts and other non-derivative commodity contracts that are accounted for under the accrual method of accounting.

If we determine that a contract meets the definition of a derivative and is not eligible for the NPNS exception, we review the contract to determine whether the resulting gains or losses qualify for regulatory deferral. Derivative contracts that qualify for regulatory deferral are recorded at fair value, with changes in fair value recorded as regulatory assets or liabilities in the period in which the change occurs. We believe derivative losses and gains deferred as regulatory assets and liabilities are probable of recovery, or refund, through future rates charged to customers. Regulatory assets and liabilities are amortized to operating income as related losses and gains are reflected in rates charged to customers. Therefore, gains and losses on these derivatives have no effect on operating income. As of September 30, 2026, and December 31, 2025, all commodity contracts that met the definition of a derivative and were not eligible for the NPNS exception received regulatory deferral. Interest rate hedges entered into by Ameren (parent) and discussed below do not receive regulatory deferral and were included in accumulated OCI as Ameren (parent) is not a rate-regulated entity. The cash flows from our derivative financial instruments follow the cash flow classification of the hedged item.

Ameren (parent) entered into interest rate swaps to hedge interest rate risk on certain forecasted interest payments associated with debt issuances in 2026 and 2027. The interest rate swaps are designated as cash flow hedges and the corresponding changes in fair value each period are initially recorded on the balance sheet in “Accumulated other comprehensive income (loss)” and reclassified into earnings when the debt is issued and the corresponding interest payments affect earnings during the debt term. As of September 30, 2026, and December 31, 2025, Ameren had unsettled interest rate swaps with notional amounts of $490 million and $820 million, respectively. Ameren recorded unrealized net gains (losses), net of income taxes (benefit), on the change in fair value of interest rate swaps of $34 million and $38 million for the three and nine months ended September 30, 2026 and less than $(1) million and $(6) million for the three and nine months ended September 30, 2025 to “Accumulated other comprehensive income (loss).” The gains (losses) reclassified out of “Accumulated other comprehensive income (loss)” to “Interest Charges” for the three and nine months ended September 30, 2026 were immaterial.

The following table presents open gross commodity contract volumes by commodity type for derivative assets and liabilities as of September 30, 2026, and December 31, 2025. As of September 30, 2026, these contracts extended through October 2029, October 2032, and May 2032 for fuel oils, natural gas, and power, respectively.

			Quantity (in millions, except as indicated)
			September 30, 2026									December 31, 2025
Commodity			Ameren Missouri			Ameren Illinois			Ameren			Ameren Missouri			Ameren Illinois			Ameren
Fuel oils (in gallons)			20			—			20			25			—			25
Natural gas (in MMBtu)			56			209			265			46			217			263
Power (in MWhs)			10			6			16			—			7			7

25

---

Table of Contents

The following table presents the carrying value and balance sheet location of all derivative commodity contracts, none of which were designated as hedging instruments because all qualify for regulatory deferral, as of September 30, 2026, and December 31, 2025:

									September 30, 2026																								December 31, 2025
Commodity			Balance Sheet Location						Ameren Missouri									Ameren Illinois									Ameren												Ameren Missouri									Ameren Illinois									Ameren
Fuel oils			Other current assets						$	15								$	—								$	15											$	—								$	—								$	—
			Other assets						6									—									6												—									—									—
Natural gas			Other current assets						—									2									2												1									1									2
			Other assets						1									3									4												—									3									3
Power			Other current assets						14									1									15												11									—									11
			Other assets						61									4									65												—									—									—
			Total assets						$	97								$	10								$	107											$	12								$	4								$	16
Fuel oils			Other current liabilities						$	—								$	—								$	—											$	3								$	—								$	3
			Other deferred credits and liabilities						—									—									—												2									—									2
Natural gas			Mark-to-market derivative liabilities						(a)									30									(a)												(a)									21									(a)
			Other current liabilities						7									—									37												5									—									26
			Other deferred credits and liabilities						5									8									13												5									11									16
Power			Mark-to-market derivative liabilities						(a)									30									(a)												(a)									24									(a)
			Other current liabilities						2									—									32												—									—									24
			Other deferred credits and liabilities						—									18									18												—									55									55
			Total liabilities						$	14								$	86								$	100											$	15								$	111								$	126

(a) Balance sheet line item not applicable to registrant.

The Ameren Companies elect to present the fair value amounts of derivative assets and derivative liabilities subject to an enforceable master netting arrangement or similar agreement at the gross amounts on the balance sheet. However, if the gross amounts recognized on the balance sheet were netted with derivative instruments and cash collateral received or posted, the net amounts would not be materially different from the gross amounts at September 30, 2026, and December 31, 2025.

Credit Risk

In determining our concentrations of credit risk related to derivative instruments, we review our individual counterparties and categorize each counterparty into groupings according to the primary business in which each engages. As of September 30, 2026, if counterparty groups were to fail completely to perform on contracts, the Ameren Companies’ maximum exposure related to derivative assets would have been immaterial with or without consideration of the application of master netting arrangements or similar agreements and collateral held.

Certain of our derivative instruments contain collateral provisions tied to the Ameren Companies’ credit ratings. If our credit ratings were downgraded below investment grade, or if a counterparty with reasonable grounds for uncertainty regarding our ability to satisfy an obligation requested adequate assurance of performance, additional collateral postings might be required. The additional collateral required is the net liability position allowed under master netting arrangements or similar agreements, assuming (1) the credit risk-related contingent features underlying these arrangements were triggered and (2) those counterparties with rights to do so requested collateral. As of September 30, 2026, the aggregate fair value of derivative instruments with credit risk-related contingent features in a gross liability position, the cash collateral posted, and the aggregate amount of additional collateral that counterparties could require were each immaterial to Ameren, Ameren Missouri, and Ameren Illinois.

NOTE 7 – FAIR VALUE MEASUREMENTS

Fair value is defined as the price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Fair value measurements are classified in three levels based on the fair value hierarchy as defined by GAAP. See Note 8 – Fair Value Measurements under Part II, Item 8, of the Form 10-K for information related to hierarchy levels and valuation techniques.

We consider nonperformance risk in our valuation of derivative instruments by analyzing our own credit standing and the credit standing of our counterparties, and by considering any credit enhancements (e.g., collateral). Included in our valuation, and based on current market conditions, is a valuation adjustment for counterparty default derived from market data such as the price of credit default swaps, bond yields, and credit ratings. No material gains or losses related to valuation adjustments for counterparty default risk were recorded at Ameren, Ameren Missouri, or Ameren Illinois in the three and nine months ended September 30, 2026 or 2025. At September 30, 2026, and December 31, 2025, the counterparty default risk valuation adjustment related to derivative contracts was immaterial for Ameren, Ameren Missouri, and Ameren Illinois.

26

---

Table of Contents

The following table sets forth, by level within the fair value hierarchy, our assets and liabilities measured at fair value on a recurring basis as of September 30, 2026, and December 31, 2025:

						September 30, 2026																		December 31, 2025
						Level 1			Level 2			Level 3			Total									Level 1			Level 2			Level 3			Total
Assets:
Ameren Missouri
			Derivative assets – commodity contracts:
			Fuel oils			$	21		$	—		$	—		$	21								$	—		$	—		$	—		$	—
			Natural gas			—			1			—			1									—			1			—			1
			Power			—			61			14			75									—			—			11			11
			Total derivative assets – commodity contracts			$	21		$	62		$	14		$	97								$	—		$	1		$	11		$	12
			Nuclear decommissioning trust fund:
			Equity securities:
			U.S. large capitalization			$	1,090		$	—		$	—		$	1,090								$	1,028		$	—		$	—		$	1,028
			Debt securities:
			U.S. Treasury and agency securities			—			233			—			233									—			225			—			225
			Corporate bonds			—			191			—			191									—			177			—			177
			Other			—			118			—			118									—			84			—			84
			Total nuclear decommissioning trust fund			$	1,090		$	542		$	—		$	1,632		(a)						$	1,028		$	486		$	—		$	1,514		(a)
			Total Ameren Missouri			$	1,111		$	604		$	14		$	1,729								$	1,028		$	487		$	11		$	1,526
Ameren Illinois
			Derivative assets – commodity contracts:
			Natural gas			$	—		$	2		$	3		$	5								$	—		$	2		$	2		$	4
			Power			—			—			5			5									—			—			—			—
			Total Ameren Illinois			$	—		$	2		$	8		$	10								$	—		$	2		$	2		$	4
Ameren
			Derivative assets – commodity contracts(b)			$	21		$	64		$	22		$	107								$	—		$	3		$	13		$	16
			Nuclear decommissioning trust fund(c)			1,090			542			—			1,632			(a)						1,028			486			—			1,514			(a)
			Total Ameren			$	1,111		$	606		$	22		$	1,739								$	1,028		$	489		$	13		$	1,530
Liabilities:
Ameren Missouri
			Derivative liabilities – commodity contracts:
			Fuel oils			$	—		$	—		$	—		$	—								$	5		$	—		$	—		$	5
			Natural gas			—			11			1			12									—			10			—			10
			Power			—			—			2			2									—			—			—			—
			Total Ameren Missouri			$	—		$	11		$	3		$	14								$	5		$	10		$	—		$	15
Ameren Illinois
			Derivative liabilities – commodity contracts:
			Natural gas			$	2		$	33		$	3		$	38								$	1		$	28		$	3		$	32
			Power			24			—			24			48									—			13			66			79
			Total Ameren Illinois			$	26		$	33		$	27		$	86								$	1		$	41		$	69		$	111
Ameren
			Derivative liabilities – commodity contracts(b)			$	26		$	44		$	30		$	100								$	6		$	51		$	69		$	126

(a)Balance excludes $6 million and $12 million of cash and cash equivalents, receivables, payables, and accrued income, net, for September 30, 2026, and December 31, 2025, respectively.

(b)See the Ameren Missouri and Ameren Illinois sections of the table for a breakout of the fair value of Ameren’s derivative assets and liabilities by type of commodity.

(c)See the Ameren Missouri section of the table for a breakout of the fair value of Ameren’s nuclear decommissioning trust fund by investment type.

27

---

Table of Contents

Level 3 natural gas derivative contract assets and liabilities measured at fair value on a recurring basis were immaterial for all periods presented. The following table presents the fair value reconciliation of Level 3 power derivative contract assets and liabilities measured at fair value on a recurring basis for the three and nine months ended September 30, 2026:

			2026
			Ameren Missouri			Ameren Illinois									Ameren
For the three months ended September 30:
Beginning balance at July 1			$	17		$	(39)								$	(22)
Realized and unrealized gains/(losses) included in regulatory assets/liabilities			—			19									19
Settlements			(5)			1									(4)
Ending balance at September 30			$	12		$	(19)								$	(7)
Change in unrealized gains/(losses) related to assets/liabilities held at September 30			$	—		$	18								$	18
For the nine months ended September 30:
Beginning balance at January 1			$	11		$	(66)								$	(55)
Realized and unrealized gains/(losses) included in regulatory assets/liabilities			14			28									42
Settlements			(13)			6									(7)
Transfers out of Level 3			—			13									13
Ending balance at September 30			$	12		$	(19)								$	(7)
Change in unrealized gains/(losses) related to assets/liabilities held at September 30			$	12		$	25								$	37

All gains or losses related to our Level 3 derivative commodity contracts are expected to be collected or refunded through customer rates; therefore, there is no impact to either net income or other comprehensive income resulting from changes in the fair value of these instruments.

The following table describes the valuation techniques and significant unobservable inputs utilized for the fair value of our Level 3 power derivative contract assets and liabilities as of September 30, 2026, and December 31, 2025:

									Fair Value																		Weighted Average(b)
			Commodity						Assets						Liabilities			Valuation Technique(s)			Unobservable Input(a)			Range
2026			Power(c)			$			19			$			(26)			Discounted cash flow			Average forward peak and off-peak pricing – forwards/swaps ($/MWh)			40 – 81			53
																					Nodal basis ($/MWh)			(12) – (3)			(6)
2025			Power(c)			$			11			$			(66)			Discounted cash flow			Average forward peak and off-peak pricing – forwards/swaps ($/MWh)			33 – 72			43
																					Nodal basis ($/MWh)			(9) – (2)			(5)

(a)Generally, significant increases (decreases) in these inputs in isolation would result in a significantly higher (lower) fair value measurement.

(b)Unobservable inputs were weighted by relative fair value.

(c)Valuations use visible forward prices adjusted for nodal-to-hub basis differentials.

The following table sets forth the carrying amount and, by level within the fair value hierarchy, the fair value of long-term debt (including current portion) disclosed, but not recorded, at fair value as of September 30, 2026, and December 31, 2025:

Long-Term Debt (Including Current Portion):			Carrying Amount(a)												Fair Value
															Level 2						Level 3						Total
			September 30, 2026
Ameren(b)			$	22,017											$	18,787					$	660		(c)			$	19,447
Ameren Missouri(d)			9,603												8,288						—						8,288
Ameren Illinois(d)			6,658												5,654						—						5,654
			December 31, 2025
Ameren(b)			$	19,187											$	17,433					$	559		(c)			$	17,992
Ameren Missouri(d)			8,230												7,608						—						7,608
Ameren Illinois(d)			6,259												5,753						—						5,753

(a)Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $159 million, $72 million, and $57 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of September 30, 2026. Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $136 million, $62 million, and $56 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of December 31, 2025.

(b)Amount excludes Ameren (parent)’s repurchase of Ameren Missouri’s senior secured notes and first mortgage bonds and Ameren Illinois’ first mortgage bonds that were accounted for as a debt extinguishment. See Note 4 – Long-term Debt and Equity Financings above and Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10-K for additional information.

(c)The Level 3 fair value amount consists of ATXI’s senior unsecured notes.

(d)Amount includes Ameren Missouri’s senior secured notes and first mortgage bonds and Ameren Illinois’ first mortgage bonds that were repurchased by Ameren (parent).

28

---

Table of Contents

The Ameren Companies’ carrying amounts of cash, cash equivalents, and restricted cash approximate fair value and are considered Level 1 in the fair value hierarchy. The Ameren Companies’ short-term borrowings approximate fair value because of the short-term nature of these instruments and are considered Level 2 in the fair value hierarchy.

NOTE 8 – RELATED-PARTY TRANSACTIONS

In the ordinary course of business, Ameren Missouri and Ameren Illinois have engaged in, and may in the future engage in, affiliate transactions. These transactions primarily consist of natural gas and power purchases and sales, services received or rendered, and borrowings and lendings. Transactions between Ameren’s subsidiaries are reported as affiliate transactions on their individual financial statements, but those transactions are eliminated in consolidation for Ameren’s consolidated financial statements. For a discussion of material related-party agreements and money pool agreements, see Note 13 – Related-party Transactions and Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of the Form 10-K.

Support Services Agreements

Ameren Missouri and Ameren Illinois had long-term receivables included in “Other assets” from Ameren Services of $32 million and $34 million, respectively, as of September 30, 2026, and $36 million and $38 million, respectively, as of December 31, 2025, related to Ameren Services’ allocated portion of Ameren’s pension and postretirement benefit plans.

Tax Allocation Agreement

See Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of the Form 10-K for a discussion of the tax allocation agreement. The following table presents the affiliate balances related to income taxes for Ameren Missouri and Ameren Illinois as of September 30, 2026, and December 31, 2025:

			September 30, 2026												December 31, 2025
			Ameren Missouri			Ameren Illinois									Ameren Missouri			Ameren Illinois
Income taxes payable to parent(a)			$	59		$	3								$	—		$	4
Income taxes receivable from parent(b)			—			6									3			7

(a)Included in “Accounts payable – affiliates” on the balance sheet.

(b)Included in “Accounts receivable – affiliates” on the balance sheet.

29

---

Table of Contents

Effects of Related-party Transactions on the Statement of Income

The following table presents the impact on Ameren Missouri and Ameren Illinois of related-party transactions for the three and nine months ended September 30, 2026 and 2025:

												Three Months												Nine Months
Agreement			Income Statement Line Item									Ameren Missouri						Ameren Illinois						Ameren Missouri						Ameren Illinois
Ameren Missouri and Ameren Illinois			Operating Revenues			2026			$			11			$			(a)			$			32			$			(a)
rent and facility services						2025						8						(a)						23						1
Ameren Illinois interconnection agreement			Operating Revenues			2026						(b)						1						(b)						1
with Ameren Missouri						2025						(b)						(a)						(b)						(a)
Ameren Missouri and Ameren Illinois miscellaneous			Operating Revenues			2026			$			(a)			$			2			$			2			$			3
support services						2025						1						(a)						1						5
Total Operating Revenues						2026			$			11			$			3			$			34			$			4
						2025						9						(a)						24						6
Ameren Missouri and Ameren Illinois			Purchased Power			2026			$			3			$			(a)			$			8			$			2
transmission services from ATXI						2025						2						1						7						2
Ameren Missouri interconnection agreement			Purchased Power			2026						1						(b)						1						(b)
with Ameren Illinois						2025						(a)						(b)						(a)						(b)
Total Purchased Power						2026			$			4			$			(a)			$			9			$			2
						2025						2						1						7						2
Ameren Missouri and Ameren Illinois			Other Operations and Maintenance			2026			$			2			$			2			$			2			$			2
rent and facility services						2025						(a)						(a)						(a)						3
Ameren Services support services			Other Operations and Maintenance			2026			$			46			$			43			$			142			$			133
agreement						2025						42						39						130						119
Total Other Operations and						2026			$			48			$			45			$			144			$			135
Maintenance						2025						42						39						130						122
Money pool interest (advances)			(Interest Charges)/Other Income, Net			2026			$			(a)			$			(a)			$			(a)			$			(a)
						2025						(a)						(a)						(a)						(a)
Long-term debt, net - related parties			(Interest Charges)			2026			$			(1)			$			(a)			$			(3)			$			(a)
						2025						(1)						(a)						(2)						(a)

(a)Amount less than $1 million.

(b)Not applicable.

NOTE 9 – COMMITMENTS AND CONTINGENCIES

We are involved in legal, tax, and regulatory proceedings before various courts, regulatory commissions, authorities, and governmental agencies with respect to matters that arise in the ordinary course of business, some of which involve substantial amounts of money. We believe that the final disposition of these proceedings, except as otherwise disclosed in the notes to our financial statements in this report and in the Form 10-K, will not have a material adverse effect on our results of operations, financial position, or liquidity.

Reference is made to Note 1 – Summary of Significant Accounting Policies, Note 2 – Rate and Regulatory Matters, Note 9 – Callaway Energy Center, Note 13 – Related-party Transactions, and Note 14 – Commitments and Contingencies under Part II, Item 8, of the Form 10-K. See also Note 1 – Summary of Significant Accounting Policies, Note 2 – Rate and Regulatory Matters, Note 8 – Related-party Transactions, and Note 10 – Callaway Energy Center of this report.

Environmental Matters

Our electric generation, transmission, and distribution and natural gas distribution and storage operations must comply with a variety of statutes and regulations relating to the protection of the environment and human health and safety, including permitting programs implemented by federal, state, and local authorities. Such environmental laws regulate air emissions; protect water bodies; regulate the handling and disposal of hazardous substances and waste materials; establish siting and land use requirements; and protect against ecological impacts. Complex and lengthy processes are required to obtain and renew approvals, permits, and licenses for new, existing, or modified energy-related facilities. Additionally, the use and handling of various chemicals and hazardous materials require release prevention plans and emergency response procedures.

Environmental regulations impact the electric utility industry, and compliance obligations could be costly for Ameren Missouri, which operates coal-fired and natural gas-fired energy centers. Compliance obligations under the Clean Air Act stem from a variety of programs

30

---

Table of Contents

including the NSPS, the MATS, emission allowance programs, the CSAPR, and the National Ambient Air Quality Standards, which are subject to periodic review for certain pollutants. Collectively, these regulations cover a variety of pollutants, such as SO2, particulate matter, NOx, mercury, toxic metals and acid gases, and CO2 emissions, although the scope of covered pollutants can change. To the extent our operations impact surface water bodies, including wetlands, the Clean Water Act requires permitting as well as evaluation of the ecological and biological impact of those operations. Implementation of requirements under the Clean Air Act and the Clean Water Act typically occurs through the issuance of permits by state regulators or resource agencies, and capital expenditures associated with compliance could be significant. The management and disposal of coal ash from our coal-fired energy centers must comply with federal regulations known as the CCR Rule issued under the Resource Conservation and Recovery Act and require the closure of surface impoundments at our coal-fired energy centers along with groundwater monitoring requirements and the implementation of corrective measures if necessary. The combined effects of compliance with existing and future environmental regulations and permitting could result in significant capital expenditures, increased operating costs, and the potential for closure or alteration of operations at some of Ameren Missouri’s energy centers. Ameren and Ameren Missouri expect that such compliance costs would be recoverable through rates, subject to MoPSC prudence review, but the timing of costs and their recovery could be subject to regulatory lag.

Additionally, Ameren Missouri’s wind generation facilities may be subject to operating restrictions to limit the impact on protected species. Since 2021, Ameren Missouri’s High Prairie Energy Center has curtailed nighttime operations from April through October to limit impacts on protected species during the critical biological season. Ameren Missouri does not anticipate these nighttime operating curtailments will have a material impact on its results of operations, financial position, or liquidity. In March 2026, Ameren Missouri submitted an application to the United States Fish and Wildlife Service for a new 30-year federal permit that allows for the continued operation of the High Prairie Energy Center. Ameren Missouri’s current permit expires in May 2027. Ameren and Ameren Missouri cannot predict when, or if, the permit application will be approved by the United States Fish and Wildlife Service.

Ameren and Ameren Missouri anticipate they may need to make estimated capital expenditures of $50 million to $80 million from 2026 through 2031 to comply with environmental regulations. Additional capital expenditures beyond 2031 could be required. This estimate includes surface impoundment closure and corrective action measures required by the 2015 and 2024 CCR rules and modifications to cooling water intake structures at existing power plants under Clean Water Act rules, all of which are discussed below. The EPA could review and revise compliance requirements. In addition to planned retirements of coal-fired energy centers that were included in Ameren Missouri’s 2026 PRP and with respect to the Illinois emissions standards discussed in Note 14 – Commitments and Contingencies under Part II, Item 8, of the Form 10-K, Ameren Missouri’s current plan for compliance with existing air emission regulations includes burning low-sulfur coal and optimizing existing air pollution control equipment. Accordingly, the actual amount of capital expenditures required to comply with existing environmental regulations could vary from the above estimates because of uncertainty as to revisions to regulatory requirements by the EPA and/or state regulators and their timing and varying cost of potential compliance strategies, among other things.

The following sections describe the significant environmental statutes and regulations and environmental enforcement and remediation matters that affect or could affect our operations. The EPA could revise all or part of such federal regulations.

Clean Air Act

Federal and state laws, including the CSAPR, regulate emissions of SO2 and NOx through the reduction of emissions at their source and the use and retirement of emission allowances available for state budgets. In 2022, the EPA proposed the Good Neighbor Rule to reduce the transport of ozone from power plants by reducing the amount of CSAPR NOx allowances available for compliance. In January 2026, the EPA issued a proposed rule to reconsider the Good Neighbor Rule which, if finalized as proposed, would resolve underlying litigation involving numerous states including Missouri. Ameren Missouri complies with the current CSAPR requirements by minimizing emissions with low-sulfur coal, operation of two scrubbers at its Sioux Energy Center, and optimization of existing NOx air pollution control equipment. If a final rule is issued similar to the proposed rule, Ameren Missouri would not expect additional NOx controls at its coal-fired energy centers to be necessary.

CO2 Emissions Standards

In 2024, the EPA issued a final rule that set CO2 emission standards for existing coal-fired and new natural gas-fired power plants based on the emissions expected from adoption of carbon capture technology and/or natural gas co-firing for coal-fired power plants and carbon capture technology for new natural gas-fired power plants. In September 2026, the EPA issued a final rule partially repealing the 2024 rule, including provisions related to existing power plants and certain carbon capture standards on new natural gas-fired power plants. Also in September 2026, the EPA issued a proposed rule to repeal all remaining greenhouse gas emissions standards for fossil fuel-fired power plants, including the remaining provisions under the 2024 rule. Previously, in February 2026, the EPA issued a final rule to rescind its 2009 Greenhouse Gas Endangerment Finding, which was the basis for implementing greenhouse gas emissions standards. Litigation regarding the rescission of the Endangerment Finding is ongoing and litigation regarding the EPA’s partial repeal of the 2024 final rule is expected. Ameren and Ameren Missouri are assessing the final rules and, at this time, cannot predict the impacts of the final rules on their results of operations, financial position, and liquidity.

31

---

Table of Contents

MATS

In February 2026, the EPA issued a final rule repealing a 2024 rule that had revised the MATS and established more stringent standards for emissions of particulate matter and mercury and required the use of continuous emissions monitoring systems. As a result of the repeal, the 2024 rule will not impact Ameren’s and Ameren Missouri’s results of operations, financial position, and liquidity.

NSPS

In January 2026, the EPA issued a final rule that established NOx emission standards for several subcategories of stationary CTs that began construction after mid-December 2024, based on size, utilization, design efficiency, and fuel type. Ameren and Ameren Missouri do not expect the final rule to materially impact their results of operations, financial position, and liquidity.

Clean Water Act

All of Ameren Missouri’s coal-fired and nuclear energy centers are subject to Clean Water Act requirements to identify measures for reducing the number of aquatic organisms impinged on a power plant’s cooling water intake screens or entrained through the plant’s cooling water system. Cooling water intake requirements are implemented by state regulators through the permit renewal process of each power plant’s water discharge permit. Permits for Ameren Missouri’s coal-fired and nuclear energy centers are in the process of renewal.

CCR Management

The EPA’s 2015 CCR Rule establishes requirements for the management and disposal of CCR from coal-fired power plants and has resulted in the closure of surface impoundments at Ameren Missouri’s energy centers, with closures of two surface impoundments in process at its retired Meramec Energy Center as a part of the construction of the Castle Bluff Natural Gas Project. Ameren Missouri’s CCR management compliance plan includes installation of groundwater monitoring equipment and groundwater treatment facilities. In 2024, the EPA revised the CCR Rule to include certain active and inactive CCR surface impoundments and disposal units not previously included in the 2015 CCR Rule. Ameren and Ameren Missouri recorded AROs of $57 million associated with CCR storage facilities on their respective balance sheets as of September 30, 2026. This amount includes an immaterial incremental ARO related to the 2024 CCR Rule, which may be revised as additional site studies are performed or as new information becomes available. In April 2026, the EPA issued a proposed rule that reconsiders aspects of the 2015 and 2024 CCR rules and proposes various amendments and compliance alternatives. Ameren and Ameren Missouri are monitoring the ongoing regulatory developments but, at this time, cannot predict the final impacts of the CCR rules or the EPA’s proposed revisions on their results of operations, financial position, and liquidity.

Remediation

The Ameren Companies are involved in a number of remediation actions to clean up sites impacted by the use or disposal of materials containing hazardous substances. Federal and state laws can require responsible parties to fund remediation regardless of their degree of fault, the legality of original disposal, or the ownership of a disposal site.

As of September 30, 2026, Ameren Illinois has remediated the majority of the 44 former MGP sites that it is responsible for in Illinois with an estimated remaining obligation primarily related to three of these former MGP sites at $45 million to $90 million. Ameren and Ameren Illinois recorded a liability of $45 million to represent the estimated minimum obligation for these sites, as no other amount within the range was a better estimate. Ameren and Ameren Illinois cannot estimate the completion dates of the estimated remaining obligation or the scope of any future remediation due to site accessibility, among other things. Considerable uncertainty remains in these estimates because many site-specific factors can influence the actual costs, including unanticipated underground structures, the degree to which groundwater is impacted, regulatory changes, local ordinances, and site accessibility. The actual costs and timing of completion may vary substantially from these estimates.

The ICC allows Ameren Illinois to recover MGP remediation and related litigation costs from its electric and natural gas utility customers through environmental cost riders that are subject to annual prudence reviews by the ICC.

Our operations or those of our predecessor companies involve the use of, disposal of, and, in appropriate circumstances, the cleanup of substances regulated under environmental laws. Such historical practices may result in future environmental commitments, including additional or more stringent cleanup standards. We are unable to determine whether such historical practices will affect our results of operations, financial position, or liquidity.

32

---

Table of Contents

NOTE 10 – CALLAWAY ENERGY CENTER

See Note 9 – Callaway Energy Center under Part II, Item 8, of the Form 10-K for information regarding spent nuclear fuel recovery, recovery of decommissioning costs, and the nuclear decommissioning trust fund. The fair value of the trust fund for Ameren Missouri’s Callaway Energy Center is reported as “Nuclear decommissioning trust fund” in Ameren’s and Ameren Missouri’s balance sheets. This amount is legally restricted and may be used only to fund the costs of nuclear decommissioning. Changes in the fair value of the trust fund are recorded as an increase or decrease to the nuclear decommissioning trust fund, with an offsetting adjustment to the related regulatory liability. Ameren and Ameren Missouri have recorded an ARO for the Callaway Energy Center decommissioning costs at fair value, which represents the present value of estimated future cash outflows. Every three years, the MoPSC requires Ameren Missouri to file an updated cost study and funding analysis for decommissioning its Callaway Energy Center. An updated cost study and funding analysis was filed with the MoPSC in September 2026 and resulted in an immaterial change in the ARO balance as of September 30, 2026. The updated cost study proposed to maintain the annual customer contributions for funding the Callaway Energy Center decommissioning costs at zero consistent with a May 2025 MoPSC order, as the trust fund level exceeded the estimated present value of future decommissioning costs. See Note 13 – Supplemental Information for more information on Ameren Missouri’s AROs.

Insurance

The following table presents insurance coverage at Ameren Missouri’s Callaway Energy Center at September 30, 2026:

Type and Source of Coverage			Most Recent Renewal Date			Maximum Coverages						Maximum Assessments for Single Incidents
Public liability and nuclear worker liability:
American Nuclear Insurers			January 1, 2026			$	500					$	—
Pool participation			(a)			15,929			(a)			166			(b)
						$	16,429		(c)			$	166
Property damage:
NEIL and EMANI			April 1, 2026			$	3,200		(d)			$	23		(e)
Accidental outage:
NEIL			April 1, 2026			$	490		(f)			$	9		(e)

(a)Provided through mandatory participation in an industrywide retrospective premium assessment program. The maximum coverage available is dependent on the number of United States commercial reactors participating in the program.

(b)Retrospective premium under the Price-Anderson Act. This is subject to retrospective assessment with respect to a covered loss in excess of $500 million in the event of an incident at any licensed United States commercial reactor, payable at $25 million per year.

(c)Limit of liability for each incident under the Price-Anderson liability provisions of the Atomic Energy Act of 1954, as amended. This limit is subject to change to account for the effects of inflation and changes in the number of licensed power reactors.

(d)NEIL provides $2.7 billion in property damage, stabilization, decontamination, and premature decommissioning insurance for radiation events and $0.7 billion in property damage insurance for nonradiation events. EMANI provides $490 million in property damage insurance for both radiation and nonradiation events.

(e)All NEIL-insured plants could be subject to retrospective assessments should losses exceed the accumulated funds from NEIL.

(f)Accidental outage insurance provides for lost sales in the event of a prolonged accidental outage. Weekly indemnity up to $4.5 million for 52 weeks, which commences after the first 12 weeks of an outage, plus up to $3.6 million per week for a minimum of 71 weeks thereafter for a total not exceeding the policy limit of $490 million. Nonradiation events are limited to $291 million.

The Price-Anderson Act is a federal law that limits the liability for claims from an incident involving any licensed United States commercial nuclear energy center. The limit is based on the number of licensed reactors. The limit of liability and the maximum potential annual payments are adjusted at least every five years for inflation to reflect changes in the Consumer Price Index. The most recent five-year inflationary adjustment became effective in October 2023. Owners of a nuclear reactor cover this exposure through a combination of private insurance and mandatory participation in a financial protection pool, as established by the Price-Anderson Act.

Losses resulting from terrorist attacks on nuclear facilities insured by NEIL are subject to industrywide aggregates, such that terrorist acts against one or more commercial nuclear power plants within a stated time period would be treated as a single event, and the owners of the nuclear power plants would share the limit of liability. NEIL policies have an aggregate limit of $3.2 billion within a 12-month period for radiation events, or $1.8 billion for events not involving radiation contamination, resulting from terrorist attacks. The EMANI policies are not subject to industrywide aggregates in the event of terrorist attacks on nuclear facilities.

If losses from a nuclear incident at the Callaway Energy Center exceed insurance limits, or are not covered by insurance, or if coverage is unavailable, Ameren Missouri is at risk for any uninsured losses. If a serious nuclear incident were to occur, it could have a material adverse effect on Ameren’s and Ameren Missouri’s results of operations, financial position, or liquidity.

33

---

Table of Contents

NOTE 11 – RETIREMENT BENEFITS

The following table presents the components of the net periodic benefit cost (income) incurred for Ameren’s pension and postretirement benefit plans for the three and nine months ended September 30, 2026 and 2025:

			Pension Benefits																											Postretirement Benefits
			Three Months												Nine Months															Three Months												Nine Months
			2026						2025						2026						2025									2026						2025						2026						2025
Service cost(a)			$	22					$	21					$	62					$	62								$	2					$	3					$	7					$	8
Non-service cost components:
Interest cost			56						58						169						175									10						11						33						33
Expected return on plan assets(b)			(63)						(76)						(197)						(227)									(24)						(24)						(71)						(71)
Amortization of:(b)
Prior service cost (credit)			—						—						—						—									(1)						(1)						(3)						(3)
Actuarial (gain) loss			3						(9)						8						(26)									(7)						(9)						(23)						(27)
Total non-service cost components(c)			$	(4)					$	(27)					$	(20)					$	(78)								$	(22)					$	(23)					$	(64)					$	(68)
Net periodic benefit cost (income)(d)			$	18					$	(6)					$	42					$	(16)								$	(20)					$	(20)					$	(57)					$	(60)

(a)Service cost, net of capitalization, is reflected in “Operating Expenses – Other operations and maintenance” on Ameren’s statement of income.

(b)Prior service cost (credit) is amortized on a straight-line basis over the average future service of active participants benefiting under a plan amendment. Net actuarial gains or losses subject to amortization are amortized over 10 years. Expected return on plan assets is based on a market-related value of assets that recognizes asset (gains) losses over 4 years.

(c)Non-service cost components are reflected in “Other Income, Net” on Ameren’s consolidated statement of income. See Note 5 – Other Income, Net for additional information.

(d)Does not include the impact of the tracker for the difference between the level of pension and postretirement benefit costs (income) incurred by Ameren Missouri under GAAP and the level of such costs included in customer rates.

Ameren Missouri and Ameren Illinois are responsible for their respective share of Ameren’s pension and other postretirement costs. The following table presents the respective share of net periodic pension and other postretirement benefit costs (income) incurred for the three and nine months ended September 30, 2026 and 2025:

			Pension Benefits																											Postretirement Benefits
			Three Months												Nine Months															Three Months												Nine Months
			2026						2025						2026						2025									2026						2025						2026						2025
Ameren Missouri(a)			$	7					$	(4)					$	18					$	(11)								$	(6)					$	(7)					$	(17)					$	(21)
Ameren Illinois			10						(1)						22						(3)									(14)						(13)						(40)						(39)
Other			1						(1)						2						(2)									(b)						(b)						(b)						(b)
Ameren(a)			$	18					$	(6)					$	42					$	(16)								$	(20)					$	(20)					$	(57)					$	(60)

(a)Does not include the impact of the tracker for the difference between the level of pension and postretirement benefit costs (income) incurred by Ameren Missouri under GAAP and the level of such costs included in customer rates.

(b)Amount less than $1 million.

34

---

Table of Contents

NOTE 12 – INCOME TAXES

The following table presents the principal reasons for the difference between the effective income tax expense and rate and the federal statutory corporate income tax expense and rate for the three and nine months ended September 30, 2026 and 2025:

			Three Months									Three Months									Nine Months									Nine Months
			2026									2025									2026									2025
			Amount						Effective Tax Rate			Amount						Effective Tax Rate			Amount						Effective Tax Rate			Amount						Effective Tax Rate
Ameren
Federal statutory corporate income tax expense and rate			$	167					21		%	$	145					21		%	$	332					21		%	$	284					21		%
State and local taxes, net of federal income tax(a)			45						5			33						5			86						5			73						5
Tax credits
Renewable energy tax credits(b)			(34)						(4)			(22)						(3)			(67)						(4)			(50)						(3)
Other			(3)						(1)			(2)						(1)			(6)						(1)			(7)						(1)
Nontaxable or nondeductible items			—						—			1						—			(4)						—			(1)						—
Other adjustments
Amortization of excess deferred income taxes(c)			(46)						(5)			(45)						(7)			(88)						(6)			(92)						(7)
Revaluation of excess deferred income taxes(d)			—						—			(48)						(7)			—						—			(48)						(3)
Depreciation differences			(10)						(1)			(10)						(1)			(22)						(1)			(14)						(1)
Effective income tax expense and rate			$	119					15		%	$	52					7		%	$	231					14		%	$	145					11		%
Ameren Missouri
Federal statutory corporate income tax expense and rate			$	125					21		%	$	116					21		%	$	175					21		%	$	159					21		%
State and local taxes, net of federal income tax(a)			17						3			16						3			23						3			22						3
Tax credits
Renewable energy tax credits(b)			(55)						(9)			(42)						(7)			(76)						(8)			(55)						(7)
Other			(3)						(1)			(2)						(1)			(5)						(2)			(6)						(1)
Other adjustments
Amortization of excess deferred income taxes(c)			(63)						(10)			(51)						(9)			(87)						(10)			(70)						(9)
Depreciation differences			(10)						(2)			(5)						(1)			(15)						(2)			(7)						(1)
Effective income tax expense (benefit) and rate			$	11					2		%	$	32					6		%	$	15					2		%	$	43					6		%
Ameren Illinois
Federal statutory corporate income tax expense and rate			$	42					21		%	$	35					21		%	$	157					21		%	$	138					21		%
State and local taxes, net of federal income tax(a)			15						8			12						7			57						7			48						7
Nontaxable or nondeductible items			—						—			2						1			(1)						—			2						—
Other adjustments
Amortization of excess deferred income taxes(c)			(4)						(2)			(6)						(4)			(11)						(1)			(24)						(4)
Revaluation of excess deferred income taxes(d)			—						—			(23)						(14)			—						—			(23)						(4)
Depreciation differences			—						—			(3)						(1)			(5)						(1)			(7)						—
Effective income tax expense and rate			$	53					27		%	$	17					10		%	$	197					26		%	$	134					20		%

(a)State taxes in Missouri and Illinois made up the majority of the tax effect in this category for Ameren, Ameren Missouri, and Ameren Illinois.

(b)The benefit of the credits associated with Missouri renewable energy standard compliance is refunded to customers through the RESRAM. The benefit of the credits associated with the production and investment tax credit tracker will be refunded to customers based on MoPSC approval in a regulatory rate review.

(c)Reflects the amortization of a regulatory liability resulting from the revaluation of accumulated deferred income taxes subject to regulatory ratemaking, which are being refunded to customers.

(d)In 2024, the IRS issued a series of private letter rulings to another taxpayer, which provided guidance on applying IRS normalization rules to the calculation of tax benefits applicable to the ratemaking treatment related to net operating loss carryforwards. The rulings concluded that, for ratemaking purposes, net operating loss carryforwards should be reflected on a separate company basis and should not be reduced by payments received for the utilization of losses by other affiliates under a tax allocation agreement. In 2025, the FERC issued an order reflecting implementation of the rules for the other taxpayer who had a similar fact pattern as Ameren Illinois and ATXI. Accordingly, in the third quarter of 2025, Ameren and Ameren Illinois decreased income tax expense by $48 million and $23 million, respectively, to reflect the revaluation of excess deferred income tax regulatory liabilities resulting from TCJA for FERC-regulated jurisdictions pursuant to IRS guidance and a 2025 FERC order.

35

---

Table of Contents

NOTE 13 – SUPPLEMENTAL INFORMATION

Cash, Cash Equivalents, and Restricted Cash

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets and the statements of cash flows at September 30, 2026, and December 31, 2025:

			September 30, 2026																					December 31, 2025
			Ameren						Ameren Missouri						Ameren Illinois									Ameren						Ameren Missouri						Ameren Illinois
“Cash and cash equivalents”			$	40					$	26					$	11								$	13					$	6					$	3
Restricted cash included in “Other current assets”			56						45						6									63						54						5
Restricted cash included in “Other assets”			426						—						426									336						—						336
Restricted cash included in “Nuclear decommissioning trust fund”			3						3						—									8						8						—
Total cash, cash equivalents, and restricted cash			$	525					$	74					$	443								$	420					$	68					$	344

Restricted cash included in “Other current assets” represents funds held by an irrevocable Voluntary Employee Beneficiary Association (VEBA) trust, which provides health care benefits for active employees on Ameren’s, Ameren Missouri’s, and Ameren Illinois’ balance sheets, funds held in an escrow account for programs established as a result of a 2024 court order resolving outstanding claims in the NSR and Clean Air Act litigation on Ameren’s and Ameren Missouri’s balance sheets, and AMF’s restricted cash for payments for securitized utility tariff bonds on Ameren’s and Ameren Missouri’s balance sheets. Restricted cash included in “Other assets” on Ameren’s and Ameren Illinois’ balance sheets primarily represents amounts collected under a cost recovery rider restricted for use in the procurement of renewable energy credits and amounts in a trust fund restricted for the use of funding certain asbestos-related claims.

Accounts Receivable

“Accounts receivable – trade” on Ameren’s and Ameren Illinois’ balance sheets include certain receivables purchased at a discount from alternative retail electric suppliers that elect to participate in the utility consolidated billing program. At September 30, 2026, and December 31, 2025, Ameren’s and Ameren Illinois’ balance sheets included payables for purchased receivables of $65 million and $47 million, respectively. On Ameren’s balance sheet, these amounts were included in “Other current liabilities”.

The following table provides a reconciliation of the beginning and ending amount of the allowance for doubtful accounts for the three and nine months ended September 30, 2026 and 2025:

			Three Months															Nine Months
			2026						2025									2026						2025
Ameren:
Beginning of period			$	45					$	39								$	39					$	30
Bad debt expense			21						18									42						37
Charged to other accounts(a)			3						2									6						5
Net write-offs			(22)						(21)									(40)						(34)
End of period			$	47					$	38								$	47					$	38
Ameren Missouri:
Beginning of period			$	17					$	12								$	17					$	12
Bad debt expense			7						7									13						11
Net write-offs			(5)						(4)									(11)						(8)
End of period			$	19					$	15								$	19					$	15
Ameren Illinois:(b)
Beginning of period			$	28					$	27								$	22					$	18
Bad debt expense			14						11									29						26
Charged to other accounts(a)			3						2									6						5
Net write-offs			(17)						(17)									(29)						(26)
End of period			$	28					$	23								$	28					$	23

(a)Amounts associated with the allowance for doubtful accounts related to receivables purchased by Ameren Illinois from alternative retail electric suppliers, as required by the Illinois Public Utilities Act.

(b)Ameren Illinois has rate-adjustment mechanisms that allow it to recover the difference between its actual net bad debt write-offs under GAAP, including those associated with receivables purchased from alternative retail electric suppliers, and the amount of net bad debt write-offs included in its base rates. The table above does not include the impact related to the riders.

36

---

Table of Contents

Supplemental Cash Flow Information

The following table provides noncash financing and investing activity excluded from the statements of cash flows for the nine months ended September 30, 2026 and 2025:

			September 30, 2026																		September 30, 2025
			Ameren						Ameren Missouri						Ameren Illinois						Ameren			Ameren Missouri			Ameren Illinois
Investing:
Accrued capital expenditures, including nuclear fuel expenditures			$	503					$	312					$	148					$	412		$	277		$	147
Net realized and unrealized gain – nuclear decommissioning trust fund			91						91						—						136			136			—
Financing:
Issuance of common stock for stock-based compensation			$	25					$	—					$	—					$	25		$	—		$	—
Issuance of common stock under the DRPlus			6						—						—						7			—			—

Asset Retirement Obligations

The following table provides a reconciliation of the beginning and ending carrying amount of AROs for the nine months ended September 30, 2026:

			Ameren Missouri						Ameren Illinois												Ameren
Balance at December 31, 2025			$	849		(a)			$	5								(b)			$	854		(a)
Liabilities incurred			7						—												7
Liabilities settled			(3)						(c)												(3)
Accretion			28			(d)			(c)												28			(d)
Change in estimates			(20)						—												(20)
Balance at September 30, 2026			$	861		(a)			$	5								(b)			$	866		(a)

(a)Balance included $3 million and $5 million in “Other current liabilities” on the balance sheet as of September 30, 2026, and December 31, 2025, respectively.

(b)Included in “Other deferred credits and liabilities” on the balance sheet.

(c)Amount less than $1 million.

(d)Accretion expense attributable to Ameren Missouri was recorded as a decrease to regulatory liabilities.

Deferred Compensation

At September 30, 2026, and December 31, 2025, the present value of benefits to be paid for deferred compensation obligations was $80 million and $79 million, respectively, which was primarily reflected in “Other deferred credits and liabilities” on Ameren’s consolidated balance sheet.

Operating Revenues

As of September 30, 2026 and 2025, our remaining performance obligations for contracts with a term greater than one year were immaterial. The Ameren Companies elected not to disclose the aggregate amount of the transaction price allocated to the performance obligations that are unsatisfied as of the end of the reporting period for contracts with an initial expected term of one year or less. See Note 14 – Segment Information for disaggregated revenue information.

Excise Taxes

Ameren Missouri and Ameren Illinois collect from their customers excise taxes, including municipal and state excise taxes and gross receipts taxes that are levied on the sale or distribution of natural gas and electricity. The following table presents the excise taxes recorded on a gross basis in “Operating Revenues – Electric,” “Operating Revenues – Natural gas,” and “Operating Expenses – Taxes other than income taxes” on the statements of income for the three and nine months ended September 30, 2026 and 2025:

			Three Months												Nine Months
			2026						2025						2026						2025
Ameren Missouri			$	75					$	69					$	162					$	150
Ameren Illinois			34						30						111						104
Ameren			$	109					$	99					$	273					$	254

37

---

Table of Contents

Earnings per Share

The following table reconciles the basic weighted-average number of common shares outstanding to the diluted weighted-average number of common shares outstanding for the three and nine months ended September 30, 2026 and 2025:

			Three Months												Nine Months
			2026						2025						2026						2025
Weighted-average Common Shares Outstanding – Basic			276.8						270.4						276.7						270.2
Assumed settlement of performance share units and restricted stock units			1.1						0.8						1.0						0.9
Dilutive effect of forward sale agreements			1.0						1.0						1.0						0.6
Weighted-average Common Shares Outstanding – Diluted(a)			278.9						272.2						278.7						271.7

(a)There was an immaterial number of anti-dilutive performance share units excluded from the earnings per diluted share calculations for the three and nine months ended September 30, 2026 and 2025. Outstanding forward sale agreements as of September 30, 2026 and 2025 that were anti-dilutive for the three and nine months ended September 30, 2026 and 2025 were excluded from earnings per diluted share as calculated using the treasury stock method, including 6.0 million and 12.3 million shares for the three and nine months ended September 30, 2026 and an immaterial number of shares for the three and nine months ended September 30, 2025. For additional information about the outstanding forward sale agreements, see Note 4 – Long-term Debt and Equity Financings.

NOTE 14 – SEGMENT INFORMATION

The following tables present revenues, specified items reflected in net income attributable to common shareholders, and capital expenditures by segment at Ameren and Ameren Illinois for the three and nine months ended September 30, 2026 and 2025. Ameren, Ameren Missouri, and Ameren Illinois management review segment capital expenditure information rather than any individual or total asset amount. For additional information about our segments, see Note 16 – Segment Information under Part II, Item 8, of the Form 10-K.

Ameren

			Reportable Segments
			Ameren Missouri						Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Transmission						Other						Intersegment Eliminations						Ameren
Three Months 2026:
External revenues			$	1,770					$	774					$	136					$	202					$	—					$	—					$	2,882
Intersegment revenues			11						3						—						64						—						(78)						—
Revenue			1,781						777						136						266						—						(78)						2,882
Fuel and purchased power(a)			(509)						(360)						—						—						—						60						(809)
Natural gas purchased for resale(a)			(5)						—						(23)						—						—						—						(28)
Other operations and maintenance expenses(a)			(274)						(182)						(58)						(34)						(5)						18						(535)
Other segment items
Depreciation and amortization			(246)						(100)						(34)						(55)						(1)						—						(436)
Taxes other than income taxes			(129)						(23)						(17)						(2)						(3)						—						(174)
Other income (expense), net			58						17						3						6						30						(2)						112
Interest charges			(82)						(30)						(18)						(32)						(56)						2						(216)
Income (taxes) benefit			(11)						(27)						4						(39)						(46)						—						(119)
Noncontrolling interests – preferred stock dividends			(1)						—						—						—						—						—						(1)
Net income (loss) attributable to Ameren common shareholders			$	582					$	72					$	(7)					$	110					$	(81)					$	—					$	676
Interest income			$	3					$	5					$	—					$	—					$	2					$	(2)					$	8
Capital expenditures			979						223						81						153						—						—						1,436

38

---

Table of Contents

			Reportable Segments
			Ameren Missouri						Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Transmission						Other						Intersegment Eliminations						Ameren
Three Months 2025:
External revenues			$	1,696					$	698					$	117					$	188					$	—					$	—					$	2,699
Intersegment revenues			9						1						—						52						—						(62)						—
Revenue			1,705						699						117						240						—						(62)						2,699
Fuel and purchased power(a)			(487)						(330)						—						—						—						49						(768)
Natural gas purchased for resale(a)			(6)						—						(19)						—						—						—						(25)
Other operations and maintenance expenses(a)			(260)						(171)						(55)						(19)						(10)						13						(502)
Other segment items
Depreciation and amortization			(239)						(92)						(33)						(49)						(2)						—						(415)
Taxes other than income taxes			(122)						(22)						(15)						(3)						(2)						—						(164)
Other income (expense), net			45						20						4						(3)						11						(1)						76
Interest charges			(85)						(28)						(16)						(31)						(49)						1						(208)
Income (taxes) benefit			(32)						(19)						4						16						(21)						—						(52)
Noncontrolling interests – preferred stock dividends			(1)						—						—						—						—						—						(1)
Net income (loss) attributable to Ameren common shareholders			$	518					$	57					$	(13)					$	151		(b)			$	(73)					$	—					$	640
Interest income			$	3					$	6					$	—					$	1					$	1					$	(1)					$	10
Capital expenditures			548						163						78						174						1						24						988
Nine Months 2026:
External revenues			$	3,801					$	2,046					$	748					$	555					$	—					$	—					$	7,150
Intersegment revenues			34						3						—						167						—						(204)						—
Revenue			3,835						2,049						748						722						—						(204)						7,150
Fuel and purchased power(a)			(1,041)						(864)						—						—						—						156						(1,749)
Natural gas purchased for resale(a)			(46)						—						(192)						—						—						—						(238)
Other operations and maintenance expenses(a)			(820)						(507)						(182)						(74)						(12)						48						(1,547)
Other segment items
Depreciation and amortization			(694)						(294)						(101)						(160)						(5)						—						(1,254)
Taxes other than income taxes			(325)						(66)						(63)						(7)						(10)						—						(471)
Other income (expense), net			171						54						10						19						72						(6)						320
Interest charges			(247)						(86)						(51)						(94)						(157)						6						(629)
Income (taxes) benefit			(15)						(77)						(45)						(102)						8						—						(231)
Noncontrolling interests – preferred stock dividends			(3)						(1)						—						—						—						—						(4)
Net income (loss) attributable to Ameren common shareholders			$	815					$	208					$	124					$	304					$	(104)					$	—					$	1,347
Interest income			$	8					$	16					$	—					$	—					$	6					$	(6)					$	24
Capital expenditures			2,750						599						211						523						3						3						4,089

39

---

Table of Contents

			Reportable Segments
			Ameren Missouri						Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Transmission						Other						Intersegment Eliminations						Ameren
Nine Months 2025:
External revenues			$	3,978					$	1,838					$	686					$	515					$	—					$	—					$	7,017
Intersegment revenues			24						6						—						143						—						(173)						—
Revenue			4,002						1,844						686						658						—						(173)						7,017
Fuel and purchased power(a)			(1,431)						(765)						—						—						—						132						(2,064)
Natural gas purchased for resale(a)			(45)						—						(188)						—						—						—						(233)
Other operations and maintenance expenses(a)			(748)						(493)						(165)						(56)						(26)						41						(1,447)
Other segment items
Depreciation and amortization			(642)						(276)						(98)						(146)						(6)						—						(1,168)
Taxes other than income taxes			(300)						(63)						(60)						(7)						(9)						—						(439)
Other income (expense), net			135						66						14						14						31						(3)						257
Interest charges			(215)						(80)						(47)						(89)						(142)						3						(570)
Income (taxes) benefit			(43)						(48)						(37)						(48)						31						—						(145)
Noncontrolling interests – preferred stock dividends			(3)						(1)						—						—						—						—						(4)
Net income (loss) attributable to Ameren common shareholders			$	710					$	184					$	105					$	326		(b)			$	(121)					$	—					$	1,204
Interest income			$	7					$	22					$	—					$	2					$	3					$	(3)					$	31
Capital expenditures			1,873						483						225						505						6						26						3,118

(a)Significant segment expense that is regularly provided to the CODMs. Intersegment expenses are included within the amounts shown.

(b)Ameren Transmission earnings reflect an allocation of financing costs from Ameren (parent).

40

---

Table of Contents

Ameren Illinois

			Reportable Segments
			Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Illinois Transmission						Intersegment Eliminations						Ameren Illinois
Three Months 2026:
External revenues			$	777					$	136					$	140					$	—					$	1,053
Intersegment revenues			—						—						56						(56)						—
Revenue			777						136						196						(56)						1,053
Purchased power(a)			(360)						—						—						56						(304)
Natural gas purchased for resale(a)			—						(23)						—						—						(23)
Other operations and maintenance expenses(a)			(182)						(58)						(25)						—						(265)
Other segment items
Depreciation and amortization			(100)						(34)						(41)						—						(175)
Taxes other than income taxes			(23)						(17)						(2)						—						(42)
Other income, net			17						3						5						—						25
Interest charges			(30)						(18)						(24)						—						(72)
Income (taxes) benefit			(27)						4						(30)						—						(53)
Net income (loss) available to common shareholder			72						(7)						79						—						144
Interest income			5						—						—						—						5
Capital expenditures			223						81						78						—						382
Three Months 2025:
External revenues			$	699					$	117					$	130					$	—					$	946
Intersegment revenues			—						—						46						(46)						—
Revenue			699						117						176						(46)						946
Purchased power(a)			(330)						—						—						46						(284)
Natural gas purchased for resale(a)			—						(19)						—						—						(19)
Other operations and maintenance expenses(a)			(171)						(55)						(15)						—						(241)
Other segment items
Depreciation and amortization			(92)						(33)						(37)						—						(162)
Taxes other than income taxes			(22)						(15)						(1)						—						(38)
Other income, net			20						4						6						—						30
Interest charges			(28)						(16)						(23)						—						(67)
Income (taxes) benefit			(19)						4						(2)						—						(17)
Net income (loss) available to common shareholder			57						(13)						104						—						148
Interest income			6						—						1						—						7
Capital expenditures			163						78						144						—						385

41

---

Table of Contents

			Reportable Segments
			Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Illinois Transmission						Intersegment Eliminations						Ameren Illinois
Nine Months 2026:
External revenues			$	2,049					$	748					$	383					$	—					$	3,180
Intersegment revenues			—						—						145						(145)						—
Revenue			2,049						748						528						(145)						3,180
Purchased power(a)			(864)						—						—						145						(719)
Natural gas purchased for resale(a)			—						(192)						—						—						(192)
Other operations and maintenance expenses(a)			(507)						(182)						(56)						—						(745)
Other segment items
Depreciation and amortization			(294)						(101)						(122)						—						(517)
Taxes other than income taxes			(66)						(63)						(4)						—						(133)
Other income, net			54						10						16						—						80
Interest charges			(86)						(51)						(72)						—						(209)
Income taxes			(77)						(45)						(75)						—						(197)
Noncontrolling interests – preferred stock dividends			(1)						—						—						—						(1)
Net income available to common shareholder			$	208					$	124					$	215					$	—					$	547
Interest income			$	16					$	—					$	—					$	—					$	16
Capital expenditures			599						211						278						—						1,088
Nine Months 2025:
External revenues			$	1,844					$	686					$	359					$	—					$	2,889
Intersegment revenues			—						—						123						(123)						—
Revenue			1,844						686						482						(123)						2,889
Purchased power(a)			(765)						—						—						123						(642)
Natural gas purchased for resale(a)			—						(188)						—						—						(188)
Other operations and maintenance expenses(a)			(493)						(165)						(44)						—						(702)
Other segment items
Depreciation and amortization			(276)						(98)						(110)						—						(484)
Taxes other than income taxes			(63)						(60)						(3)						—						(126)
Other income, net			66						14						21						—						101
Interest charges			(80)						(47)						(65)						—						(192)
Income taxes			(48)						(37)						(49)						—						(134)
Noncontrolling interests – preferred stock dividends			(1)						—						—						—						(1)
Net income available to common shareholder			$	184					$	105					$	232					$	—					$	521
Interest income			$	22					$	—					$	2					$	—					$	24
Capital expenditures			483						225						419						—						1,127

(a)Significant segment expense that is regularly provided to the CODMs. Intersegment expenses are included within the amounts shown.

42

---

Table of Contents

The following tables present disaggregated revenues by segment at Ameren and Ameren Illinois for the three and nine months ended September 30, 2026 and 2025. Economic factors affect the nature, timing, amount, and uncertainty of revenues and cash flows in a similar manner across customer classes. Revenues from alternative revenue programs have a similar distribution among customer classes as revenues from contracts with customers. Other revenues not associated with contracts with customers are presented in the Other customer classification, along with electric transmission, off-system sales, and capacity revenues.

Ameren

			Ameren Missouri						Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Transmission												Intersegment Eliminations						Ameren
Three Months 2026:
Residential			$	773					$	510					$	—					$	—											$	—					$	1,283
Commercial			571						236						—						—												—						807
Industrial			126						38						—						—												—						164
Other			287						(7)			(a)			—						266												(78)						468
Total electric revenues			$	1,757					$	777					$	—					$	266											$	(78)					$	2,722
Residential			$	12					$	—					$	79					$	—											$	—					$	91
Commercial			6						—						24						—												—						30
Industrial			—						—						2						—												—						2
Other			6						—						31						—												—						37
Total natural gas revenues			$	24					$	—					$	136					$	—											$	—					$	160
Total revenues(b)			$	1,781					$	777					$	136					$	266											$	(78)					$	2,882
Three Months 2025:
Residential			$	702					$	469					$	—					$	—											$	—					$	1,171
Commercial			537						235						—						—												—						772
Industrial			119						46						—						—												—						165
Other			327						(51)			(a)			—						240												(61)						455
Total electric revenues			$	1,685					$	699					$	—					$	240											$	(61)					$	2,563
Residential			$	9					$	—					$	70					$	—											$	—					$	79
Commercial			5						—						21						—												—						26
Industrial			—						—						2						—												—						2
Other			6						—						24						—												(1)						29
Total natural gas revenues			$	20					$	—					$	117					$	—											$	(1)					$	136
Total revenues(b)			$	1,705					$	699					$	117					$	240											$	(62)					$	2,699
Nine Months 2026:
Residential			$	1,598					$	1,209					$	—					$	—											$	—					$	2,807
Commercial			1,254						629						—						—												—						1,883
Industrial			292						145						—						—												—						437
Other			558						66			(a)			—						722												(203)						1,143
Total electric revenues			$	3,702					$	2,049					$	—					$	722											$	(203)					$	6,270
Residential			$	76					$	—					$	504					$	—											$	—					$	580
Commercial			33						—						139						—												—						172
Industrial			3						—						10						—												—						13
Other			21						—						95						—												(1)						115
Total natural gas revenues			$	133					$	—					$	748					$	—											$	(1)					$	880
Total revenues(b)			$	3,835					$	2,049					$	748					$	722											$	(204)					$	7,150

43

---

Table of Contents

			Ameren Missouri						Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Transmission												Intersegment Eliminations						Ameren
Nine Months 2025:
Residential			$	1,483					$	1,132					$	—					$	—											$	—					$	2,615
Commercial			1,154						596						—						—												—						1,750
Industrial			269						144						—						—												—						413
Other			987						(28)			(a)			—						658												(172)						1,445
Total electric revenues			$	3,893					$	1,844					$	—					$	658											$	(172)					$	6,223
Residential			$	65					$	—					$	486					$	—											$	—					$	551
Commercial			29						—						126						—												—						155
Industrial			3						—						9						—												—						12
Other			12						—						65						—												(1)						76
Total natural gas revenues			$	109					$	—					$	686					$	—											$	(1)					$	794
Total revenues(b)			$	4,002					$	1,844					$	686					$	658											$	(173)					$	7,017

(a)Includes over-recoveries of various riders.

(b)The following table presents increases/(decreases) in revenues from alternative revenue programs and other revenues not from contracts with customers for the three and nine months ended September 30, 2026 and 2025:

			Ameren Missouri						Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Transmission						Intersegment Eliminations						Ameren
Three Months 2026:
Revenues from alternative revenue programs			$	(2)					$	(188)					$	(6)					$	(18)					$	—					$	(214)
Other revenues not from contracts with customers			2						5						—						—						(2)						5
Three Months 2025:
Revenues from alternative revenue programs			$	—					$	(187)					$	(10)					$	(12)					$	—					$	(209)
Other revenues not from contracts with customers			2						3						—						—						—						5
Nine Months 2026:
Revenues from alternative revenue programs			$	(5)					$	(116)					$	21					$	(25)					$	—					$	(125)
Other revenues not from contracts with customers			6						10						2						—						(4)						14
Nine Months 2025:
Revenues from alternative revenue programs			$	(4)					$	(174)					$	(6)					$	(21)					$	—					$	(205)
Other revenues not from contracts with customers			5						11						2						—						(4)						14

44

---

Table of Contents

Ameren Illinois

			Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Illinois Transmission						Intersegment Eliminations						Ameren Illinois
Three Months 2026:
Residential			$	510					$	79					$	—					$	—					$	589
Commercial			236						24						—						—						260
Industrial			38						2						—						—						40
Other			(7)			(a)			31						196						(56)						164
Total revenues(b)			$	777					$	136					$	196					$	(56)					$	1,053
Three Months 2025:
Residential			$	469					$	70					$	—					$	—					$	539
Commercial			235						21						—						—						256
Industrial			46						2						—						—						48
Other			(51)			(a)			24						176						(46)						103
Total revenues(b)			$	699					$	117					$	176					$	(46)					$	946
Nine Months 2026:
Residential			$	1,209					$	504					$	—					$	—					$	1,713
Commercial			629						139						—						—						768
Industrial			145						10						—						—						155
Other			66			(a)			95						528						(145)						544
Total revenues(b)			$	2,049					$	748					$	528					$	(145)					$	3,180
Nine Months 2025:
Residential			$	1,132					$	486					$	—					$	—					$	1,618
Commercial			596						126						—						—						722
Industrial			144						9						—						—						153
Other			(28)			(a)			65						482						(123)						396
Total revenues(b)			$	1,844					$	686					$	482					$	(123)					$	2,889

(a)Includes over-recoveries of various riders.

(b)The following table presents increases/(decreases) in revenues from alternative revenue programs and other revenues not from contracts with customers for the Ameren Illinois segments for the three and nine months ended September 30, 2026 and 2025:

			Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Illinois Transmission						Ameren Illinois
Three Months 2026:
Revenues from alternative revenue programs			$	(188)					$	(6)					$	(17)					$	(211)
Other revenues not from contracts with customers			5						—						—						5
Three Months 2025:
Revenues from alternative revenue programs			$	(187)					$	(10)					$	(12)					$	(209)
Other revenues not from contracts with customers			3						—						—						3
Nine Months 2026:
Revenues from alternative revenue programs			$	(116)					$	21					$	(23)					$	(118)
Other revenues not from contracts with customers			10						2						—						12
Nine Months 2025:
Revenues from alternative revenue programs			$	(174)					$	(6)					$	(20)					$	(200)
Other revenues not from contracts with customers			11						2						—						13

45

---

Table of Contents

ITEM 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS.

The following discussion should be read in conjunction with the financial statements contained in this Form 10-Q, as well as Management’s Discussion and Analysis of Financial Condition and Results of Operations and Risk Factors contained in the Form 10-K. We intend for this discussion to provide the reader with information that will assist in understanding our financial statements, the changes in certain key items in those financial statements, and the primary factors that accounted for those changes, as well as how certain accounting principles affect our financial statements. The discussion also provides information about the financial results of our business segments to provide a better understanding of how those segments and their results affect the financial condition and results of operations of Ameren as a whole. Also see the Glossary of Terms and Abbreviations at the front of this report and in the Form 10-K.

Ameren, headquartered in St. Louis, Missouri, is a public utility holding company whose primary assets are its equity interests in its subsidiaries. Ameren’s subsidiaries are separate, independent legal entities with separate businesses, assets, and liabilities. Dividends on Ameren’s common stock and the payment of expenses by Ameren depend on distributions made to it by its subsidiaries. Ameren’s principal subsidiaries are listed below. Ameren also has other subsidiaries that conduct other activities, such as providing shared services.

•Ameren Missouri operates a rate-regulated electric generation, transmission, and distribution business and a rate-regulated natural gas distribution business in Missouri.

•Ameren Illinois operates rate-regulated electric transmission, electric distribution, and natural gas distribution businesses in Illinois.

•ATXI operates a FERC rate-regulated electric transmission business in the MISO.

Ameren’s and Ameren Missouri’s financial statements are prepared on a consolidated basis and therefore include the accounts of their majority-owned subsidiaries. All intercompany transactions have been eliminated. Ameren Illinois has no subsidiaries. All tabular dollar amounts are in millions, unless otherwise indicated.

In addition to presenting results of operations and earnings amounts in total, we present certain information in cents per share. These amounts reflect factors that directly affect Ameren’s earnings. We believe this per share information helps readers to understand the impact of these factors on Ameren’s earnings per diluted share.

OVERVIEW

Net income attributable to Ameren common shareholders in the three months ended September 30, 2026, was $676 million, or $2.42 per diluted share, compared with $640 million, or $2.35 per diluted share, in the year-ago period. Net income attributable to Ameren common shareholders in the nine months ended September 30, 2026, was $1,347 million, or $4.83 per diluted share, compared with $1,204 million, or $4.43 per diluted share, in the year-ago period. Net income was favorably affected for the three and nine months ended September 30, 2026, by increased infrastructure investments across all segments, including infrastructure reflected in electric and natural gas service rates at Ameren Missouri, effective June 1, 2025 and September 1, 2025, respectively, and natural gas rates at Ameren Illinois, effective December 2, 2025. Net income for the three and nine months ended September 30, 2026, was also favorably affected by an increase in earnings from our equity method investments, primarily related to advancing innovative energy technologies, and favorable retail electric sales volumes at Ameren Missouri, excluding customer energy-efficiency programs, primarily due to growth in weather-normalized commercial and residential sales. Additionally, net income for the three months ended September 30, 2026, was favorably affected by increased retail electric sales at Ameren Missouri due to warmer weather. Net income was unfavorably affected for the three and nine months ended September 30, 2026, by increased other operations and maintenance expenses at Ameren Missouri not subject to riders or trackers, largely due to increased reliability measures at the Labadie and Sioux energy centers, increased vegetation management expenses, higher injuries and damage claims, and higher Callaway Energy Center refueling and maintenance outage cost amortization, and increased tax expense at Ameren Transmission due to the revaluation of excess deferred income tax regulatory liabilities in 2025. Earnings in the three and nine months ended September 30, 2026, were also unfavorably affected by higher weighted-average basic common shares outstanding in 2026 and increased financing costs.

Ameren’s strategic plan includes investing in rate-regulated energy infrastructure, enhancing regulatory frameworks and energy policies, and optimizing performance to deliver safe, reliable, and affordable energy for our customers and communities. Ameren remains focused on disciplined cost management and strategic capital allocation. Ameren invested $4.1 billion in its rate-regulated businesses in the nine months ended September 30, 2026.

In June 2026, Ameren Missouri filed a request with the MoPSC seeking approval to increase its annual revenues for electric service by $343 million. The electric rate request is based on a 10.25% return on common equity, a capital structure composed of 52% common equity, a rate base of $16.7 billion, and a test year ended March 31, 2026, with certain pro-forma adjustments expected through an anticipated true-up date of December 31, 2026. The MoPSC proceeding relating to the proposed electric service rate changes will take place over a period of up to 11 months, with a decision by the MoPSC expected by May 2027 and new rates effective by June 2027.

46

---

Table of Contents

In February 2026, the MoPSC issued an order approving a nonunanimous stipulation and agreement related to a requested CCN for the Big Hollow Natural Gas (800-MW facility) and the Big Hollow Battery Energy Storage (400-MW facility) projects. Also in February 2026, Ameren Missouri acquired the Split Rail Solar Project for approximately $0.6 billion and placed it in-service in June 2026. In May 2026, the MoPSC issued an order approving a nonunanimous stipulation and agreement related to a requested CCN for the Reform Solar Project (250-MW facility). In July 2026, Ameren Missouri filed for a CCN to construct the West Alton Natural Gas Project (2,100-MW facility). In October 2026, the MoPSC issued an order approving a nonunanimous stipulation and agreement related to requested CCNs for the Millcreek (250-MW facility), Huck Finn (200-MW facility), and Castle Bluff (95-MW facility) battery energy storage projects and the Ringer (225-MW facility) and Tom Sawyer (175-MW facility) solar projects.

In 2026, Ameren Missouri executed electric service agreements with large load customers under its modified large primary service tariff that was approved in 2025, representing 2.8 gigawatts of demand that is expected to begin materializing in the second half of 2027 and to reach full capacity in 2030. Ameren and Ameren Missouri do not expect a material impact to their results of operations, financial position, or liquidity in 2026 related to these agreements.

In September 2026, Ameren Missouri filed its preferred resource plan with the MoPSC. The plan outlines how Ameren Missouri expects to address load growth opportunities resulting from the electric service agreements discussed above and interest from other entities that are considering either locating or expanding their operations within Ameren Missouri’s service territory. The plan includes significant investment through 2045 in simple- and combined-cycle natural gas, solar, wind, and nuclear generation, as well as battery energy storage and natural gas fuel cells. It also includes retiring all of Ameren Missouri’s coal-fired energy centers by 2042 and certain natural gas-fired energy centers by 2040 to comply with Illinois law. In addition, Ameren Missouri expects to seek and receive NRC approval for an extension of the operating license for the Callaway Energy Center beyond its current 2044 expiration date.

In December 2024, the ICC issued an order in connection with a revised Grid Plan and a revised MYRP filed by Ameren Illinois in March 2024, approving revenue requirements for electric distribution services for 2024 through 2027 of $1,206 million, $1,287 million, $1,367 million, and $1,421 million, respectively. In May 2026, the Illinois Appellate Court for the Fifth Judicial District upheld the ICC’s December 2024 order and orders issued by the ICC in June 2024 and December 2023 following appeals by Ameren Illinois.

In December 2025, the ICC issued an order approving Ameren Illinois’ 2024 electric distribution service revenue requirement reconciliation adjustment filing. In March 2026, Ameren Illinois filed an appeal of the December 2025 order with the Illinois Appellate Court for the Fifth Judicial District and withdrew the appeal in July 2026 as a result of the appellate court decision in the MYRP proceeding discussed above.

In April 2026, Ameren Illinois filed a reconciliation adjustment to its 2025 electric distribution service revenue requirement with the ICC. In August 2026, Ameren Illinois updated its reconciliation adjustment, requesting recovery of $28 million. The adjustment reflects Ameren Illinois’ actual 2025 recoverable costs, 2025 year-end rate base, and a capital structure composed of 50% common equity. The ICC staff has not objected to Ameren Illinois’ updated reconciliation adjustment. In November 2026, the administrative law judges issued a proposed order consistent with Ameren Illinois’ request. An ICC decision is required by December 2026, and any approved adjustment would be collected from customers in 2027.

In May 2026, Ameren Illinois filed an electric energy efficiency plan with the ICC, which includes annual investments in electric energy-efficiency programs up to $192 million, $239 million, and $276 million for 2027, 2028, and 2029, respectively. The ICC has the ability to reduce the amount of electric energy-efficiency savings goals in future program years if there are insufficient cost-effective programs available, which could reduce Ameren Illinois’ investments in electric energy-efficiency programs. A decision by the ICC in this proceeding is expected in November 2026.

In November 2025, the ICC issued an order in Ameren Illinois’ January 2025 natural gas delivery service regulatory rate review, which resulted in an increase to Ameren Illinois’ annual revenues for natural gas delivery service of $79 million based on a 9.60% ROE, a capital structure composed of 50% common equity, a 2026 future test year, and a rate base of $3.2 billion. The order reflected a reduction of $75 million of planned distribution and transmission capital investments included in Ameren Illinois’ future test year request. The new rates became effective in December 2025. In January 2026, Ameren Illinois filed an appeal of the ICC’s November 2025 order to the Illinois Appellate Court for the Fifth Judicial District. The appeal challenged the inclusion of the non-service cost component of the net periodic benefit income related to other postretirement benefits in the annual revenue requirement and the $75 million reduction of planned capital investments, among other things. The court is under no deadline to address the appeal.

For further information on the matters discussed above, see Note 2 – Rate and Regulatory Matters under Part I, Item 1, of this report, and the Outlook section below.

47

---

Table of Contents

RESULTS OF OPERATIONS

Our results of operations and financial position are affected by many factors. Economic conditions, energy-efficiency investments by our customers and by us, technological advances, distributed generation, and the actions of key customers can significantly affect the demand for our services. Ameren and Ameren Missouri results are also affected by seasonal fluctuations in winter heating and summer cooling demands and by weather conditions, such as storms, as well as by energy center maintenance outages. Additionally, fluctuations in interest rates and conditions in the capital and credit markets affect our cost of borrowing, our pension and postretirement benefits costs, the cash surrender value of COLI, the fair value of equity method investments, and the asset value of Ameren Missouri’s nuclear decommissioning trust fund. Almost all of Ameren’s revenues are subject to state or federal regulation. This regulation has a material impact on the rates we charge customers for our services. Our results of operations, financial position, and liquidity are affected by our ability to align our overall spending, both operating and capital, with the frameworks established by our regulators. See Note 2 – Rate and Regulatory Matters under Part I, Item 1, of this report and Note 2 – Rate and Regulatory Matters under Part II, Item 8, of the Form 10-K for additional information regarding Ameren Missouri’s, Ameren Illinois’, and ATXI’s regulatory mechanisms.

Ameren Missouri principally uses coal and enriched uranium for fuel in its electric generation operations and purchases natural gas for its customers. Ameren Illinois purchases power and natural gas for its customers. The prices for these commodities can fluctuate significantly because of the global economic and political environment, weather, supply, demand, and many other factors. We have natural gas cost recovery mechanisms for our Illinois and Missouri natural gas distribution businesses, a purchased power cost recovery mechanism for Ameren Illinois’ electric distribution business, and a FAC for Ameren Missouri’s electric business.

We employ various risk management strategies to reduce our exposure to commodity and interest rate risk as well as other risks inherent in our business. The reliability of Ameren Missouri’s energy centers and our transmission and distribution systems, and the level and timing of operations and maintenance costs and capital investment, are key factors that we seek to manage in order to optimize our results of operations, financial position, and liquidity.

Earnings Summary

The following table presents a summary of Ameren’s earnings for the three and nine months ended September 30, 2026 and 2025:

			Three Months												Nine Months
			2026						2025						2026						2025
Net income attributable to Ameren common shareholders			$	676					$	640					$	1,347					$	1,204
Earnings per common share – diluted			2.42						2.35						4.83						4.43

Net income attributable to Ameren common shareholders increased $36 million and earnings per diluted share increased 7 cents in the three months ended September 30, 2026, compared with the year-ago period. The increase was due to net income increases of $64 million and $15 million at Ameren Missouri and Ameren Illinois Electric Distribution, respectively, and a decrease in net loss of $6 million at Ameren Illinois Natural Gas. The above increases were partially offset by a $41 million reduction in net income at Ameren Transmission. Net income was further impacted by an increase in net loss of $8 million for activity not reported as part of a segment, primarily at Ameren (parent).

Net income attributable to Ameren common shareholders increased $143 million and earnings per diluted share increased 40 cents in the nine months ended September 30, 2026, compared with the year-ago period. The increase was due to net income increases of $105 million, $24 million, and $19 million at Ameren Missouri, Ameren Illinois Electric Distribution, and Ameren Illinois Natural Gas, respectively. The above increases were partially offset by a $22 million reduction in net income at Ameren Transmission. Net income was further impacted by a decrease in net loss of $17 million for activity not reported as part of a segment, primarily at Ameren (parent).

48

---

Table of Contents

Earnings per diluted share were favorably affected in the three and nine months ended September 30, 2026, compared to the year-ago periods (except where a specific period is referenced), by:

•a higher allowance for equity funds used during construction and increased base rate revenues at Ameren Missouri for the inclusion of previously deferred interest charges under PISA pursuant to the April 2025 MoPSC electric rate order, partially offset by lower interest deferrals associated with the PISA (9 cents and 24 cents per share, respectively);

•an increase in earnings from our equity method investments, primarily related to advancing innovative energy technologies in 2026 compared with a net loss on those investments in 2025 (9 cents and 18 cents per share, respectively);

•equity return on increased rate base investments at Ameren Transmission and Ameren Illinois Electric Distribution (6 cents and 16 cents per share, respectively);

•increased base rate revenues at Ameren Missouri, pursuant to the April 2025 MoPSC electric rate order, effective June 1, 2025, partially offset by higher depreciation and amortization and interest expenses in base rates (12 cents per share in the nine months ended September 30, 2026);

•increased base rate revenues at Ameren Illinois Natural Gas, pursuant to the November 2025 ICC natural gas rate order, effective December 2, 2025, partially offset by increased operations and maintenance, depreciation and amortization, and interest expenses included in base rates (3 cents and 9 cents per share, respectively);

•increased retail electric sales volumes at Ameren Missouri, excluding customer energy-efficiency programs, primarily due to warmer summer temperatures in the three month period ended September 30, 2026, and growth in weather-normalized commercial and residential sales volumes in the nine month period ended September 30, 2026 (estimated at 15 cents and 9 cents per share, respectively);

•increased base rate revenues at Ameren Missouri’s natural gas business, pursuant to the July 2025 MoPSC natural gas rate order, effective September 1, 2025, partially offset by higher depreciation and amortization expenses included in base rates (1 cent and 5 cents per share, respectively); and

•higher revenue at Ameren Missouri resulting from the absence in 2026 of a deferral associated with the Rush Island Energy Center (4 cents per share in the nine months ended September 30, 2026).

Earnings per diluted share were unfavorably affected in the three and nine months ended September 30, 2026, compared to the year-ago periods by:

•increased other operations and maintenance expenses at Ameren Missouri not subject to riders or trackers, largely due to increased reliability measures at the Labadie and Sioux energy centers, increased vegetation management expenses, higher injuries and damage claims, and higher Callaway Energy Center refueling and maintenance outage cost amortization (10 cents and 24 cents per share, respectively);

•the absence in 2026 of a decrease in income tax expense at Ameren Transmission resulting from the revaluation of excess deferred income tax regulatory liabilities, resulting from TCJA for FERC-regulated jurisdictions, related to ratemaking treatment of net operating loss carryforwards by affiliates under a tax allocation agreement, see Note 12 – Income Taxes under Part I, Item 1, of this report for additional information (18 cents per share for both periods);

•increased weighted-average basic common shares outstanding resulting from issuances of common shares (6 cents and 12 cents per share, respectively); and

•increased financing costs, primarily at Ameren Missouri and Ameren (parent), largely due to higher rates on higher long-term debt balances (5 cents and 9 cents per share, respectively).

The cents per share variances above are presented based on the weighted-average basic common shares outstanding in the three and nine months ended September 30, 2025, and do not reflect the impact of dilution on earnings per share, unless otherwise noted. The amounts above other than variances related to income taxes have been presented net of income taxes using Ameren’s 2026 blended federal and state statutory tax rate of 26%. For additional details regarding the Ameren Companies’ results of operations, including explanations of Operating Revenues for both Electric Revenues and Natural Gas Revenues; Fuel and Purchased Power Expenses; Other Operations and Maintenance Expenses; Depreciation and Amortization Expenses; Taxes Other Than Income Taxes; Other Income, Net; Interest Charges; and Income Taxes, see the major headings below.

49

---

Table of Contents

Below is Ameren’s table of income statement components by segment for the three and nine months ended September 30, 2026 and 2025:

			Ameren Missouri						Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Transmission						Other / Intersegment Eliminations						Ameren
Three Months 2026:
Electric revenues			$	1,757					$	777					$	—					$	266					$	(78)					$	2,722
Natural gas revenues			24						—						136						—						—						160
Fuel and purchased power			(509)						(360)						—						—						60						(809)
Natural gas purchased for resale			(5)						—						(23)						—						—						(28)
Other operations and maintenance expenses			(274)						(182)						(58)						(34)						13						(535)
Depreciation and amortization expenses			(246)						(100)						(34)						(55)						(1)						(436)
Taxes other than income taxes			(129)						(23)						(17)						(2)						(3)						(174)
Operating income (loss)			618						112						4						175						(9)						900
Other income, net			58						17						3						6						28						112
Interest charges			(82)						(30)						(18)						(32)						(54)						(216)
Income (taxes) benefit			(11)						(27)						4						(39)						(46)						(119)
Net income (loss)			583						72						(7)						110						(81)						677
Noncontrolling interests – preferred stock dividends			(1)						—						—						—						—						(1)
Net income (loss) attributable to Ameren common shareholders			$	582					$	72					$	(7)					$	110					$	(81)					$	676
Three Months 2025:
Electric revenues			$	1,685					$	699					$	—					$	240					$	(61)					$	2,563
Natural gas revenues			20						—						117						—						(1)						136
Fuel and purchased power			(487)						(330)						—						—						49						(768)
Natural gas purchased for resale			(6)						—						(19)						—						—						(25)
Other operations and maintenance expenses			(260)						(171)						(55)						(19)						3						(502)
Depreciation and amortization expenses			(239)						(92)						(33)						(49)						(2)						(415)
Taxes other than income taxes			(122)						(22)						(15)						(3)						(2)						(164)
Operating income (loss)			591						84						(5)						169						(14)						825
Other income (expense), net			45						20						4						(3)						10						76
Interest charges			(85)						(28)						(16)						(31)						(48)						(208)
Income (taxes) benefit			(32)						(19)						4						16						(21)						(52)
Net income (loss)			519						57						(13)						151						(73)						641
Noncontrolling interests – preferred stock dividends			(1)						—						—						—						—						(1)
Net income (loss) attributable to Ameren common shareholders			$	518					$	57					$	(13)					$	151					$	(73)					$	640

50

---

Table of Contents

			Ameren Missouri						Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Transmission						Other / Intersegment Eliminations						Ameren
Nine Months 2026:
Electric revenues			$	3,702					$	2,049					$	—					$	722					$	(203)					$	6,270
Natural gas revenues			133						—						748						—						(1)						880
Fuel and purchased power			(1,041)						(864)						—						—						156						(1,749)
Natural gas purchased for resale			(46)						—						(192)						—						—						(238)
Other operations and maintenance expenses			(820)						(507)						(182)						(74)						36						(1,547)
Depreciation and amortization expenses			(694)						(294)						(101)						(160)						(5)						(1,254)
Taxes other than income taxes			(325)						(66)						(63)						(7)						(10)						(471)
Operating income (loss)			909						318						210						481						(27)						1,891
Other income, net			171						54						10						19						66						320
Interest charges			(247)						(86)						(51)						(94)						(151)						(629)
Income (taxes) benefit			(15)						(77)						(45)						(102)						8						(231)
Net income (loss)			818						209						124						304						(104)						1,351
Noncontrolling interests – preferred stock dividends			(3)						(1)						—						—						—						(4)
Net income (loss) attributable to Ameren common shareholders			$	815					$	208					$	124					$	304					$	(104)					$	1,347
Nine Months 2025:
Electric revenues			$	3,893					$	1,844					$	—					$	658					$	(172)					$	6,223
Natural gas revenues			109						—						686						—						(1)						794
Fuel and purchased power			(1,431)						(765)						—						—						132						(2,064)
Natural gas purchased for resale			(45)						—						(188)						—						—						(233)
Other operations and maintenance expenses			(748)						(493)						(165)						(56)						15						(1,447)
Depreciation and amortization expenses			(642)						(276)						(98)						(146)						(6)						(1,168)
Taxes other than income taxes			(300)						(63)						(60)						(7)						(9)						(439)
Operating income (loss)			836						247						175						449						(41)						1,666
Other income, net			135						66						14						14						28						257
Interest charges			(215)						(80)						(47)						(89)						(139)						(570)
Income (taxes) benefit			(43)						(48)						(37)						(48)						31						(145)
Net income (loss)			713						185						105						326						(121)						1,208
Noncontrolling interests – preferred stock dividends			(3)						(1)						—						—						—						(4)
Net income (loss) attributable to Ameren common shareholders			$	710					$	184					$	105					$	326					$	(121)					$	1,204

51

---

Table of Contents

Below is Ameren Illinois’ table of income statement components by segment for the three and nine months ended September 30, 2026 and 2025:

			Ameren Illinois Electric Distribution						Ameren Illinois  Natural Gas						Ameren Illinois Transmission						Other / Intersegment Eliminations						Ameren Illinois
Three Months 2026:
Electric revenues			$	777					$	—					$	196					$	(56)					$	917
Natural gas revenues			—						136						—						—						136
Purchased power			(360)						—						—						56						(304)
Natural gas purchased for resale			—						(23)						—						—						(23)
Other operations and maintenance expenses			(182)						(58)						(25)						—						(265)
Depreciation and amortization expenses			(100)						(34)						(41)						—						(175)
Taxes other than income taxes			(23)						(17)						(2)						—						(42)
Operating income			112						4						128						—						244
Other income, net			17						3						5						—						25
Interest charges			(30)						(18)						(24)						—						(72)
Income (taxes) benefit			(27)						4						(30)						—						(53)
Net income (loss) attributable to common shareholders			$	72					$	(7)					$	79					$	—					$	144
Three Months 2025:
Electric revenues			$	699					$	—					$	176					$	(46)					$	829
Natural gas revenues			—						117						—						—						117
Purchased power			(330)						—						—						46						(284)
Natural gas purchased for resale			—						(19)						—						—						(19)
Other operations and maintenance expenses			(171)						(55)						(15)						—						(241)
Depreciation and amortization expenses			(92)						(33)						(37)						—						(162)
Taxes other than income taxes			(22)						(15)						(1)						—						(38)
Operating income (loss)			84						(5)						123						—						202
Other income, net			20						4						6						—						30
Interest charges			(28)						(16)						(23)						—						(67)
Income (taxes) benefit			(19)						4						(2)						—						(17)
Net income (loss) attributable to common shareholders			$	57					$	(13)					$	104					$	—					$	148

52

---

Table of Contents

			Ameren Illinois Electric Distribution						Ameren Illinois  Natural Gas						Ameren Illinois Transmission						Other / Intersegment Eliminations						Ameren Illinois
Nine Months 2026:
Electric revenues			$	2,049					$	—					$	528					$	(145)					$	2,432
Natural gas revenues			—						748						—						—						748
Purchased power			(864)						—						—						145						(719)
Natural gas purchased for resale			—						(192)						—						—						(192)
Other operations and maintenance expenses			(507)						(182)						(56)						—						(745)
Depreciation and amortization expenses			(294)						(101)						(122)						—						(517)
Taxes other than income taxes			(66)						(63)						(4)						—						(133)
Operating income			318						210						346						—						874
Other income, net			54						10						16						—						80
Interest charges			(86)						(51)						(72)						—						(209)
Income taxes			(77)						(45)						(75)						—						(197)
Net income			209						124						215						—						548
Preferred stock dividends			(1)						—						—						—						(1)
Net income attributable to common shareholder			$	208					$	124					$	215					$	—					$	547
Nine Months 2025:
Electric revenues			$	1,844					$	—					$	482					$	(123)					$	2,203
Natural gas revenues			—						686						—						—						686
Purchased power			(765)						—						—						123						(642)
Natural gas purchased for resale			—						(188)						—						—						(188)
Other operations and maintenance expenses			(493)						(165)						(44)						—						(702)
Depreciation and amortization expenses			(276)						(98)						(110)						—						(484)
Taxes other than income taxes			(63)						(60)						(3)						—						(126)
Operating income			247						175						325						—						747
Other income, net			66						14						21						—						101
Interest charges			(80)						(47)						(65)						—						(192)
Income taxes			(48)						(37)						(49)						—						(134)
Net income			185						105						232						—						522
Preferred stock dividends			(1)						—						—						—						(1)
Net income attributable to common shareholder			$	184					$	105					$	232					$	—					$	521

53

---

Table of Contents

Operating Revenues

The following table presents the increases (decreases) by Ameren segment for electric and natural gas revenues for the three and nine months ended September 30, 2026, compared with the year-ago periods:

Three Months			Ameren Missouri						Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Transmission(a)						Other /Intersegment Eliminations						Ameren
Electric revenue change:
Base rates (estimate)(b)			$	—					$	23					$	—					$	26					$	—					$	49
Effect of weather (estimate)(c)			39						—						—						—						—						39
Retail sales volumes and changes in customer usage patterns (normalized for the estimated effects of weather and MEEIA)			17						—						—						—						—						17
Transmission service charges (not included in the FAC)			2						—						—						—						—						2
Off-system sales, capacity, transmission, and FAC revenues, net			(37)						—						—						—						—						(37)
Ameren Illinois energy-efficiency program investment revenues			—						3						—						—						—						3
Electric deferred income tax adjustment(d)			—						10						—						—						—						10
Customer generation rebate program revenues			—						8						—						—						—						8
RESRAM(e)			(6)						—						—						—						—						(6)
Other			2						2						—						—						(6)						(2)
Cost recovery mechanisms – offset in fuel and purchased power(f)			51						30						—						—						(11)						70
Other cost recovery mechanisms(g)			4						2						—						—						—						6
Total electric revenue change			$	72					$	78					$	—					$	26					$	(17)					$	159
Natural gas revenue change:
Base rates (estimate)			$	5					$	—					$	9					$	—					$	—					$	14
Change in rate design (estimate)			—						—						4						—						—						4
Other			—						—						—						—						1						1
Cost recovery mechanisms – offset in natural gas purchased for resale(f)			(1)						—						4						—						—						3
Other cost recovery mechanisms(g)			—						—						2						—						—						2
Total natural gas revenue change			$	4					$	—					$	19					$	—					$	1					$	24
Nine Months
Electric revenue change:
Base rates (estimate)(b)			$	118					$	66					$	—					$	64					$	—					$	248
Effect of weather (estimate)(c)			9						—						—						—						—						9
Retail sales volumes and changes in customer usage patterns (normalized for the estimated effects of weather and MEEIA)			29						—						—						—						—						29
Transmission service charges (not included in the FAC)			8						—						—						—						—						8
Off-system sales, capacity, and FAC revenues, net			(515)						—						—						—						—						(515)
Ameren Illinois energy-efficiency program investment revenues			—						8						—						—						—						8
Electric deferred income tax adjustment(d)			—						21						—						—						—						21
Rush Island Energy Center base rate revenue deferral			26						—						—						—						—						26
Customer generation rebate program revenues			—						15						—						—						—						15
RESRAM(e)			6						—						—						—						—						6
Other			6						2						—						—						(7)						1
Cost recovery mechanisms – offset in fuel and purchased power(f)			110						99						—						—						(24)						185
Other cost recovery mechanisms(g)			12						(6)						—						—						—						6
Total electric revenue change			$	(191)					$	205					$	—					$	64					$	(31)					$	47
Natural gas revenue change:
Base rates (estimate)			$	22					$	—					$	52					$	—					$	—					$	74
Change in rate design (estimate)			—						—						3						—						—						3
Effect of weather (estimate)(c)			(3)						—						—						—						—						(3)
Other			1						—						(1)						—						—						—
Cost recovery mechanisms – offset in natural gas purchased for resale(f)			4						—						4						—						—						8
Other cost recovery mechanisms(g)			—						—						4						—						—						4
Total natural gas revenue change			$	24					$	—					$	62					$	—					$	—					$	86

(a)Includes an increase in transmission revenues of $20 million and $46 million at Ameren Illinois for the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods.

54

---

Table of Contents

(b)For Ameren Illinois Electric Distribution and Ameren Transmission, base rates include increases or decreases in operating revenues related to the revenue requirement reconciliation adjustment under the MYRP and formula rates, respectively. For Ameren Missouri, base rates exclude an increase for the recovery of lost electric revenue, less the associated fuel and purchased power expenses, resulting from the MEEIA customer energy-efficiency programs and a decrease in base rates for RESRAM. These changes in Ameren Missouri base rates are included in the “Retail sales volumes and changes in customer usage patterns (normalized for the estimated effects of weather and MEEIA)” and “Cost recovery mechanisms - offset in fuel and purchased power” line items, respectively.

(c)Represents the estimated variation resulting primarily from changes in cooling and heating degree-days on electric and natural gas demand compared with the year-ago periods; this variation is based on temperature readings from National Oceanic and Atmospheric Administration weather stations at local airports in our service territories.

(d)The electric deferred income tax adjustment relates to certain excess deferred income taxes that were amortized through 2025. Offsetting expense increases or decreases are reflected within the “Income Taxes” section of the statement of income. This item has no overall impact on earnings.

(e)Changes in RESRAM revenues are largely offset in “Fuel and purchased power,” “Other operations and maintenance,” “Depreciation and amortization,” “Taxes other than income taxes,” or “Income taxes” on the statement of income.

(f)Electric and natural gas revenue changes are offset by corresponding changes in “Fuel and purchased power” and “Natural gas purchased for resale” on the statement of income. For the three and nine months ended September 30, 2026, activity in Other/Intersegment Eliminations of $11 million and $24 million, respectively, was primarily due to the changes in Ameren Transmission revenue from transmission services provided to Ameren Illinois Electric Distribution (-$10 million and -$22 million, respectively). See Note 14 – Segment Information under Part I, Item 1, of this report for additional information on intersegment eliminations. These items have no overall impact on earnings.

(g)Offsetting expense increases or decreases are reflected in “Other operations and maintenance,” “Taxes other than income taxes,” or “Income taxes” on the statement of income. These items have no overall impact on earnings.

Electric Revenues

Ameren

Ameren’s electric revenues increased $159 million, or 6%, for the three months ended September 30, 2026, compared with the year-ago period, due to increased revenues at Ameren Illinois Electric Distribution, Ameren Missouri, and Ameren Transmission. For the nine months ended September 30, 2026, Ameren’s electric revenues increased $47 million, or 1%, compared with the year-ago period, primarily due to increased revenues at Ameren Illinois Electric Distribution and Ameren Transmission, partially offset by decreased revenues at Ameren Missouri.

Ameren Transmission

Ameren Transmission’s electric revenues increased $26 million, or 11%, and $64 million, or 10%, for the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods. Revenues were affected by higher recoverable expenses (+$17 million and +$39 million, respectively) and return on higher rate base (+$9 million and +$25 million, respectively), as evidenced by a 9% increase in rate base used to calculate the revenue requirement.

Ameren Missouri

Ameren Missouri’s electric revenues increased $72 million, or 4%, and decreased $191 million, or 5%, for the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods.

“Off-system sales, capacity, transmission, and FAC revenues, net” decreased $37 million and $515 million, respectively, for the three and nine months ended September 30, 2026, primarily due to spring and summer capacity prices decreasing from $720 and $667 per MW-day in 2025 to $70 and $424 per MW-day, respectively, in 2026 as a result of the annual MISO auctions. The decrease in “Off-system sales, capacity, transmission, and FAC revenues, net” is largely offset by a decrease in fuel and purchased power expenses under “Energy costs”.

The following items increased Ameren Missouri’s electric revenues for the three and nine months ended September 30, 2026 (except where a specific period is referenced):

•Higher electric base rates, excluding the change in base rates for the MEEIA customer energy-efficiency programs and the RESRAM, resulting from the April 2025 MoPSC electric rate order effective June 1, 2025, increased revenues an estimated $118 million for the nine months ended September 30, 2026.

•Revenues associated with “Cost recovery mechanisms – offset in fuel and purchased power” increased $51 million and $110 million, respectively, due to increased revenue related to the recovery of costs previously deferred under the FAC. The changes to “Cost recovery mechanisms - offset in fuel and purchased power” are fully offset by changes to “Cost recovery mechanisms - offset in electric revenue” in fuel and purchased power.

•Excluding the estimated effects of weather and the MEEIA customer energy-efficiency programs, electric revenues increased an estimated $17 million and $29 million, respectively, primarily due to increased weather-normalized commercial and residential retail sales volumes.

•For the nine months ended September 30, 2026, revenues increased $26 million due to the absence of the deferral of base rate revenues to a regulatory liability related to the Rush Island Energy Center following its October 15, 2024 retirement date, in accordance with the June 2024 MoPSC financing order. The deferral ended with new rates effective June 1, 2025.

55

---

Table of Contents

•The effect of weather increased revenues an estimated $39 million and $9 million, respectively, due to warmer summer temperatures, partially offset by milder winter and spring temperatures.

Ameren Illinois

Ameren Illinois’ electric revenues increased $88 million, or 11%, and $229 million, or 10%, for the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods, driven by increased revenues at Ameren Illinois Electric Distribution and Ameren Illinois Transmission.

Ameren Illinois Electric Distribution

Ameren Illinois Electric Distribution’s revenues increased $78 million, or 11%, and $205 million, or 11%, for the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods.

The following items increased Ameren Illinois Electric Distribution’s revenues for the three and nine months ended September 30, 2026:

•Revenues associated with “Cost recovery mechanisms – offset in fuel and purchased power” increased $30 million and $99 million, respectively, due to increased purchased power expenses recovered from customers. The increase in electric revenues is fully offset by an increase in purchased power expenses under cost recovery mechanisms for purchased power, as discussed below.

•Base rates increased revenues by $23 million and $66 million, respectively, due to higher recoverable non-purchased power expenses (+$18 million and +$55 million, respectively) and return on higher rate base (+$5 million and +$11 million, respectively).

•Revenues increased $10 million and $21 million, respectively, due to the absence of amortization of certain excess deferred income taxes in 2025.

•Revenues increased $8 million and $15 million, respectively, due to the recovery of (+$5 million and +$10 million, respectively) and return on (+$3 million and +$5 million, respectively) increased customer generation rebates under performance-based formula ratemaking.

•Revenues increased $3 million and $8 million, respectively, due to the recovery of (+$2 million and +$6 million, respectively) and return on (+$1 million and +$2 million, respectively) increased energy-efficiency program investments under performance-based formula ratemaking.

Other cost recovery mechanisms decreased revenues $6 million for the nine months ended September 30, 2026, primarily due to a lower amount of customer bad debt costs included in customer rates pursuant to the associated rider.

Ameren Illinois Transmission

Ameren Illinois Transmission’s revenues increased $20 million, or 11%, and $46 million, or 10%, for the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods. Base rate revenues were primarily affected by higher recoverable expenses (+$14 million and +$31 million, respectively) and return on higher rate base (+$6 million and +$15 million, respectively), as evidenced by an 8% increase in rate base used to calculate the revenue requirement.

Ameren

Ameren’s natural gas revenues increased $24 million, or 18%, and $86 million, or 11%, for the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods, due to increased revenues at Ameren Illinois Natural Gas and Ameren Missouri, as discussed below.

Ameren Missouri

Ameren Missouri’s natural gas revenues were comparable for the three months ended September 30, 2026, and increased $24 million, or 22%, for the nine months ended September 30, 2026, compared with the year-ago period, primarily due to the effect of higher natural gas base rates as a result of the July 2025 MoPSC natural gas rate order effective September 1, 2025.

Ameren Illinois Natural Gas

Ameren Illinois Natural Gas’ revenues increased $19 million, or 16%, and $62 million, or 9%, for the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods. Base rate revenue increased an estimated $9 million and $52 million, respectively, for the three and nine months ended September 30, 2026, due to higher natural gas rates as a result of the November 2025 natural gas rate order, effective December 2, 2025. See Note 2 – Rate and Regulatory Matters under Part I, Item 1, of this report for additional information regarding the November 2025 natural gas rate order.

56

---

Table of Contents

Fuel and Purchased Power

The following table presents the increases (decreases) by Ameren segment for fuel and purchased power for the three and nine months ended September 30, 2026, compared with the year-ago periods:

Three Months			Ameren Missouri						Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Transmission						Other /Intersegment Eliminations						Ameren
Fuel and purchased power change:
Energy costs (excluding the estimated effect of weather)			$	(36)					$	—					$	—					$	—					$	—					$	(36)
Retail sales volume (excluding the estimated effect of weather)			1						—						—						—						—						1
Effect of weather (estimate)(a)			4						—						—						—						—						4
Transmission service charges (not included in the FAC)			2						—						—						—						—						2
Cost recovery mechanisms – offset in electric revenue(b)			51						30						—						—						(11)						70
Total fuel and purchased power change			$	22					$	30					$	—					$	—					$	(11)					$	41
Nine Months
Fuel and purchased power change:
Energy costs (excluding the estimated effect of weather)			$	(514)					$	—					$	—					$	—					$	—					$	(514)
Retail sales volume (excluding the estimated effect of weather)			4						—						—						—						—						4
Effect of weather (estimate)(a)			(1)						—						—						—						—						(1)
Transmission service charges (not included in the FAC)			7						—						—						—						—						7
Effect of higher net energy costs included in base rates			5						—						—						—						—						5
Other			(1)						—						—						—						—						(1)
Cost recovery mechanisms – offset in electric revenue(b)			110						99						—						—						(24)						185
Total fuel and purchased power change			$	(390)					$	99					$	—					$	—					$	(24)					$	(315)

(a)Represents the estimated variation resulting primarily from changes in cooling and heating degree-days on electric demand compared with the year-ago periods; this variation is based on temperature readings from the National Oceanic and Atmospheric Administration weather stations at local airports in our service territories.

(b)“Cost recovery mechanisms — offset in electric revenue” changes are offset by corresponding changes in “Cost recovery mechanisms — offset in fuel and purchased power” in electric revenues. For the three and nine months ended September 30, 2026, activity in Other/Intersegment Eliminations of $11 million and $24 million, respectively, was primarily due to the changes in Ameren Transmission revenue from transmission services provided to Ameren Illinois Electric Distribution (-$10 million and -$22 million, respectively). See Note 14 – Segment Information under Part I, Item 1, of this report for additional information on intersegment eliminations. These items have no overall impact on earnings.

Ameren

Ameren Missouri and Ameren Illinois are generally allowed to pass on to customers prudently incurred costs for fuel and purchased power. Ameren’s electric fuel and purchased power expenses increased $41 million, or 5%, for the three months ended September 30, 2026, and decreased $315 million, or 15%, for the nine months ended September 30, 2026, respectively, compared with the year-ago periods, primarily due to decreased fuel and purchased power expenses at Ameren Missouri, partially offset by increased fuel and purchased power expenses at Ameren Illinois Electric Distribution, as discussed below.

Ameren Missouri

Ameren Missouri’s fuel and purchased power expenses increased $22 million, or 5%, for the three months ended September 30, 2026, and decreased $390 million, or 27%, for the nine months ended September 30, 2026, compared with the year-ago periods. Energy costs decreased $36 million and $514 million, respectively, primarily due to spring and summer capacity prices decreasing from $720 and $667 per MW-day in 2025 to $70 and $424 per MW-day, respectively, in 2026 as a result of the annual MISO auctions. Ameren Missouri’s 5% exposure to net energy cost variances under the FAC increased $1 million in the three and nine months ended September 30, 2026, represented by the difference between “Off-system sales, capacity, transmission, and FAC revenues, net” in electric revenues and “Energy costs (excluding the estimated effect of weather)”. “Cost recovery mechanisms — offset in electric revenue” increased fuel and purchased power expenses $51 million and $110 million, respectively, due to increased recovery of costs previously deferred under the FAC. The changes to “Cost recovery mechanisms - offset in electric revenue” are fully offset by “Cost recovery mechanisms - offset in fuel and purchased power” in electric revenues.

Ameren Illinois Electric Distribution

Ameren Illinois Electric Distribution’s purchased power expenses increased $30 million, or 9%, and $99 million, or 13%, for the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods. This is primarily due to increased energy prices, transmission service charges and volumes. The changes to “Cost recovery mechanisms - offset in electric revenue” are fully offset by changes to “Cost recovery mechanisms - offset in fuel and purchased power” in electric revenues.

57

---

Table of Contents

Natural Gas Purchased for Resale

The following table presents the increases (decreases) by Ameren segment for natural gas purchased for resale for the three and nine months ended September 30, 2026, compared with the year-ago periods:

Three Months			Ameren Missouri						Ameren Illinois Electric Distribution						Ameren Illinois Natural Gas						Ameren Transmission						Other /Intersegment Eliminations						Ameren
Natural gas purchased for resale change:
Cost recovery mechanisms – offset in natural gas revenue(b)			(1)						—						4						—						—						3
Total natural gas purchased for resale change			$	(1)					$	—					$	4					$	—					$	—					$	3
Nine Months
Natural gas purchased for resale change:
Effect of weather (estimate)(a)			$	(3)					$	—					$	—					$	—					$	—					$	(3)
Cost recovery mechanisms – offset in natural gas revenue(b)			4						—						4						—						—						8
Total natural gas purchased for resale change			$	1					$	—					$	4					$	—					$	—					$	5

(a)Represents the estimated variation resulting primarily from changes in cooling and heating degree-days on natural gas demand compared with the year-ago periods; this variation is based on temperature readings from the National Oceanic and Atmospheric Administration weather stations at local airports in our service territories.

(b)Natural gas purchased for resale changes are offset by corresponding changes in “Natural gas revenues” on the statement of income. These items have no overall impact on earnings.

Ameren Missouri and Ameren Illinois are allowed to pass on to customers prudently incurred costs for natural gas purchased for resale. Natural gas purchased for resale expenses were comparable between periods at Ameren, Ameren Missouri, and Ameren Illinois Natural Gas.

58

---

Table of Contents

Other Operations and Maintenance Expenses

Increase (Decrease) by Segment

Overall Ameren Increase of $33 Million (QTD YoY)

Overall Ameren Increase of $100 Million (YTD YoY)

Total by Segment(a)

(a)Includes $34 million and $19 million at Ameren Transmission in the three months ended September 30, 2026 and 2025, respectively. Includes other/intersegment eliminations of $(13) million and $(3) million in the three months ended September 30, 2026 and 2025, respectively. Also includes other/intersegment eliminations of $(36) million and $(15) million in the nine months ended September 30, 2026 and 2025, respectively.

Ameren Missouri

Ameren Illinois Natural Gas

Other/Intersegment Eliminations

Ameren Illinois Electric Distribution

Ameren Transmission

Ameren

Other operations and maintenance expenses increased $33 million and $100 million in the three and nine months ended September 30, 2026, respectively, due to the changes discussed below. In addition to changes by segments discussed below, other operations and maintenance expenses decreased $10 million and $21 million, respectively, for activity not reported as part of a segment, as reflected in “Other/Intersegment Eliminations” above. This is primarily due to a decrease of $5 million and $15 million, respectively, in the elimination of the non-service cost component of net periodic benefit income. The non-service cost component of net periodic benefit cost or income at Ameren Services is allocated to the segments and primarily included in the segments’ other operations and maintenance expenses.

Ameren Transmission

Other operations and maintenance expenses increased $15 million and $18 million in the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods, primarily due to a $10 million increase in software costs.

Ameren Missouri

Other operations and maintenance expenses increased $14 million and $72 million in the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods, primarily due to the following items (except where a specific period is referenced):

•Non-nuclear generation operations and maintenance expenses increased $5 million and $25 million, respectively, primarily due to increased reliability measures at the Labadie and Sioux energy centers.

•Transmission and distribution expenditures, excluding major storm-related expenses, increased $6 million and $20 million, respectively, largely due to increased vegetation management expenditures.

•Callaway Energy Center operating costs increased $11 million in the nine months ended September 30, 2026, primarily due to increased amortization costs from the spring 2025 refueling and maintenance outage.

59

---

Table of Contents

•Injuries and damages increased $9 million in the nine months ended September 30, 2026, due to higher claim expenses.

The increase in other operations and maintenance expenses was partially offset for the nine months ended September 30, 2026, compared with the year-ago period, by a $6 million decrease in major storm-related expenses.

Ameren Illinois

Other operations and maintenance expenses increased $24 million and $43 million in the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods, primarily due to the following items:

Ameren Illinois Electric Distribution

Other operations and maintenance expenses increased $11 million and $14 million in the three and nine months ended September 30, 2026, respectively, primarily due to the following items (except where a specific period is referenced):

•Increased costs associated with customer generation rebates and energy-efficiency program investments under formula ratemaking of $4 million and $10 million, respectively, due to increased amortization of regulatory assets.

•Increased costs of $9 million resulting from expanding programs under CEJA in the nine months ended September 30, 2026.

•Distribution expenditures increased $2 million and $5 million, respectively, largely due to increased vegetation management expenditures.

•Storm-related expenses, including related amortizations of previously deferred amounts, increased $3 million in the three months ended September 30, 2026, due to major storms experienced throughout its service territory in 2026.

The increase in other operations and maintenance expenses was partially offset for the nine months ended September 30, 2026, compared with the year-ago period, due to a $9 million decrease in bad debt expense, primarily due to a reduction in the base level of expense reflected in customer rates under the associated rider, effective June 2025.

Ameren Illinois Natural Gas

Other operations and maintenance expenses were comparable in the three months ended September 30, 2026 and increased $17 million in the nine months ended September 30, 2026, primarily due to increased natural gas storage costs of $8 million and increased customer bad debts of $3 million.

Ameren Illinois Transmission

Other operations and maintenance expenses increased $10 million and $12 million in the three and nine months ended September 30, 2026, respectively, primarily due to an increase of $10 million related to software costs.

60

---

Table of Contents

Depreciation and Amortization Expenses

Increase (Decrease) by Segment

Overall Ameren Increase of $21 Million (QTD YoY)

Overall Ameren Increase of $86 Million (YTD YoY)

Total by Segment(a)

(a)Includes other/intersegment eliminations of $1 million and $2 million in the three months ended September 30, 2026 and 2025, respectively. Also includes other/intersegment eliminations of $5 million and $6 million in the nine months ended September 30, 2026 and 2025, respectively.    

Ameren Missouri

Ameren Illinois Natural Gas

Other/Intersegment Eliminations

Ameren Illinois Electric Distribution

Ameren Transmission

Depreciation and amortization expenses increased $21 million, $13 million, and $7 million in the three months ended September 30, 2026, compared with the year-ago period at Ameren, Ameren Illinois, and Ameren Missouri, respectively, primarily because of additional property, plant, and equipment investments. Depreciation and amortization expenses increased $86 million, $52 million, and $33 million in the nine months ended September 30, 2026 at Ameren, Ameren Missouri, and Ameren Illinois, respectively, primarily because of additional property, plant, and equipment investments. Ameren’s and Ameren Missouri’s depreciation and amortization expenses for the nine months ended September 30, 2026, compared with the year-ago period, were affected by the following:

•Increased depreciation and amortization of $25 million due to the inclusion in base rates of property, plant, and equipment previously eligible for deferral to a regulatory asset under the PISA and RESRAM effective June 1, 2025, pursuant to the April 2025 MoPSC electric rate order.

•Lower net deferrals and increased amortization of prior deferrals under PISA, which increased depreciation and amortization expenses by $7 million.

•Depreciation and amortization rate changes effective June 1, 2025, pursuant to the April 2025 MoPSC electric rate order, which increased depreciation and amortization expenses by $6 million.

•The lower net under-recovery of RESRAM eligible expenses and increased amortization of prior deferrals increased depreciation and amortization expenses by $5 million.

61

---

Table of Contents

Taxes Other Than Income Taxes

Increase (Decrease) by Segment

Overall Ameren Increase of $10 Million (QTD YoY)

Overall Ameren Increase of $32 Million (YTD YoY)

Total by Segment(a)

(a)Includes $2 million, $3 million, $7 million, and $7 million at Ameren Transmission in the three months ended September 30, 2026 and 2025, and in the nine months ended September 30, 2026 and 2025, respectively. Also includes other/intersegment eliminations of $3 million, $2 million, $10 million, and $9 million in the three months ended September 30, 2026 and 2025, and in the nine months ended September 30, 2026 and 2025, respectively.

Ameren Missouri

Ameren Illinois Natural Gas

Other/Intersegment Eliminations

Ameren Illinois Electric Distribution

Ameren Transmission

Taxes other than income taxes increased $10 million and $32 million in the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods, primarily because of an increase of $7 million and $25 million, respectively, at Ameren Missouri. The increase at Ameren Missouri is largely due to an increase in property taxes of $12 million in the nine months ended September 30, 2026. Additionally, gross receipts taxes at Ameren Missouri increased $6 million and $12 million, respectively, resulting from an increase in retail electric base rates and sales volumes.

62

---

Table of Contents

Other Income, Net

Increase (Decrease) by Segment

Overall Ameren Increase of $36 Million (QTD YoY)

Overall Ameren Increase of $63 Million (YTD YoY)

Total by Segment(a)

(a)Includes $3 million and $4 million at Ameren Illinois Natural Gas in the three months ended September 30, 2026 and 2025, respectively. Also includes $6 million and $(3) million at Ameren Transmission in the three months ended September 30, 2026 and 2025, respectively.

Ameren Missouri

Ameren Illinois Natural Gas

Other/Intersegment Eliminations

Ameren Illinois Electric Distribution

Ameren Transmission

See Note 5 – Other Income, Net, under Part I, Item 1, of this report for additional information. See Note 11 – Retirement Benefits under Part I, Item 1, of this report for more information on the non-service cost components of net periodic benefit income.

Other income, net, increased $36 million and $63 million in the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods. In addition to the changes discussed below, other income, net, increased by $18 million and $38 million, respectively, for activity not reported as part of a segment, due to an increase of $24 million and $58 million in income from equity method investments primarily associated with investments to advance innovative energy technologies in the three and nine months ended September 30, 2026. The increase was partially offset by a decrease of $5 million and $15 million, respectively, in the non-service cost component of net periodic benefit income.

Ameren Transmission

Other income, net, increased $9 million and $5 million in the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods, primarily due to an increase of $9 million related to the absence of a 2025 impairment of an equity method investment in the three and nine months ended September 30, 2026.

Ameren Missouri

Other income, net, increased $13 million and $36 million in the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods, primarily due to an increase of $13 million and $43 million, respectively, in the allowance for equity funds used during construction. This increase was partially offset by a decrease of $7 million in the non-service cost component of net periodic benefit income in the nine months ended September 30, 2026.

63

---

Table of Contents

Ameren Illinois

Other income, net, decreased $5 million and $21 million in the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods, primarily due to the decrease of $9 million and $20 million, respectively, in the non-service cost component of net periodic benefit income, largely at Ameren Illinois Electric Distribution and Ameren Illinois Natural Gas. Other income, net, decreased $5 million in the nine months ended September 30, 2026, due to lower interest income on regulatory deferrals, primarily at Ameren Illinois Electric Distribution.

Interest Charges

Increase (Decrease) by Segment

Overall Ameren Increase of $8 Million (QTD YoY)

Overall Ameren Increase of $59 Million (YTD YoY)

Total by Segment

Ameren Missouri

Ameren Illinois Natural Gas

Other/Intersegment Eliminations

Ameren Illinois Electric Distribution

Ameren Transmission

See Note 3 – Short-term Debt and Liquidity under Part I, Item 1, of this report and the Long-term Debt and Equity section below for additional information on short-term borrowings and long-term debt, respectively, discussed below.

Ameren

Interest charges increased $8 million and $59 million in the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods. In addition to changes by segments discussed below, interest charges increased $6 million and $12 million in the three and nine months ended September 30, 2026 at Ameren (parent). The increase is primarily due to issuances net of maturities of long-term debt in March 2025 and March 2026, which increased interest by $4 million and $13 million in the three and nine months ended September 30, 2026, respectively.

Ameren Transmission

Interest charges were comparable between periods.

64

---

Table of Contents

Ameren Missouri

Interest charges were comparable in the three months ended September 30, 2026, and increased $32 million in the nine months ended September 30, 2026, compared with the year-ago period. Interest charges in the nine months ended September 30, 2026, increased primarily due to the issuances of long-term debt in February 2026, June 2026, and April 2025, which increased interest expense by $41 million. Additionally, interest charges increased because the PISA and RESRAM were updated when new customer rates became effective on June 1, 2025, pursuant to the April 2025 MoPSC electric rate order. Lower deferrals resulting from the inclusion in base rates of interest associated with certain property, plant, and equipment previously deferred under the PISA and RESRAM increased interest charges by $8 million. These increases were partially offset by an increase in the borrowed funds capitalized as part of the allowance for funds used during construction, which decreased interest charges by $18 million. This was primarily driven by higher average construction work in progress balances.

Ameren Illinois

Interest charges increased $5 million and $17 million in the three and nine months ended September 30, 2026, respectively, compared with the year-ago periods, primarily due to issuances of long-term debt, partially offset by maturities in the nine months ended September 30, 2026. These increased interest expense by $2 million and $7 million at Ameren Illinois Transmission, $3 million and $7 million at Ameren Illinois Electric Distribution, and $1 million and $4 million at Ameren Illinois Natural Gas for the three and nine months ended September 30, 2026, respectively.

Income Taxes

The following table presents effective income tax rates for the three and nine months ended September 30, 2026 and 2025:

						Three Months(a)												Nine Months(a)
						2026						2025						2026						2025
Ameren						15		%				7		%				14		%				11		%
Ameren Missouri						2		%				6		%				2		%				6		%
Ameren Illinois						27		%				10		%				26		%				20		%
Ameren Illinois Electric Distribution						28		%				25		%				27		%				21		%
Ameren Illinois Natural Gas						29		%				25		%				27		%				26		%
Ameren Illinois Transmission						27		%				2		%				26		%				17		%
Ameren Transmission						26		%				(12)		%				25		%				13		%

(a)Estimate of the annual effective income tax rate adjusted to reflect the tax effect of items discrete to the three and nine months ended September 30, 2026 and 2025.

See Note 12 – Income Taxes under Part I, Item 1, of this report for a reconciliation of the federal statutory corporate income tax rate to the effective income tax rate for the Ameren Companies.

The effective tax rate was higher at Ameren Illinois Electric Distribution in the three and nine months ended September 30, 2026, compared with the year-ago periods, primarily due to a decrease in excess deferred tax amortization pursuant to an ICC order, which was offset by a corresponding increase in electric revenues. The effective tax rate was higher at Ameren Transmission and Ameren Illinois Transmission for the three and nine months ended September 30, 2026, compared with the year-ago periods due to the absence of a revaluation of excess deferred income tax regulatory liabilities in the third quarter of 2025. In 2024, the IRS issued a series of private letter rulings to another taxpayer, which provided guidance on applying IRS normalization rules to the calculation of tax benefits applicable to the ratemaking treatment related to net operating loss carryforwards. The rulings concluded that, for ratemaking purposes, net operating loss carryforwards should be reflected on a separate company basis and should not be reduced by payments received for the utilization of losses by other affiliates under a tax allocation agreement. In 2025, the FERC issued an order reflecting implementation of the rules for the other taxpayer who had a similar fact pattern as Ameren Illinois and ATXI. Accordingly, in the third quarter of 2025, Ameren and Ameren Illinois decreased income tax expense by $48 million and $23 million, respectively, to reflect the revaluation of excess deferred income tax regulatory liabilities resulting from TCJA for FERC-regulated jurisdictions pursuant to IRS guidance and a 2025 FERC order.

LIQUIDITY AND CAPITAL RESOURCES

Collections from our utility tariff-based revenues are our principal source of cash provided by operating activities. A diversified retail customer mix, primarily consisting of rate-regulated residential, commercial, and industrial customers, provides us with a reasonably predictable source of cash. In addition to using cash provided by operating activities, we use available cash, drawings under committed credit agreements, commercial paper issuances, and/or, in the case of Ameren Missouri and Ameren Illinois, short-term affiliate borrowings to support normal operations and temporary capital requirements. We may reduce our short-term borrowings with cash provided by operations or, at our discretion, with long-term borrowings, or, in the case of Ameren Missouri and Ameren Illinois, with capital contributions from Ameren (parent). As of September 30, 2026, there have been no material changes other than in the ordinary course of business related to cash

65

---

Table of Contents

requirements arising from the long-term commitments for fuel for generation, purchased power, and natural gas for distribution as described under Liquidity and Capital Resources in Item 7 of the Form 10-K.

We expect to make significant capital expenditures over the next five years, supported by a combination of long-term debt and equity, as we invest in our electric and natural gas utility infrastructure to support expected increases in demand, overall system reliability, grid modernization, renewable energy target requirements, and other improvements. For additional information about our long-term debt outstanding, including maturities due within one year, and the applicable interest rates, see Note 5 – Long-term Debt and Equity Financings under Part II, Item 8 of the Form 10-K and Note 4 – Long-term Debt and Equity Financings under Part I, Item 1, of this report. As part of its funding plan for capital expenditures, Ameren is using newly-issued shares of common stock to satisfy requirements under the DRPlus and employee benefit plans and expects to continue to do so through at least 2031. Additionally, Ameren may offer and sell from time to time common stock, including under its ATM program, which includes the ability to enter into forward sale agreements, subject to market conditions and other factors. There were no shares issued under the ATM program during the nine months ended September 30, 2026. In August 2026, Ameren increased the amount of common stock available for sale under the ATM program by $2 billion to a total of $5 billion. As of September 30, 2026, Ameren had approximately $2 billion of common stock remaining available for sale under the ATM program. As of September 30, 2026, Ameren had multiple forward sale agreements with various counterparties relating to 19.4 million shares of common stock. In October 2026, Ameren entered into forward sale agreements under the ATM program for 2.1 million shares of common stock. Of these shares, Ameren expects to settle 6.4 million in 2026 and the remaining 15.1 million to fund a portion of its equity needs beyond 2026. Ameren’s equity financing plan is estimated to be approximately $5 billion from 2027 to 2031. This plan includes equity issuances under forward sale agreements, the DRPlus, and employee benefit plans. Ameren expects these issuances to be concentrated primarily near year-end 2027 and year-end 2028 to align with the timing of capital investments and other needs. The Ameren Companies expect their equity to total capitalization and cash flow metrics to support solid investment-grade credit ratings. See Long-term Debt and Equity below and Note 4 – Long-term Debt and Equity Financings under Part I, Item 1, of this report for additional information on the ATM program and forward sale agreements relating to common stock, including those under the ATM program.

The following table presents net cash provided by (used in) operating, investing, and financing activities for the nine months ended September 30, 2026 and 2025:

			Net Cash Provided By Operating Activities																		Net Cash Used In Investing Activities																		Net Cash Provided By Financing Activities
			2026						2025						Variance						2026						2025						Variance						2026						2025						Variance
Ameren			$	2,193		(a)			$	2,397		(a)			$	(204)					$	(4,154)					$	(3,112)					$	(1,042)					$	2,066					$	822					$	1,244
Ameren Missouri			1,282						1,273						9						(2,820)						(1,875)						(945)						1,544						678						866
Ameren Illinois			888			(a)			1,117			(a)			(229)						(1,090)						(1,181)						91						301						92						209

(a)Both Ameren and Ameren Illinois’ cash provided by operating activities included cash outflows of $92 million and $85 million for the electric energy-efficiency rider and $176 million and $40 million for the customer generation rebate program for the nine months ended September 30, 2026 and 2025, respectively.

Cash Flows from Operating Activities

Our cash, cash equivalents, and restricted cash provided by operating activities is affected by fluctuations of trade accounts receivable, inventories, and accounts and wages payable, among other things, as well as the unique regulatory environment for each of our businesses. Substantially all expenditures related to fuel, purchased power, and natural gas purchased for resale are recovered from customers through rate adjustment mechanisms, which may be adjusted without a traditional regulatory rate review, subject to prudence reviews. Similar regulatory mechanisms exist for certain other operating expenses that can also affect the timing of cash provided by operating activities. The timing of cash payments for costs recoverable under our regulatory mechanisms differs from the recovery period of those costs. Additionally, the seasonality of our electric and natural gas businesses, primarily caused by seasonal customer rates and changes in customer demand due to weather, significantly affects the amount and timing of our cash provided by operating activities. For additional information on cash, cash equivalents, and restricted cash, see Note 13 – Supplemental Information under Part I, Item 1, of this report.

Ameren

Ameren’s cash provided by operating activities decreased $204 million in the first nine months of 2026, compared with the year-ago period. The following items contributed to the decrease:

•A $223 million decrease in proceeds received by Ameren Missouri related to production and investment tax credits transferred to unrelated parties.

•A $91 million decrease due to the timing of payments and reimbursements for programs related to customer-owned distributed generation facilities in Ameren Illinois’ service territory.

•A $48 million increase in interest payments, including settlements of interest rate hedges, primarily due to higher average outstanding debt and interest rates on long-term debt.

•A $33 million decrease due to the timing of payments for spent nuclear fuel storage and reimbursements from the DOE.

66

---

Table of Contents

•A $30 million increase in non-nuclear energy center maintenance payments, primarily due to increased reliability measures at the Labadie and Sioux energy centers.

•A $26 million increase in pension and postretirement benefit plan contributions.

•An $18 million decrease due to the timing of receipts and refunds of customer deposits.

•An $18 million increase in payments for materials and supplies at Ameren Illinois to support the operational needs of its electric distribution and transmission businesses.

•A $16 million increase in gross receipts tax payments primarily due to an increase in base rates at Ameren Missouri and Ameren Illinois in 2026, compared to 2025.

•A $14 million increase in fuel oil payments to fill new storage tanks at the Audrain Energy Center. Ameren Missouri is converting the energy center to utilize both natural gas and fuel oil.

•A $13 million increase in payments to Ameren Illinois contractors, primarily related to higher costs to comply with expanded programs under the CEJA.

•An $11 million decrease due to the absence of a property tax refund received in 2025 at Ameren Missouri.

•An $8 million increase in payments to fund mitigation programs ordered in the NSR and Clean Air Act litigation discussed in Note 14 – Commitments and Contingencies under Part II, Item 8, of the Form 10-K.

The following items partially offset the decrease in Ameren’s cash from operating activities between periods:

•A $203 million increase resulting from higher customer collections, primarily from increased electric and natural gas base rates at Ameren Missouri effective June 1, 2025, and September 1, 2025, respectively, pursuant to MoPSC rate orders, electric distribution and transmission base rate increases at Ameren Illinois, and increased natural gas base rates at Ameren Illinois effective December 2, 2025, pursuant to an ICC rate order. These increases were partially offset by lower customer collections under cost recovery mechanisms.

•An $82 million increase due to the timing of payments for accounts payable and prepaid expenses.

•A $24 million decrease in nuclear refueling and maintenance outage payments related to the Callaway Energy Center. The 2026 outage began in late September 2026, while the previous outage was in spring 2025.

Ameren Missouri

Ameren Missouri’s cash provided by operating activities increased $9 million in the first nine months of 2026, compared with the year-ago period. The following items contributed to the increase:

•A $276 million increase resulting from higher customer collections, primarily from increased electric and natural gas base rates effective June 1, 2025, and September 1, 2025, respectively, pursuant to MoPSC rate orders and higher customer collections under cost recovery mechanisms.

•A $77 million increase due to the timing of payments for accounts payable and prepaid expenses.

•A $49 million increase in income tax refunds from Ameren (parent), pursuant to the tax allocation agreement, primarily due to lower taxable income compared to 2025.

•A $24 million decrease in nuclear refueling and maintenance outage payments related to the Callaway Energy Center. The 2026 outage began in late September 2026, while the previous outage was in spring 2025.

The following items partially offset the increase in Ameren Missouri’s cash from operating activities between periods:

•A $223 million decrease in proceeds received related to production and investment tax credits transferred to unrelated parties.

•A $34 million increase in interest payments primarily due to higher average outstanding debt and interest rates on long-term debt.

•A $33 million decrease due to the timing of payments for spent nuclear fuel storage and reimbursements from the DOE.

•A $30 million increase in non-nuclear energy center maintenance payments, primarily due to increased reliability measures at the Labadie and Sioux energy centers.

•A $14 million increase in fuel oil payments to fill new storage tanks at the Audrain Energy Center. Ameren Missouri is converting the energy center to utilize both natural gas and fuel oil.

•An $11 million decrease due to the absence of a property tax refund received in 2025.

•A $10 million increase in pension and postretirement benefit plan contributions.

•A $10 million decrease due to the timing of receipts and refunds of customer deposits.

•A $10 million increase in gross receipts tax payments primarily due to an increase in base rates in 2026, compared to 2025.

•An $8 million increase in payments to fund mitigation programs ordered in the NSR and Clean Air Act litigation discussed in Note 14 – Commitments and Contingencies under Part II, Item 8, of the Form 10-K.

67

---

Table of Contents

Ameren Illinois

Ameren Illinois’ cash provided by operating activities decreased $229 million in the first nine months of 2026, compared with the year-ago period. The following items contributed to the decrease:

•A $91 million decrease due to the timing of payments and reimbursements for programs related to customer-owned distributed generation facilities.

•An $84 million decrease due to lower customer collections under cost recovery mechanisms, partially offset by higher customer collections from electric distribution and transmission base rate increases and increased natural gas base rates effective December 2, 2025, pursuant to an ICC rate order.

•A $25 million increase in interest payments primarily due to higher average outstanding debt and interest rates on long-term debt.

•An $18 million increase in payments for materials and supplies to support the operational needs of its electric distribution and transmission businesses.

•A $13 million increase in income tax payments to Ameren (parent), pursuant to the tax allocation agreement, primarily due to higher taxable income compared to 2025.

•A $13 million increase in payments to contractors, primarily due to higher costs to comply with expanded programs under the CEJA.

•An $11 million increase in pension and postretirement benefit plan contributions.

•A $10 million decrease due to the timing of receipts and refunds of customer deposits.

The decrease in Ameren Illinois’ cash from operating activities between periods was partially offset by a $27 million increase due to the timing of payments for accounts payable and prepaid expenses.

Cash Flows from Investing Activities

Ameren’s cash used in investing activities increased $1,042 million during the first nine months of 2026, compared with the year-ago period, primarily as a result of a $971 million increase in capital expenditures, largely resulting from the acquisition of the Split Rail Solar Project and expenditures on other generation projects at Ameren Missouri and electric distribution infrastructure upgrades at Ameren Illinois, partially offset by decreased major storm-related expenditures at Ameren Missouri and decreased expenditures for natural gas infrastructure upgrades related to timing at Ameren Illinois.

Ameren Missouri’s cash used in investing activities increased $945 million during the first nine months of 2026, compared with the year-ago period, primarily as a result of an $877 million increase in capital expenditures, largely resulting from the acquisition of the Split Rail Solar Project and expenditures on other generation projects, partially offset by decreased storm-related expenditures, and a $43 million increase due to net money pool advances.

Ameren Illinois’ cash used in investing activities decreased $91 million during the first nine months of 2026, compared with the year-ago period, as a result of a $51 million decrease in net money pool advances and a $39 million decrease in capital expenditures, primarily related to decreases in transmission infrastructure upgrades and the timing of natural gas infrastructure upgrades, partially offset by an increase in electric distribution infrastructure upgrades.

68

---

Table of Contents

Capital Expenditures

The following table presents Ameren’s estimate of capital expenditures that will be incurred from 2026 through 2031, including construction expenditures and allowance for funds used during construction. The estimated 2026 to 2030 capital expenditures have significantly increased compared to those estimates disclosed in the Form 10-K, to better align with Ameren Missouri’s 2026 PRP filed in September 2026 and to include a portion of the MISO long-range transmission competitive bid projects awarded to ATXI in 2026.

			2026						2027 - 2031												Total
Ameren Missouri			$	4,000					$	24,650		-			$	27,250					$	28,650		-			$	31,250
Ameren Illinois Electric Distribution			720						3,510			-			3,880						4,230			-			4,600
Ameren Illinois Natural Gas			335						1,785			-			1,975						2,120			-			2,310
Ameren Illinois Transmission			410						2,905			-			3,215						3,315			-			3,625
ATXI and other electric transmission subsidiaries			475						3,310			-			3,675						3,785			-			4,150
Other			5						40			-			45						45			-			50
Ameren			$	5,945					$	36,200		-			$	40,040					$	42,145		-			$	45,985

Ameren Missouri’s estimated capital expenditures include transmission, distribution, grid modernization, and generation-related investments, primarily natural gas, renewable generation, battery energy storage, and fuel cells, consistent with investments outlined in the 2026 PRP through 2031 to maintain reliability and address load growth opportunities based on the 2.8 gigawatts of demand from large load customers under electric service agreements. Ameren Illinois’ estimated capital expenditures are primarily for electric and natural gas transmission and distribution-related investments.

Ameren Missouri continually reviews its generation portfolio and expected power needs, including estimates of future load growth. As a result, Ameren Missouri could modify its plan for generation capacity, the type of generation asset technology that will be employed, and whether capacity or power may be purchased, among other changes. Additionally, we continually review the reliability of our transmission and distribution systems, expected capacity needs, and opportunities for transmission investments within and outside our service territories. The timing and amount of investments could vary because of changes in expected capacity, the condition of transmission and distribution systems, future rate orders, and our ability and willingness to pursue transmission investments, as well as our ability to obtain necessary regulatory approvals, among other factors. Any changes in future generation, transmission, or distribution needs could result in significant changes in capital expenditures or losses, which could be material. Compliance with environmental regulations could also have significant impacts on the level of capital expenditures.

Cash Flows from Financing Activities

Cash provided by, or used in, financing activities is a result of our financing needs, which depend on the level of cash provided by operating activities, the level of cash used in investing activities, the level of dividends, and our long-term debt maturities, among other things.

Ameren’s cash provided by financing activities increased $1.2 billion during the first nine months of 2026, compared with the year-ago period. During the first nine months of 2026, Ameren utilized net proceeds from the issuance of long-term debt of $3.2 billion to repay then-outstanding short-term debt, including short-term debt incurred to refinance $350 million of long-term debt maturities, and for general corporate purposes. Ameren also repaid net short-term debt of $147 million. In comparison, during the first nine months of 2025, Ameren utilized net proceeds from the issuance of long-term debt of $2.0 billion for general corporate purposes, and to repay $300 million of long-term debt maturities and then-outstanding short-term debt. In addition, during the first nine months of 2025, Ameren also repaid net short-term debt of $239 million. During the first nine months of 2026, Ameren paid common stock dividends of $622 million, compared with $576 million in the year-ago period, as a result of an increase in both the dividend rate and the number of common shares outstanding.

Ameren Missouri’s cash provided by financing activities increased $866 million during the first nine months of 2026, compared with the year-ago period. During the first nine months of 2026, Ameren Missouri utilized net proceeds from the issuance of long-term debt of $1.4 billion to repay then-outstanding short-term debt, including net commercial paper of $371 million. Additionally, during the first nine months of 2026, Ameren Missouri utilized capital contributions from Ameren (parent) of $550 million, and cash provided by operating activities to fund, in part, capital expenditures. In comparison, during the first nine months of 2025, Ameren Missouri utilized net proceeds from the issuance of long-term debt of $500 million to repay then-outstanding short-term debt. In addition, during the first nine months of 2025, Ameren Missouri utilized proceeds from net commercial paper issuances of $259 million, money pool borrowings of $51 million, and cash provided by operating activities to fund, in part, capital expenditures. During the first nine months of 2025, Ameren Missouri paid common stock dividends of $125 million.

Ameren Illinois’ cash provided by financing activities increased $209 million during the first nine months of 2026, compared with the year-ago period. During the first nine months of 2026, Ameren Illinois utilized net proceeds from the issuance of long-term debt of $400 million to repay then-outstanding short-term debt. In addition, Ameren Illinois utilized proceeds from net commercial paper issuances of

69

---

Table of Contents

$171 million and cash provided by operating activities to fund, in part, capital expenditures. In comparison, during the first nine months of 2025, Ameren Illinois utilized proceeds from the issuance of long-term debt of $711 million to repay $300 million of long-term debt maturities and then-outstanding short-term debt. Ameren Illinois also repaid net commercial paper borrowings of $88 million and money pool borrowings of $37 million. During the first nine months of 2026, Ameren Illinois also paid common stock dividends of $265 million, compared with $185 million in the year-ago period.

See Long-term Debt and Equity in this section for additional information on maturities and issuances of long-term debt, and issuances of common stock.

Short-term Debt and Liquidity

The following table presents Ameren’s consolidated net available liquidity as of September 30, 2026:

															Available at September 30, 2026
Ameren (parent) and Ameren Missouri:
Missouri Credit Agreement – borrowing capacity															$	1,900
Less: Ameren (parent) commercial paper outstanding															122
Less: Ameren Missouri commercial paper outstanding															100
Less: Letters of credit															30
Missouri Credit Agreement – subtotal															1,648
Ameren (parent) and Ameren Illinois:
Illinois Credit Agreement – borrowing capacity															1,300
Less: Ameren (parent) commercial paper outstanding															86
Less: Ameren Illinois commercial paper outstanding															188
Less: Letters of credit															4
Illinois Credit Agreement – subtotal															1,022
Subtotal															$	2,670
Add: Cash and cash equivalents															40
Net Available Liquidity(a)															$	2,710

(a)Does not include Ameren’s forward equity sale agreements. See Note 4 – Long-term Debt and Equity Financings under Part I, Item 1, of this report for additional information.

The Credit Agreements, among other things, provide $3.2 billion of credit until maturity in December 2030. See Note 3 – Short-term Debt and Liquidity under Part I, Item 1, of this report for additional information on the Credit Agreements. Borrowings under the Credit Agreements and commercial paper issuances are based upon available interest rates at the time of the borrowing or issuance.

Ameren has a money pool agreement with and among its utility subsidiaries to coordinate and to provide for certain short-term cash and working capital requirements. As short-term capital needs arise, and based on availability of funding sources, Ameren Missouri and Ameren Illinois will access funds from the utility money pool, the Credit Agreements, or the commercial paper programs depending on which option has the lowest interest rates.

See Note 3 – Short-term Debt and Liquidity under Part I, Item 1, of this report for additional information on credit agreements, commercial paper issuances, Ameren’s money pool agreements and related borrowings, and relevant interest rates.

The issuance of short-term debt securities by Ameren’s utility subsidiaries is subject to FERC approval under the Federal Power Act. In January 2025, the FERC issued orders authorizing ATXI to issue up to $500 million of short-term debt securities through January 2027. In December 2025, the FERC issued orders authorizing Ameren Missouri and Ameren Illinois to issue up to $1.6 billion and $1.1 billion, respectively, of short-term debt securities through December 2027.

The Ameren Companies continually evaluate the adequacy and appropriateness of their liquidity arrangements for changing business conditions. When business conditions warrant, changes may be made to the existing Credit Agreements or to other borrowing arrangements, or other arrangements may be made.

70

---

Table of Contents

Long-term Debt and Equity

The following table presents issuances (net of any issuance premiums or discounts) of long-term debt and equity, as well as redemptions and maturities of long-term debt for the nine months ended September 30, 2026 and 2025:

			Month Issued, Redeemed, or Matured						2026						2025
Issuances of Long-term Debt
Ameren:
5.375% Senior unsecured notes due 2035			March						$	—					$	749
5.00% Senior unsecured notes due 2036			March						399						—
Junior subordinated notes due 2057(a)			September						900						—
Ameren Missouri:
4.80% First mortgage bonds due 2036			February						450						—
5.55% First mortgage bonds due 2056			February						448						—
5.25% First mortgage bonds due 2035			April						—						500
5.75% First mortgage bonds due 2056			June						497						—
Ameren Illinois:
5.625% First mortgage bonds due 2055			March						—						350
5.50% First mortgage bonds due 2036			August						400
5.625% First mortgage bonds due 2055			September						—						361
ATXI:
5.83% Senior unsecured notes due 2041			August						140						—
Total Ameren long-term debt issuances									$	3,234					$	1,960
Issuances of Common Stock
Ameren:
DRPlus and 401(k)(b)(c)			Various						$	31					$	35
Total Ameren common stock issuances(d)									$	31					$	35
Maturities of Long-term Debt
Ameren:
3.65% Senior unsecured notes due 2026			February						$	350					$	—
Ameren Missouri:
4.85% Securitized utility tariff bonds due 2039(e)			April						12						—
Ameren Illinois:
3.25% Senior secured notes due 2025			March						—						300
Total Ameren long-term debt maturities									$	362		(f)			$	300		(f)

(a)The junior subordinated notes will pay interest at a fixed annual rate of 6.45% until March 15, 2032. After that date, the interest rate will be reset every five years to the applicable five-year United States Treasury rate plus 1.868%, subject to a minimum rate of 6.45%.

(b)Ameren issued a total of 0.3 million and 0.3 million shares of common stock under its DRPlus and 401(k) plan for the nine months ended September 30, 2026 and 2025, respectively.

(c)Excludes a $6 million and $7 million receivable at September 30, 2026 and 2025, respectively.

(d)Excludes 0.2 million and 0.3 million shares of common stock valued at $25 million and $25 million issued for no cash consideration in connection with stock-based compensation for the nine months ended September 30, 2026 and 2025, respectively.

(e)These securitized utility tariff bonds were issued by AMF. The securitized tariff bondholders have no recourse to Ameren Missouri.

(f)Excludes Ameren (parent)’s purchases of senior secured notes and first mortgage bonds issued by Ameren Missouri and first mortgage bonds issued by Ameren Illinois for $16 million and $24 million in aggregate for the nine months ended September 30, 2026 and 2025, respectively.

See Note 4 – Long-term Debt and Equity Financings under Part I, Item 1, of this report for additional information, including proceeds from issuances of long-term debt, the use of those proceeds, Ameren’s forward equity sale agreements, and the ATM program.

Indebtedness Provisions and Other Covenants

At September 30, 2026, the Ameren Companies were in compliance with the provisions and covenants contained in their credit agreements, indentures, and articles of incorporation, as applicable, and ATXI was in compliance with the provisions and covenants contained in its note purchase agreements. See Note 3 – Short-term Debt and Liquidity under Part I, Item 1, of this report and Note 4 – Short-term Debt and Liquidity and Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10-K for a discussion of provisions, applicable cross-default provisions, and covenants contained in our credit agreements, in ATXI’s note purchase agreements, and in certain of the Ameren Companies’ indentures and articles of incorporation.

71

---

Table of Contents

We consider access to short-term and long-term capital and credit markets to be a significant source of funding for capital requirements not satisfied by cash provided by our operating activities. Inability to raise capital on reasonable terms, particularly during times of uncertainty in the capital and credit markets, could negatively affect our ability to maintain and expand our businesses. After assessing their respective current operating performance, liquidity, and credit ratings (see Credit Ratings below), Ameren, Ameren Missouri, and Ameren Illinois each believes that it will continue to have access to the capital and credit markets on reasonable terms. However, events beyond Ameren’s, Ameren Missouri’s, and Ameren Illinois’ control may create uncertainty in the capital and credit markets or make access to the capital and credit markets uncertain or limited. Such events could increase our cost of capital and adversely affect our ability to access the capital and credit markets.

Dividends

The amount and timing of dividends payable on Ameren’s common stock are within the sole discretion of Ameren’s board of directors. Ameren’s board of directors has not set specific targets or payout parameters when declaring common stock dividends, but it considers various factors, including Ameren’s overall payout ratio, payout ratios of our peers, projected cash flow and potential future cash flow requirements, historical earnings and cash flow, projected earnings, impacts of regulatory orders or legislation, and other key business considerations. Ameren expects its dividend payout ratio to be between 45% and 55% of annual earnings over the next few years.

See Note 4 – Short-term Debt and Liquidity and Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10-K for additional discussion of covenants and provisions contained in certain of the Ameren Companies’ financial agreements and articles of incorporation that would restrict the Ameren Companies’ payment of dividends in certain circumstances. At September 30, 2026, none of these circumstances existed at Ameren, Ameren Missouri, or Ameren Illinois and, as a result, these companies were not restricted from paying dividends.

The following table presents common stock dividends declared and paid by Ameren Corporation to its common shareholders and by Ameren subsidiaries to their parent, Ameren Corporation, for the nine months ended September 30, 2026 and 2025:

			Nine Months
			2026						2025
Ameren			$	622					$	576
Ameren Missouri			—						125
Ameren Illinois			265						185
ATXI			40						49

Collateral Postings

Any weakening of our credit ratings may reduce access to capital and trigger additional collateral postings and prepayments. Such changes may also increase the cost of borrowing, resulting in an adverse effect on earnings. Cash collateral postings and prepayments made with external parties were $70 million for Ameren and Ameren Missouri and cash collateral posted by external parties was $154 million, $67 million, and $87 million for Ameren, Ameren Missouri, and Ameren Illinois at September 30, 2026. A sub-investment-grade issuer or senior unsecured debt rating (below “Baa3” from Moody’s or below “BBB-” from S&P) at September 30, 2026, could have resulted in Ameren, Ameren Missouri, or Ameren Illinois being required to post additional collateral or other assurances for certain trade and contractual obligations amounting to $120 million, $54 million, and $66 million, respectively.

Changes in commodity prices could trigger additional collateral postings and prepayments. Based on credit ratings at September 30, 2026, if market prices were 15% higher or lower than September 30, 2026 levels in the next 12 months and 20% higher or lower thereafter through the end of the term of the commodity contracts, then Ameren and Ameren Missouri could be required to post $47 million of collateral or provide other assurances for certain trade and contractual obligations.

OUTLOOK

Below are some key trends, events, and uncertainties that may reasonably affect our results of operations, financial condition, or liquidity, as well as our ability to achieve strategic and financial objectives, for 2026 and beyond. For additional information regarding recent rate orders, lawsuits, and pending requests filed with state and federal regulatory commissions, including those discussed below, see Note 2 – Rate and Regulatory Matters under Part I, Item 1, of this report and Note 2 – Rate and Regulatory Matters under Part II, Item 8, of the Form 10-K.

Operations

•The PPRA became effective in 2025. The law made modifications to integrated resource planning, which requires Missouri electric utilities to file plans for meeting their customers' long-term energy needs. By August 2027, the MoPSC will publish a schedule for

72

---

Table of Contents

Missouri electric utilities to file integrated resource plans every four years. The MoPSC will be required to issue an order on the plans and shall determine whether the electric utility has submitted sufficient documentation and selected preferred resource plans representing a reasonable and prudent means of serving the utility's load obligations at just and reasonable rates. If the MoPSC approves the plans, requests for CCNs for new generation facilities to be constructed or acquired as a part of the approved plans shall be deemed necessary and convenient and the scope of the CCN proceedings to review projects will be limited. The approved generation facilities will also be eligible to include construction work in progress in rate base, subject to MoPSC approval, which would improve the timeliness of cash recovery. Utilities are not allowed to capitalize allowance for funds used during construction on amounts included in rate base under this provision. The amount of construction work in progress to be included in rate base is limited to prudently incurred expenditures made within the construction period for the facility. Separately, outside of the integrated resource planning process discussed above, the law allows a Missouri electric utility to request that the MoPSC authorize the inclusion of construction work in progress for new natural gas-fired generation facilities in rate base, subject to the same restrictions discussed above. The provisions allowing for the inclusion of construction work in progress on natural gas-fired generation in rate base expire in December 2035, unless Ameren Missouri requests and receives MoPSC approval of an extension through 2045. Also, the law allows natural gas utilities to file regulatory rate reviews using a future test year, subject to MoPSC approval. The law also made modifications to the PISA and requires electric utilities to submit service tariff schedules for certain large load customers as discussed below.

•The PISA permits Ameren Missouri to defer and recover 85% of the depreciation expense for investments in qualifying property, plant, and equipment placed in service and not included in base rates. Investments not eligible for recovery under the PISA include amounts related to new nuclear generation facilities and service to new customer premises. Additionally, the PISA permits Ameren Missouri to earn a return at the applicable WACC on 85% of rate base that incorporates those qualifying investments, as well as changes in total accumulated depreciation excluding retirements and plant-related deferred income taxes since the previous regulatory rate review. Also, under the RESRAM, Ameren Missouri is permitted to recover the 15% of depreciation expense not recovered under the PISA, and earn a return at the applicable WACC for investments in renewable generation plant placed in service to comply with Missouri’s renewable energy standard. The PISA and the RESRAM mitigate the effects of regulatory lag between regulatory rate reviews. Those investments not eligible for recovery under the PISA and the remaining 15% of certain property, plant, and equipment placed in service, unless eligible for recovery under the RESRAM, remain subject to regulatory lag. Pursuant to the PPRA discussed above, Ameren Missouri’s PISA election was extended through 2035 and an additional extension through 2040 is allowed if requested by Ameren Missouri and approved by the MoPSC. This law also reduced the annual limit on increases to the electric service revenue requirement used to set customer rates, compared to the revenue requirement established in the immediately preceding rate order, due to the inclusion of incremental PISA deferrals in the revenue requirement. The annual limit in effect was 2.5% and changed to 2.25%, prorated monthly, for revenue requirements approved by the MoPSC after August 2025. Ameren Missouri expects significantly higher allowance for equity funds used during construction and investments in infrastructure eligible for PISA in 2026, compared to 2025, and in 2027, compared to 2026.

•In June 2026, Ameren Missouri filed a request with the MoPSC seeking approval to increase its annual revenues for electric service by $343 million. The MoPSC proceeding relating to the proposed electric service rate changes will take place over a period of up to 11 months, with a decision by the MoPSC expected by May 2027 and new rates effective by June 2027. Ameren Missouri cannot predict the level of any electric service rate change the MoPSC may approve, whether the requested regulatory recovery mechanisms will be continued, or whether any rate change that may eventually be approved will be sufficient for Ameren Missouri to recover its costs and earn a reasonable return on its investments when the rate change goes into effect.

•Ameren Illinois and ATXI use a forward-looking rate calculation with an annual revenue requirement reconciliation for each company’s electric transmission business. Based on expected rate base and the currently allowed 10.48% ROE, which includes a 50-basis-point incentive adder for participation in an RTO, the revenue requirements that will be included in 2027 rates for Ameren Illinois’ and ATXI’s electric transmission businesses are $749 million and $319 million, respectively. These revenue requirements represent increases in Ameren Illinois’ and ATXI’s revenue requirements of $64 million and $53 million, respectively, from the revenue requirements reflected in 2026 rates, primarily due to higher expected rate base. These rates will affect Ameren Illinois’ and ATXI’s cash receipts during 2027, but do not determine their respective electric transmission service operating revenues, which instead are based on 2027 actual recoverable costs, rate base, and a return on rate base at the applicable WACC as calculated under the FERC formula ratemaking framework.

•In 2020, the FERC issued a Notice of Proposed Rulemaking on its transmission incentives policy, which proposed to increase the incentive ROE for participation in an RTO to 100 basis points from the current 50 basis points and revised the parameters for awarding incentives, while limiting the overall incentives to a cap of 250 basis points, among other things. In 2021, the FERC issued a Supplemental Notice of Proposed Rulemaking, which proposed to modify the Notice of Proposed Rulemaking’s incentive for participation in an RTO by limiting this incentive for utilities that join an RTO to 50 basis points and only allowing them to earn the incentive for three years, among other things. If this proposal is included in a final rule, Ameren Illinois and ATXI would no longer be eligible for the 50 basis point RTO incentive adder, prospectively. The FERC is under no deadline to issue a final rule on this matter. Ameren is unable to predict the ultimate impact of any changes to the FERC’s incentives policy. A 50-basis-point change in the FERC-allowed ROE would affect Ameren’s and Ameren Illinois’ annual net income by an estimated $19 million and $14 million, respectively,

73

---

Table of Contents

based on each company’s 2026 projected rate base.

•Pursuant to the CEJA, Ameren Illinois may file an MYRP with the ICC to establish base rates for electric distribution service to be charged to customers for each calendar year of a four-year period. The base rates for a particular calendar year are based on forecasted recoverable costs and an ICC-determined ROE applied to Ameren Illinois’ forecasted average annual rate base using a forecasted capital structure, with a common equity ratio of up to 50% being deemed prudent and reasonable by law and a higher equity ratio requiring specific ICC approval. The ROE determined by the ICC for each calendar year of the four-year period is subject to annual adjustments based on certain performance incentives and penalties. An MYRP allows Ameren Illinois to reconcile electric distribution service rates to its actual revenue requirement on an annual basis, subject to a reconciliation cap and adjustments to the ROE. Under the MYRP discussed below, Ameren Illinois’ 2026 electric distribution service revenues are based on its 2026 actual recoverable costs, 2026 year-end rate base, and an ROE of 8.72%, as adjusted for any performance incentives or penalties, provided the actual revenue requirement does not exceed the reconciliation cap. If a given year’s revenue amount collected from customers varies from the approved revenue requirement, an adjustment is made to electric operating revenues with an offset to a regulatory asset or liability to reflect that year’s actual revenue requirement. The regulatory balance is then collected from, or refunded to, customers within two years from the end of the applicable annual period. Additionally, the RBA ensures electric distribution service revenues are decoupled from sales volumes and wholesale and miscellaneous revenue differences from those assumed in the revenue requirement approved by the ICC. The RBA remains effective whether Ameren Illinois elects to file an MYRP or a traditional regulatory rate review. In April 2026, Ameren Illinois filed a reconciliation adjustment to its 2025 electric distribution service revenue requirement with the ICC. In August 2026, Ameren Illinois updated its reconciliation adjustment, requesting recovery of $28 million. The adjustment reflects Ameren Illinois’ actual 2025 recoverable costs, 2025 year-end rate base, and a capital structure composed of 50% common equity. An ICC decision is required by December 2026, and any approved adjustment would be collected from customers in 2027.

•In December 2024, the ICC issued an order in connection with a revised Grid Plan and a revised MYRP filed by Ameren Illinois in March 2024, approving revenue requirements for electric distribution services for 2024 through 2027 of $1,206 million, $1,287 million, $1,367 million, and $1,421 million, respectively. Using the 2023 revenue requirement as a starting point, the approved revenue requirements in the ICC’s December 2024 order represent a cumulative four-year increase of $308 million.

•In January 2026, the CRGA was enacted and became effective in June 2026. The law includes certain provisions that affect Ameren Illinois’ annual investments in energy-efficiency programs, and the related return on those investments. Under the law, the annual spending cap for energy-efficiency investments increased for 2027, 2028, and 2029. As a result, in May 2026, Ameren Illinois filed an electric energy efficiency plan with the ICC, which includes annual investments in electric energy-efficiency programs up to $192 million, $239 million, and $276 million for 2027, 2028, and 2029, respectively. A decision by the ICC in this proceeding is expected in November 2026. In addition, Ameren Illinois expects the ROE component of the applicable WACC used to calculate its return on energy-efficiency investments for the year to change in 2027 to that year’s ICC-approved ROE for Ameren Illinois’ electric distribution service. The ROE will continue to be increased or decreased based on the achievement of certain goals as discussed below. For 2027, the allowed ROE will be the ICC-approved 8.72% from Ameren Illinois’ MYRP electric distribution service regulatory rate review.

•Pursuant to Illinois law, Ameren Illinois’ electric energy-efficiency investments are deferred as a regulatory asset and earn a return at the applicable WACC. Ameren Illinois expects the ROE component of the applicable WACC to be based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points through 2026. The allowed ROE on electric energy-efficiency investments can be increased or decreased by up to 200 basis points, depending on the achievement of annual energy savings and demand goals. While the ICC has approved a plan for Ameren Illinois to invest approximately $126 million per year in electric energy-efficiency programs through 2029, the ICC has the ability to reduce the amount of electric energy-efficiency savings goals in future program years if there are insufficient cost-effective programs available, which could reduce Ameren Illinois’ investments in electric energy-efficiency programs. Pursuant to the CRGA, Ameren Illinois filed an updated energy-efficiency plan for 2027 through 2029 as discussed above.

•In November 2025, the ICC issued an order in Ameren Illinois’ January 2025 natural gas delivery service regulatory rate review, which resulted in an increase to Ameren Illinois’ annual revenues for natural gas delivery service of $79 million. The order reflected a reduction of $75 million of planned distribution and transmission capital investments included in Ameren Illinois’ future test year request. The new rates became effective in December 2025. In January 2026, Ameren Illinois filed an appeal of the ICC’s November 2025 order to the Illinois Appellate Court for the Fifth Judicial District. The appeal challenged the inclusion of the non-service cost component of the net periodic benefit income related to other postretirement benefits in the annual revenue requirement and the $75 million reduction of planned capital investments, among other things. The court is under no deadline to address the appeal, and Ameren Illinois cannot predict the ultimate outcome of the appeal.

•A November 2023 ICC order directed the ICC staff to develop a plan for a future of gas proceeding. All of the Illinois natural gas utilities subject to ICC regulation are included in this proceeding, which is exploring issues involving the decarbonization of the natural gas distribution system in light of the state of Illinois’ goal of economy-wide 100% clean energy by 2050, pursuant to the CEJA. Some of the

74

---

Table of Contents

issues being addressed include the mitigation of any natural gas distribution stranded assets, the role of energy efficiency in decarbonization, and the associated impacts of natural gas decarbonization to the electric distribution system, among others. A final ICC staff report is expected in 2026 and will be used by the ICC to guide further action, if any.

•Ameren Missouri’s scheduled refueling and maintenance outage at its Callaway Energy Center began in late September 2026, and the energy center is expected to return to service in November 2026. The next refueling and maintenance outage is scheduled for the spring of 2028. During a scheduled refueling, which occurs every 18 months, maintenance expenses are deferred as a regulatory asset and amortized until the completion of the next refueling and maintenance outage. During an outage, depending on the availability of its other generation sources and the market prices for power, Ameren Missouri’s purchased power costs may increase and the amount of excess power available for sale may decrease versus non-outage years. Changes in purchased power costs and excess power available for sale are included in the FAC, which results in limited impacts to earnings. In addition, Ameren Missouri may incur increased non-nuclear energy center maintenance costs in non-outage years.

•Ameren Missouri and Ameren Illinois continue to make infrastructure investments to meet customer needs and expect to seek increases to electric and natural gas rates to recover the cost of investments and earn an adequate return. Ameren Missouri and Ameren Illinois will also seek new, or maintain existing, regulatory and legislative solutions to address regulatory lag and to support investment in their utility infrastructure for the benefit of their customers. Ameren Missouri and Ameren Illinois continue to face cost recovery pressures, higher cost of debt, customer conservation efforts, the impacts of additional customer energy-efficiency programs, and increased customer use of increasingly cost-effective advancements in innovative energy technologies, including private generation and battery energy storage. We expect a net increase in demand resulting from the electrification of the economy, including in the transportation sector. In addition, several entities in various industries are considering either locating or expanding their operations within our service territories. In 2026, Ameren Missouri executed electric service agreements with large load customers under its modified large primary service tariff that was approved in 2025, representing 2.8 gigawatts of demand that is expected to begin materializing in the second half of 2027 and to reach full capacity in 2030. Construction agreements have been signed with developers representing an additional 1.2 gigawatts of demand that has not been secured through electric service agreements. Serving increased demand due to electrification, new customers, and other growth will require increased investments, including future investments for system reliability improvements and new generation sources, which will result in rate base growth, and higher purchased power costs in the future until new generation is placed in service. Ameren Missouri’s purchased power costs are part of the net energy costs recoverable under the FAC, with 95% of the variance between net energy costs and the amount set in base rates recovered or refunded through the FAC.

Liquidity and Capital Resources

•As discussed above, Ameren Missouri has executed electric service agreements with large load customers in 2026, and several other entities in various industries are considering either locating or expanding their operations within Ameren Missouri’s service territory. In order to address these load growth opportunities and maintain reliability, Ameren Missouri filed its preferred resource plan with the MoPSC in September 2026. Ameren’s ambition is to achieve net-zero carbon emissions by 2045; however, it will no longer maintain interim emissions-reduction goals. Achieving net-zero carbon emissions will be dependent on a variety of factors, including cost-effective advancements in innovative energy and carbon-capture technologies and constructive federal and state energy and economic policies. The 2026 PRP includes, among other things, the following:

•estimated total load growth of 2.9 gigawatts by 2030, 5 gigawatts by 2035, and 6 gigawatts by 2045;

•adding 2,100 MWs of natural gas-fired combined-cycle generation by 2031, which are expected to be achieved through the West Alton Natural Gas Project discussed in Note 2 – Rate and Regulatory Matters under Part I, Item 1, of this report, an additional 2,800 MWs by 2035, and an additional 1,400 MWs by 2042;

•adding 1,900 MWs of natural gas-fired simple-cycle generation by 2029, which includes the Big Hollow and Castle Bluff natural gas generation projects discussed in Note 2 – Rate and Regulatory Matters under Part I, Item 1, of this report, and an additional 2,400 MWs by 2045;

•adding 500 MWs of natural gas fuel cells by 2030;

•adding 1,300 MWs of solar generation by 2030, which includes the Reform, Tom Sawyer, and Ringer solar generation projects discussed in Note 2 – Rate and Regulatory Matters under Part I, Item 1, of this report, an additional 1,050 MWs by 2035, and an additional 1,250 MWs by 2045;

•adding 1,500 MWs of wind generation by 2040;

•adding 2,400 MWs of battery energy storage by 2030, which includes the battery energy storage projects discussed in Note 2 – Rate and Regulatory Matters under Part I, Item 1, of this report;

•adding 1,200 MWs of nuclear generation by 2040;

•retiring all of Ameren Missouri’s coal-fired energy centers by 2042;

•retiring 1,800 MWs of Ameren Missouri’s natural gas-fired energy centers by 2040 to comply with Illinois law;

•the continued implementation of customer energy-efficiency and demand response programs; and

75

---

Table of Contents

•the expectation that Ameren Missouri will seek and receive NRC approval for an extension of the operating license for the Callaway Energy Center beyond its current 2044 expiration date.

Ameren Missouri’s plan could be affected by, among other factors: Ameren Missouri’s ability to obtain CCNs from the MoPSC, and any other required state or federal approvals for the addition of renewable resources, battery energy storage, nuclear or natural gas-fired generation, or natural gas fuel cells, retirement of energy centers, and new or continued customer energy-efficiency programs; the ability to enter into agreements for renewable, natural gas-fired, or nuclear generation, natural gas fuel cells, or battery energy storage and acquire or construct those resources at a reasonable cost; the ability of suppliers, contractors, and developers to meet contractual commitments and complete projects timely, which is dependent upon the availability of necessary labor, materials, and equipment, geopolitical conflict, or government actions, among other things; changes in the scope and timing of projects; the ability to enter into natural gas supply agreements at reasonable prices and adequate quantities to power Ameren Missouri’s natural gas-fired energy centers; the continued existence and ability to qualify for, and use or transfer, federal production or investment tax credits; the ability to maintain system reliability; new and/or changes in environmental regulations, including those related to CO2 and other greenhouse gas emissions; energy and capacity prices; and demand; Ameren Missouri’s ability to obtain necessary rights-of-way, easements, and transmission interconnection agreements at an acceptable cost and in a timely fashion; the ability to earn an adequate return on invested capital; and the ability to raise capital on reasonable terms. Also, changes to capacity accreditation rules adopted by the MISO could reduce the accredited capacity of renewable generation and battery energy storage and increase regional capacity prices, potentially requiring additional investment and higher costs to satisfy resource adequacy requirements. In addition, recent changes in federal domestic energy policy, including low cost financing programs for certain fossil fuel-fired generation projects, have reflected increased investment in fossil fuel infrastructure. This change could impact Ameren Missouri’s ability to construct and/or acquire renewable energy generation facilities and battery energy storage. Ameren Missouri expects to file its next preferred resource plan in September 2029.

•Through 2031, we expect to make significant capital expenditures to improve our electric and natural gas utility infrastructure, with a major portion directed to our transmission and distribution systems, as well as generation and battery energy storage facilities, consistent with investments outlined in the 2026 PRP discussed above to maintain reliability and address load growth opportunities based on the 2.8 gigawatts of demand from large load customers under electric service agreements. We estimate that we will invest up to $46.0 billion (Ameren Missouri – up to $31.3 billion; Ameren Illinois – up to $10.5 billion; ATXI – up to $4.2 billion) of capital expenditures from 2026 through 2031. These estimates include the first tranche MISO long-range transmission projects assigned to Ameren, the first tranche competitive projects awarded to ATXI, a portion of the second tranche projects assigned to Ameren, and a portion of the second tranche competitive projects awarded to ATXI, all of which are discussed below.

•In 2021, the MISO issued a report outlining a preliminary long-range transmission planning roadmap of projects through 2039, which considers the rapidly changing generation mix within MISO resulting from significant additions of renewable generation, actual and expected generation plant closures, and state mandates or goals for clean energy or carbon emissions reductions. In 2022, the MISO approved the first tranche of projects under the roadmap. A portion of these projects were assigned to various utilities, of which Ameren was awarded projects that are estimated to cost approximately $1.8 billion, based on the MISO’s cost estimate. Related to these projects, Ameren began construction in 2024, with forecasted completion dates near the end of this decade. In addition, the MISO awarded three competitive bid projects to ATXI and another owner that represent a total estimated investment of approximately $250 million for ATXI. Also in 2024, the MISO approved a first set of second tranche projects. A portion of these projects were assigned to Ameren and are estimated to cost approximately $1.3 billion, based on the MISO’s cost estimate. Related to these projects, Ameren expects to begin construction in mid-2028, with forecasted completion dates early in the next decade. The first set of second tranche projects also includes competitive bid projects. In 2026, the MISO awarded three of these competitive bid projects to ATXI and other joint owners that represent a total estimated investment of approximately $1.2 billion for ATXI, based on the MISO’s cost estimate. In August 2026, the FERC approved transmission rate incentives relating to two of these competitive bid projects. The incentives will allow construction work in progress to be included in rate base, thereby improving the timeliness of cash recovery, and will allow recovery of prudently incurred costs, subject to FERC approval, for any portion of the projects if they are abandoned for reasons beyond the control of ATXI. Since construction work in progress will be included in rate base and earn a return, ATXI will not capitalize allowance for funds used during construction on these projects.

•In 2025, the presidential administration issued several executive orders on environmental regulations and enforcement. Many of these actions require further implementation by the EPA, and some of these actions will likely be subject to further judicial review. Grid reliability, environmental, or other regulations, including those related to CO2 or other emissions, or other executive orders or actions taken by federal or state regulators, including federal orders related to planned retirements of coal-fired power plants, could result in significant changes in capital expenditures and operating costs. Regulations can be reviewed and repealed, and replacement or alternative regulations can be proposed or adopted by the regulatory agencies, including the EPA. See Note 9 – Commitments and Contingencies under Part I, Item 1, of this report, for additional information on environmental matters. The ultimate implementation of any of these new regulations, as well as the timing of any such implementation, is uncertain. Ameren Missouri’s operating costs and capital expenditures are subject to MoPSC prudence reviews, which could result in cost disallowances, as well as regulatory lag. The

76

---

Table of Contents

cost of Ameren Illinois’ purchased power and natural gas purchased for resale could increase. However, Ameren Illinois expects that these costs would be recovered from customers with no material adverse effect on its results of operations, financial position, or liquidity. Ameren’s and Ameren Missouri’s earnings could benefit from increased investment to comply with environmental regulations if those investments are reflected and recovered on a timely basis in customer rates.

•The Ameren Companies have multiyear credit agreements that cumulatively provide $3.2 billion of credit through December 2030, subject to a 364-day repayment term for Ameren Missouri and Ameren Illinois, with the option to seek incremental commitments to increase the cumulative credit provided to $4.0 billion. See Note 3 – Short-term Debt and Liquidity under Part I, Item 1, of this report and Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of the Form 10-K for additional information regarding the Credit Agreements. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10-K for long-term debt maturities from 2026 to 2031 and beyond at Ameren (parent), Ameren Missouri, Ameren Illinois, and ATXI. See Note 4 – Long-term Debt and Equity Financings under Part I, Item 1, of this report for outstanding forward sale agreements, including under the ATM program, and issuances and maturities of long-term debt in 2026 through the date of this report. Ameren (parent) entered into interest rate swaps to hedge interest rate risk on certain forecasted interest payments associated with debt issuances in 2026 and 2027. The use of cash provided by operating activities and short-term borrowings to fund capital expenditures and other long-term investments at the Ameren Companies frequently results in a working capital deficit, defined as current liabilities exceeding current assets, as was the case at September 30, 2026, for Ameren. Ameren, Ameren Missouri, and Ameren Illinois each believe that their liquidity is adequate given their respective expected operating cash flows, capital expenditures, and financing plans, and expect to continue to have access to the capital and credit markets on reasonable terms when needed. However, there can be no assurance that significant changes in economic conditions, disruptions in the capital and credit markets, or other unforeseen events will not materially affect their ability to execute their expected operating, capital, or financing plans.

•Ameren expects its cash used for currently planned capital expenditures and dividends to exceed cash provided by operating activities over the next several years. As part of its funding plan for capital expenditures, Ameren is using newly-issued shares of common stock to satisfy requirements under the DRPlus and employee benefit plans and expects to continue to do so through at least 2031. Additionally, Ameren may offer and sell from time to time common stock, including under its ATM program, which includes the ability to enter into forward sale agreements, subject to market conditions and other factors. In August 2026, Ameren increased the amount of common stock available for sale under the ATM program by $2 billion to a total of $5 billion. As of September 30, 2026, Ameren had approximately $2 billion of common stock remaining available for sale under the ATM program. As of September 30, 2026, Ameren had multiple forward sale agreements with various counterparties relating to 19.4 million shares of common stock. In October 2026, Ameren entered into forward sale agreements under the ATM program for 2.1 million shares of common stock. Of these shares, Ameren expects to settle 6.4 million in 2026 and the remaining 15.1 million to fund a portion of its equity needs beyond 2026. Ameren’s equity financing plan is estimated to be approximately $5 billion from 2027 to 2031. This plan includes equity issuances under forward sale agreements, the DRPlus, and employee benefit plans. Ameren expects these issuances to be concentrated primarily near year-end 2027 and year-end 2028 to align with the timing of capital investments and other needs. The Ameren Companies expect their equity to total capitalization and cash flow metrics to support solid investment-grade credit ratings. Ameren Missouri and Ameren Illinois expect to fund cash flow needs through debt issuances, cash provided by operating activities, and/or capital contributions from Ameren (parent).

•Pursuant to the IRA and the OBBBA, Ameren Missouri expects to transfer production and investment tax credits to unrelated parties in an aggregate amount of approximately $2.9 billion from 2026 to 2031. Proceeds from these transfers are included in Ameren Missouri’s tracker related to production and investment tax credits allowed under the IRA and the OBBBA or the RESRAM and are ultimately refunded to customers.

•As of September 30, 2026, Ameren had $339 million in tax benefits from federal and state income tax credit carryforwards, $115 million in tax benefits from federal and state net operating loss carryforwards, $20 million in tax receivables, which will be utilized in future periods, and $47 million in receivables related to production and investment tax credits to be transferred to third parties. Future expected income tax payments are based on expected taxable income, available income tax credit and net operating loss carryforwards, and current tax law. Expected taxable income is affected by expected capital expenditures, when property, plant, and equipment is placed in-service or retired, and the timing of regulatory reviews, among other things. Ameren expects annual federal income tax payments to be immaterial through 2031.

The above items could have a material impact on our results of operations, financial position, and liquidity. Additionally, in the ordinary course of business, we evaluate strategies to enhance our results of operations, financial position, and liquidity. These strategies may include acquisitions, divestitures, opportunities to reduce costs or increase revenues, and other strategic initiatives to increase Ameren’s shareholder value. We are unable to predict which, if any, of these initiatives will be executed. The execution of these initiatives may have a material impact on our future results of operations, financial position, or liquidity.

77

---

Table of Contents

REGULATORY MATTERS

See Note 2 – Rate and Regulatory Matters under Part I, Item 1, of this report.

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK.

There have been no material changes to the quantitative and qualitative disclosures about interest rate risk, credit risk, commodity price risk, investment price risk, and commodity supplier risk included in the Form 10-K. See Item 7A under Part II of the Form 10-K for a more detailed discussion of our market risk.

ITEM 4. CONTROLS AND PROCEDURES.

(a)Evaluation of Disclosure Controls and Procedures

As of September 30, 2026, evaluations were performed under the supervision and with the participation of management, including the principal executive officer and the principal financial officer of each of the Ameren Companies, of the effectiveness of the design and operation of such registrant’s disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) of the Exchange Act). Based on those evaluations, as of September 30, 2026, the principal executive officer and the principal financial officer of each of the Ameren Companies concluded that such disclosure controls and procedures are effective to provide reasonable assurance that information required to be disclosed in such registrant’s reports filed or submitted under the Exchange Act is recorded, processed, summarized, and reported within the time periods specified in the SEC’s rules and forms and such information is accumulated and communicated to its management, including its principal executive officer and its principal financial officer, to allow timely decisions regarding required disclosure.

(b)Changes in Internal Controls over Financial Reporting

There has been no change in any of the Ameren Companies’ internal control over financial reporting during their most recent fiscal quarter that has materially affected, or is reasonably likely to materially affect, each of their internal control over financial reporting.

PART II. OTHER INFORMATION

ITEM 1. LEGAL PROCEEDINGS.

We are involved in legal and administrative proceedings before various courts and agencies with respect to matters that arise in the ordinary course of business, some of which involve substantial amounts of money. We believe that the final disposition of these proceedings, except as otherwise disclosed in this report, will not have a material adverse effect on our results of operations, financial position, or liquidity. Risk of loss is mitigated, in some cases, by insurance or contractual or statutory indemnification. We believe that we have established appropriate reserves for potential losses. For additional information on material legal and administrative proceedings, see Note 2 – Rate and Regulatory Matters, Note 9 – Commitments and Contingencies, and Note 10 – Callaway Energy Center, under Part I, Item 1, of this report. Pursuant to Item 103(c)(3)(iii) of Regulation S-K, our policy is to disclose environmental proceedings to which a governmental entity is a party if we reasonably believe such proceedings will result in monetary sanctions of $1 million or more.

ITEM 1A. RISK FACTORS.

For a detailed discussion of our risk factors, see the information disclosed in Part I, Item 1A, of the Form 10-K.

ITEM 2. UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS.

Ameren Corporation, Ameren Missouri, and Ameren Illinois did not purchase equity securities reportable under Item 703 of Regulation S-K during the period from July 1, 2026, to September 30, 2026.

ITEM 5. OTHER INFORMATION.

Insider Adoption or Termination of Trading Arrangements

During the fiscal quarter ended September 30, 2026, none of our directors or officers informed us of the adoption or termination of a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as those terms are defined in Regulation S-K, Item 408, except as follows:

On August 6, 2026, Theresa A. Shaw, Senior Vice President, Chief Accounting and Transformation Officer of Ameren, adopted a Rule 10b5-1 trading arrangement that provides for the sale of up to an aggregate of approximately 7,640 shares, consisting of:

78

---

Table of Contents

•up to 500 shares on a quarterly basis between November 2026 and November 2027, subject to certain price limitations set forth in the trading arrangement; and

•shares acquired upon vesting of certain equity awards, consisting of (i) 100% of shares delivered from the 2024 restricted stock units award scheduled to vest on March 1, 2027 (approximately 1,692 shares before applicable tax withholding), and (ii) 5% of shares delivered from the 2024 performance condition performance share units and 2024 market condition performance share units awards scheduled to vest on March 1, 2027 (approximately 564 shares and 3,384 shares, respectively, before applicable performance adjustments and tax withholding).

Ms. Shaw’s 10b5-1 trading arrangement will terminate on the earlier of: (i) November 16, 2027; (ii) execution of all trades or expiration of all orders relating to such trades under the Rule 10b5-1 trading arrangement; or (iii) such date as the Rule 10b5-1 trading arrangement is otherwise terminated according to its terms.

The trading arrangement discussed above is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

79

---

Table of Contents

ITEM 6. EXHIBITS.

The documents listed below are being filed or have previously been filed on behalf of the Ameren Companies and are incorporated herein by reference from the documents indicated and made a part hereof. Exhibits not identified as previously filed are filed herewith.

Exhibit Designation

Registrant(s)

Nature of Exhibit

Previously Filed as Exhibit to:

Instruments Defining Rights of Security Holders, Including Indentures

4.1

Ameren Ameren Illinois

Supplemental Indenture to the Ameren Illinois Mortgage, dated August 1, 2026, for 5.50% First Mortgage Bonds due 2036

August 24, 2026 Form 8-K, Exhibit 4.2, File No. 1-3672

4.2

Ameren

Note Purchase Agreement, dated as of August 6, 2026, between Ameren Transmission Company of Illinois and the several purchasers named therein

4.3

Ameren

Indenture, dated as of September 1, 2026, from Ameren to The Bank of New York Mellon Trust Company, N.A., as trustee, relating to subordinated debt securities

September 18, 2026 Form 8-K, Exhibit 4.1, File No. 1-14756

4.4

Ameren

Company Order, dated September 18, 2026, establishing the Junior Subordinated Notes due 2057 (including the global notes)

September 18, 2026 Form 8-K, Exhibits 4.2 and 4.3, File No. 1-14756

Rule 13a-14(a) / 15d-14(a) Certifications

31.1

Ameren

Rule 13a-14(a)/15d-14(a) Certification of Principal Executive Officer of Ameren

31.2

Ameren

Rule 13a-14(a)/15d-14(a) Certification of Principal Financial Officer of Ameren

31.3

Ameren Missouri

Rule 13a-14(a)/15d-14(a) Certification of Principal Executive Officer of Ameren Missouri

31.4

Ameren Missouri

Rule 13a-14(a)/15d-14(a) Certification of Principal Financial Officer of Ameren Missouri

31.5

Ameren Illinois

Rule 13a-14(a)/15d-14(a) Certification of Principal Executive Officer of Ameren Illinois

31.6

Ameren Illinois

Rule 13a-14(a)/15d-14(a) Certification of Principal Financial Officer of Ameren Illinois

Section 1350 Certifications

32.1

Ameren

Section 1350 Certification of Principal Executive Officer and Principal Financial Officer of Ameren

32.2

Ameren Missouri

Section 1350 Certification of Principal Executive Officer and Principal Financial Officer of Ameren Missouri

32.3

Ameren Illinois

Section 1350 Certification of Principal Executive Officer and Principal Financial Officer of Ameren Illinois

Interactive Data Files

101.INS

Ameren Companies

Inline XBRL Instance Document - the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document

101.SCH

Ameren Companies

Inline XBRL Taxonomy Extension Schema Document

101.CAL

Ameren Companies

Inline XBRL Taxonomy Extension Calculation Linkbase Document

101.LAB

Ameren Companies

Inline XBRL Taxonomy Extension Label Linkbase Document

101.PRE

Ameren Companies

Inline XBRL Taxonomy Extension Presentation Linkbase Document

101.DEF

Ameren Companies

Inline XBRL Taxonomy Extension Definition Document

104

Ameren Companies

Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)

*Compensatory plan or arrangement.

The file number references for the Ameren Companies’ filings with the SEC are: Ameren, 1-14756; Ameren Missouri, 1-2967; and Ameren Illinois, 1-3672.

Each registrant hereby undertakes to furnish to the SEC upon request a copy of any long-term debt instrument not listed above that such registrant has not filed as an exhibit pursuant to the exemption provided by Item 601(b)(4)(iii)(A) of Regulation S-K.

80

---

SIGNATURES

Pursuant to the requirements of the Exchange Act, each registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. The signature for each undersigned company shall be deemed to relate only to matters having reference to such company or its subsidiaries.

AMEREN CORPORATION (Registrant)
/s/ Leonard P. Singh
Leonard P. Singh Executive Vice President and Chief Financial Officer (Principal Financial Officer)
UNION ELECTRIC COMPANY (Registrant)
/s/ Leonard P. Singh
Leonard P. Singh Executive Vice President and Chief Financial Officer (Principal Financial Officer)
AMEREN ILLINOIS COMPANY (Registrant)
/s/ Leonard P. Singh
Leonard P. Singh Executive Vice President and Chief Financial Officer (Principal Financial Officer)

Date: November 6, 2026

81

Exhibit 4.2

Execution Version

Ameren Transmission Company of Illinois

$300,000,000

$140,000,000 5.83% Senior Notes, Series A, due August 6, 2041

and

$160,000,000 6.24% Senior Notes, Series B, due January 28, 2054

______________

Note Purchase Agreement

______________

Dated as of August 6, 2026

---

TABLE OF CONTENTS

SECTION    HEADING    PAGE

SECTION 1.    AUTHORIZATION OF NOTES    1

SECTION 2.    SALE AND PURCHASE OF NOTES    1

SECTION 3.    CLOSINGS    2

SECTION 4.    CONDITIONS TO EACH CLOSING    2

Section 4.1.    Representations and Warranties    2

Section 4.2.    Performance; No Default, Change of Control, or Control Event    2

Section 4.3.    Compliance Certificates    3

Section 4.4.    Opinions of Counsel    3

Section 4.5.    Purchase Permitted By Applicable Law, Etc    3

Section 4.6.    Sale of Other Notes    3

Section 4.7.    Payment of Special Counsel Fees    3

Section 4.8.    Private Placement Numbers    4

Section 4.9.    Changes in Corporate Structure    4

Section 4.10.    Closing Instructions    4

Section 4.11.    Governmental Approval    4

Section 4.12.    Proceedings and Documents    4

SECTION 5.    REPRESENTATIONS AND WARRANTIES OF THE COMPANY    4

Section 5.1.    Organization; Power and Authority    5

Section 5.2.    Authorization, Etc    5

Section 5.3.    Disclosure    5

Section 5.4.    Organization and Ownership of Shares of Subsidiaries; Affiliates    5

Section 5.5.    Financial Statements; Material Liabilities    5

Section 5.6.    Compliance with Laws, Other Instruments, Etc    6

Section 5.7.    Governmental Authorizations, Etc    6

Section 5.8.    Litigation; Observance of Statutes and Orders    6

Section 5.9.    Taxes    6

Section 5.10.    Title to Property; Leases    7

Section 5.11.    Licenses, Permits, Etc    7

Section 5.12.    Compliance with Employee Benefit Plans    7

Section 5.13.    Private Offering by the Company    8

Section 5.14.    Use of Proceeds; Margin Regulations    8

Section 5.15.    Existing Indebtedness    8

Section 5.16.    Foreign Assets Control Regulations, Etc    9

Section 5.17.    Status under Certain Statutes    10

-i-

---

SECTION 6.    REPRESENTATIONS OF THE PURCHASERS    10

Section 6.1.    Purchase for Investment    10

Section 6.2.    Source of Funds    10

Section 6.3.    Accredited Investor    12

Section 6.4.    Status Under OBBB    12

SECTION 7.    INFORMATION AS TO COMPANY    12

Section 7.1.    Financial and Business Information    12

Section 7.2.    Officer’s Certificate    14

Section 7.3.    Visitation    15

Section 7.4.     Electronic Delivery    16

SECTION 8.    PAYMENT AND PREPAYMENT OF THE NOTES    16

Section 8.1.    Maturity    16

Section 8.2.    Optional Prepayments with and Without Make-Whole Amount    17

Section 8.3.    Allocation of Partial Prepayments    18

Section 8.4.    Maturity; Surrender, Etc.    18

Section 8.5.    Purchase of Notes    18

Section 8.6.    Make-Whole Amount    18

Section 8.7.    Change of Control    20

Section 8.8.    Payments Due on Non-Business Days    21

SECTION 9.    AFFIRMATIVE COVENANTS.    22

Section 9.1.    Compliance with Laws    22

Section 9.2.    Insurance    22

Section 9.3.    Maintenance of Properties    22

Section 9.4.    Payment of Taxes    22

Section 9.5.    Corporate Existence, Etc    23

Section 9.6.    Books and Records    23

Section 9.7.    Guarantors    23

Section 9.8.    Notes to Rank Pari Passu    24

Section 9.9.    Energy Regulatory Status    24

Section 9.10.    Maintenance of Rating on the Notes    24

SECTION 10.    NEGATIVE COVENANTS.    25

Section 10.1.    Transactions with Affiliates    25

Section 10.2.    Merger, Consolidation, Etc    25

Section 10.3.    Sale of Assets    26

Section 10.4.    Line of Business    27

Section 10.5.    Economic Sanctions, Etc    28

Section 10.6.    Liens    28

-ii-

---

Section 10.7.    Financial Covenants    31

SECTION 11.    EVENTS OF DEFAULT    31

SECTION 12.    REMEDIES ON DEFAULT, ETC    33

Section 12.1.    Acceleration    33

Section 12.2.    Other Remedies    34

Section 12.3.    Rescission    34

Section 12.4.    No Waivers or Election of Remedies, Expenses, Etc    35

SECTION 13.    REGISTRATION; EXCHANGE; SUBSTITUTION OF NOTES    35

Section 13.1.    Registration of Notes    35

Section 13.2.    Transfer and Exchange of Notes    35

Section 13.3.    Replacement of Notes    36

SECTION 14.    PAYMENTS ON NOTES    36

Section 14.1.    Place of Payment    36

Section 14.2.    Payment by Wire Transfer    36

Section 14.3.    FATCA Information    37

SECTION 15.    EXPENSES, ETC    37

Section 15.1.    Transaction Expenses    37

Section 15.2.    Certain Taxes    38

Section 15.3.    Survival    38

SECTION 16.    SURVIVAL OF REPRESENTATIONS AND WARRANTIES; ENTIRE AGREEMENT    38

SECTION 17.    AMENDMENT AND WAIVER    39

Section 17.1.    Requirements    39

Section 17.2.    Solicitation of Holders of Notes    39

Section 17.3.    Binding Effect, Etc    40

Section 17.4.    Notes Held by Company, Etc    40

SECTION 18.    NOTICES    40

SECTION 19.    REPRODUCTION OF DOCUMENTS    41

SECTION 20.    CONFIDENTIAL INFORMATION    41

SECTION 21.    SUBSTITUTION OF PURCHASER    42

SECTION 22.    MISCELLANEOUS    43

-iii-

---

Section 22.1.    Successors and Assigns    43

Section 22.2.    Accounting Terms    43

Section 22.3.    Severability    43

Section 22.4.    Construction, Etc    43

Section 22.5.    Counterparts; Signatures    44

Section 22.6.    Governing Law    44

Section 22.7.    Jurisdiction and Process; Waiver of Jury Trial    44

Signature    46

-iv-

---

Schedule A    —    Defined Terms

Schedule 1(a)    —    Form of 5.83% Senior Note, Series A, due August 6, 2041

Schedule 1(b)    —    Form of 6.24% Senior Note, Series B, due January 28, 2054

Schedule 4.4(a) —    Form of Opinion of Counsel for the Company

Schedule 4.4(b) —    Form of Opinion of Counsel for the Company

Schedule 4.4(c) —    Form of Opinion of Special Counsel for the Purchasers

Schedule 5.3    —    Disclosure Materials

Schedule 5.4    —    Affiliates, Directors, and Senior Officers

Schedule 5.5    —    Financial Statements

Schedule 5.7    —    Required Approvals and Filings to be made by the Company

Schedule 5.15    —    Existing Indebtedness

Schedule 10.6    —    Existing Liens

Purchaser Schedule    —    Information Relating to Purchasers

Exhibit 14.3    —    Form of U.S. Tax Compliance Certificate

-v-

---

Ameren Transmission Company of Illinois

1901 Chouteau Avenue

St. Louis, Missouri 63103

$140,000,000 5.83% Senior Notes, Series A, due August 6, 2041

$160,000,000 6.24% Senior Notes, Series B, due January 28, 2054

August 6, 2026

To Each of the Purchasers Listed in

    the Purchaser Schedule Hereto:

Ladies and Gentlemen:

Ameren Transmission Company of Illinois, an Illinois corporation (the “Company”), agrees with each of the Purchasers as follows:

Section 1.    Authorization of Notes.

The Company will authorize the issue and sale of (i) $140,000,000 aggregate principal amount of its 5.83% Senior Notes, Series A, due August 6, 2041 (the “Series A Notes”) and (ii) $160,000,000 aggregate principal amount of its 6.24% Senior Notes, Series B, due January 28, 2054 (the “Series B Notes” and, together with the Series A Notes, collectively, the “Notes,” such term to include any such notes issued in substitution therefor pursuant to Section 14). The Series A Notes shall be substantially in the form set out in Schedule 1(a) and the Series B Notes shall be substantially in the form set out in Schedule 1(b). Each series of Notes is sometimes referred to herein as a “series”. Certain capitalized and other terms used in this Agreement are defined in Schedule A and, for purposes of this Agreement, the rules of construction set forth in Section 22.4 shall govern.

Section 2.    Sale and Purchase of Notes.

Subject to the terms and conditions of this Agreement, the Company will issue and sell to each Purchaser and each Purchaser will purchase from the Company, at each Closing provided for in Section 3, Notes of the series and in the applicable principal amount specified opposite such Purchaser’s name in the Purchaser Schedule at the purchase price of 100% of the principal amount thereof. The Purchasers’ obligations hereunder are several and not joint obligations and no Purchaser shall have any liability to any Person for the performance or non-performance of any obligation by any other Purchaser hereunder.

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

Section 3.    Closings.

The execution and delivery of this Agreement and the sale and purchase of the Series A Notes will be made at the offices of Chapman and Cutler LLP, 320 South Canal Street, Chicago, Illinois 60606 at 10:00 a.m., Chicago time, on August 6, 2026 (the “First Closing”). The sale and purchase of the Series B Notes shall occur at the offices of Chapman and Cutler LLP, 320 South Canal Street, Chicago, Illinois 60606 at 10:00 a.m., Chicago time, on January 28, 2027 (the “Second Closing”; the First Closing and the Second Closing shall be each referred to individually as a “Closing”). On the date of the applicable Closing, the Company will deliver to each Purchaser the respective Notes to be purchased by such Purchaser at such Closing in the form of a single Note of the applicable series (or such greater number of Notes in denominations of at least $100,000 as such Purchaser may request) dated the date of the applicable Closing and registered in such Purchaser’s name (or in the name of its nominee), against delivery by such Purchaser to the Company or its order of immediately available funds in the amount of the purchase price therefor by wire transfer of immediately available funds for the account of the Company to account number 130110607301 at US Bank, Account Name: Ameren Transmission Company of Illinois, ABA Number: 042000013. If, on the date of the applicable Closing, the Company shall fail to tender such Notes to any Purchaser as provided above in this Section 3, or any of the conditions specified in Section 4 shall not have been fulfilled to such Purchaser’s satisfaction, such Purchaser shall, at its election, be relieved of all further obligations under this Agreement, without thereby waiving any rights such Purchaser may have by reason of such failure by the Company to tender such Notes or any of the conditions specified in Section 4 not having been fulfilled to such Purchaser’s satisfaction. If, on the date of the applicable Closing, one or more Purchasers shall fail to purchase Notes which such Purchaser(s) is obligated to purchase under this Agreement, the Company shall have the option of terminating its obligation to sell any Notes only to such defaulting Purchaser(s) and be relieved of all further obligations under this Agreement only with respect to such defaulting Purchaser(s).

Section 4.    Conditions to Each Closing.

Each Purchaser’s obligation to purchase and pay for the Notes to be sold to such Purchaser at the applicable Closing is subject to the fulfillment to such Purchaser’s satisfaction, prior to or at the applicable Closing, of the following conditions:

    Section 4.1.    Representations and Warranties. The representations and warranties of the Company in this Agreement shall be correct when made and at each Closing (except with respect to representations and warranties made as of a specific date, in which case they shall be correct as of such date).

    Section 4.2.    Performance; No Default, Change of Control, or Control Event. The Company shall have performed and complied with all agreements and conditions contained in this Agreement required to be performed or complied with by it prior to or at each Closing. From the date of this Agreement until the Second Closing, before and after giving effect to the issue and sale of the Notes (and the application of the proceeds thereof as contemplated by Section 5.14), (i) no Default or Event of Default shall have occurred and be continuing, and (ii) no Change of Control or Control Event shall have occurred. Neither the Company nor any

-2-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

Subsidiary shall have entered into any transaction since the date of this Agreement that would have been prohibited by Section 10.

    Section 4.3.    Compliance Certificates.

    (a)    Officer’s Certificate. The Company shall have delivered to such Purchaser an Officer’s Certificate, dated the date of the applicable Closing, certifying that the conditions specified in Sections 4.1, 4.2, and 4.9 have been fulfilled.

    (b)    Secretary’s Certificate. The Company shall have delivered to such Purchaser a certificate of the Secretary, the Deputy Corporate Secretary or an Assistant Secretary of the Company, dated the date of the applicable Closing, certifying as to (i) the resolutions attached thereto and other corporate proceedings relating to the authorization, execution and delivery of the Notes to be issued at each Closing and this Agreement and (ii) the Company’s organizational documents as then in effect.

Section 4.4.    Opinions of Counsel. Such Purchaser shall have received opinions in form and substance satisfactory to such Purchaser, dated the date of the applicable Closing (a) from David M. Feinberg, Esq., Executive Vice President, General Counsel and Secretary of the Company, or another counsel chosen by the Company, and Morgan, Lewis & Bockius LLP, counsel for the Company, covering the matters set forth in Schedules 4.4(a) and 4.4(b), respectively, (and the Company hereby instructs its counsel to deliver such opinion to the Purchasers) and (b) from Chapman and Cutler LLP, the Purchasers’ special counsel in connection with such transactions, substantially in the form set forth in Schedule 4.4(c) and covering such other matters incident to such transactions as such Purchaser may reasonably request.

    Section 4.5.    Purchase Permitted By Applicable Law, Etc. On the date of the applicable Closing such Purchaser’s purchase of Notes to be issued at the applicable Closing shall (a) be permitted by the laws and regulations of each jurisdiction to which such Purchaser is subject, without recourse to provisions (such as section 1405(a)(8) of the New York Insurance Law) permitting limited investments by insurance companies without restriction as to the character of the particular investment, (b) not violate any applicable law or regulation (including Regulation T, U or X of the Board of Governors of the Federal Reserve System) and (c) not subject such Purchaser to any tax, penalty or liability under or pursuant to any applicable law or regulation, which law or regulation was not in effect on the date hereof. If requested by such Purchaser, such Purchaser shall have received an Officer’s Certificate certifying as to such matters of fact as such Purchaser may reasonably specify to enable such Purchaser to determine whether such purchase is so permitted.

    Section 4.6.    Sale of Other Notes. Contemporaneously with the applicable Closing, the Company shall sell to each Purchaser and each Purchaser shall purchase the Notes to be purchased by it at such Closing as specified in the Purchaser Schedule.

    Section 4.7.    Payment of Special Counsel Fees. Without limiting Section 15.1, the Company shall have paid on or before each Closing the fees, charges and disbursements of the

-3-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

Purchasers’ special counsel referred to in Section 4.4 to the extent reflected in a statement of such counsel rendered to the Company at least one Business Day prior to each Closing.

    Section 4.8.    Private Placement Numbers. A Private Placement Number issued by CUSIP Global Services (in cooperation with the SVO) shall have been obtained for each series of the Notes.

    Section 4.9.    Changes in Corporate Structure. The Company shall not have changed its jurisdiction of incorporation or organization, as applicable, or been a party to any merger or consolidation or succeeded to all or any substantial part of the liabilities of any other entity, at any time following the date of the most recent financial statements referred to in Schedule 5.5.

    Section 4.10.    Closing Instructions. At least five (5) Business Days prior to the date of the applicable Closing, each Purchaser shall have received written instructions signed by a Responsible Officer on letterhead of the Company confirming the information specified in Section 3 including (a) the name and address of the transferee bank, (b) such transferee bank’s ABA number and (c) the account name and number into which the purchase price for the Notes is to be deposited. Each Purchaser has the right, but not the obligation, upon written notice (which may be by email) to the Company, to elect to deliver a micro deposit (less than $51.00) to the account identified in the written instructions no later than two (2) Business Days prior to the applicable Closing.  If a Purchaser delivers a micro deposit, a Responsible Officer or an Assistant Treasurer of the Company, or an employee of the Company or an Affiliate of the Company designated by a Responsible Officer or an Assistant Treasurer of the Company, will verbally verify the receipt and amount of the micro deposit to such Purchaser on a telephone call initiated by such Purchaser prior to the applicable Closing. The Company shall not be obligated to return the amount of the micro deposit, nor will the amount of the micro deposit be netted against the Purchaser’s purchase price of the Notes.

    Section 4.11.    Governmental Approval. All approvals of any Governmental Authority required to be in effect in connection with the issuance and sale of the Notes hereunder at each Closing shall have been obtained and be in full force and effect, no materially adverse action has been taken by any applicable authority, and copies of the documentation thereof shall have been delivered to each Purchaser.

    Section 4.12.    Proceedings and Documents. All corporate and other proceedings in connection with the transactions contemplated by this Agreement and all documents and instruments incident to such transactions shall be satisfactory to such Purchaser and its special counsel, and such Purchaser and its special counsel shall have received all such counterpart originals or certified or other copies of such documents as such Purchaser or such special counsel may reasonably request.

Section 5.    Representations and Warranties of the Company.

The Company represents and warrants to each Purchaser, as of the date of this Agreement and each Closing that:

-4-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

    Section 5.1.    Organization; Power and Authority. The Company is a corporation duly organized, validly existing and in good standing under the laws of its jurisdiction of incorporation, and is duly qualified as a foreign corporation and is in good standing in each jurisdiction in which such qualification is required by law, other than those jurisdictions as to which the failure to be so qualified or in good standing would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect. The Company has the corporate power and authority to own or hold under lease the properties it purports to own or hold under lease, to transact the business it transacts and proposes to transact, to execute and deliver this Agreement and the Notes and to perform the provisions hereof and thereof.

    Section 5.2.    Authorization, Etc. This Agreement and the Notes have been duly authorized by all necessary corporate action on the part of the Company, and this Agreement constitutes, and upon execution and delivery thereof each Note will constitute, a legal, valid and binding obligation of the Company enforceable against the Company in accordance with its terms, except as such enforceability may be limited by (i) applicable bankruptcy, insolvency, reorganization, moratorium or other similar laws affecting the enforcement of creditors’ rights generally and (ii) general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law).

    Section 5.3.    Disclosure. The Company, through its agents, PNC Capital Markets LLC and Scotia Capital (USA) Inc., has made the Disclosure Documents available to each Purchaser (including the Investor Presentation dated July 2026 (identified in Schedule 5.3) (the “Investor Presentation”). This Agreement, the Investor Presentation, the financial statements listed in Schedule 5.5 and the documents, certificates or other writings delivered or made available to the Purchasers by or on behalf of the Company, or to which the Purchasers were directed or referred by or on behalf of the Company, prior to July 21, 2026 in connection with the transactions contemplated hereby and identified in Schedule 5.3 (this Agreement, the Investor Presentation, and such documents, certificates or other writings and such financial statements delivered or made available to each Purchaser being referred to, collectively, as the “Disclosure Documents”), taken as a whole, do not contain any untrue statement of a material fact or omit to state any material fact necessary to make the statements therein not misleading in light of the circumstances under which they were made. Except as disclosed in the Disclosure Documents, since December 31, 2025, there has been no change in the financial condition, operations, business or properties of the Company or any Subsidiary except changes that would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

    Section 5.4.    Organization and Ownership of Shares of Subsidiaries; Affiliates. The Company has no Subsidiaries as of the date hereof. Schedule 5.4 contains (except as noted therein) complete and correct lists as of the date hereof of (i) the Company’s Affiliates that are Material, and (ii) the Company’s directors and senior officers.

    Section 5.5.    Financial Statements; Material Liabilities. The Company, through its agents, PNC Capital Markets LLC and Scotia Capital (USA) Inc., has made available to each Purchaser copies of the financial statements of the Company listed on Schedule 5.5. All of such financial statements (including in each case the related schedules and notes) fairly present in all material respects the financial position of the Company as of the respective dates specified in

-5-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

such financial statements and the results of its operations and cash flows for the respective periods so specified and have been prepared in accordance with GAAP consistently applied throughout the periods involved except as set forth in the notes thereto (subject, in the case of any interim financial statements, to normal year-end adjustments). The Company does not have any Material liabilities that are not disclosed in the Disclosure Documents, except changes in the aggregate amount of Indebtedness after the First Closing permitted within the limitations of this Agreement.

    Section 5.6.    Compliance with Laws, Other Instruments, Etc. The execution, delivery and performance by the Company of this Agreement and the Notes will not (i) contravene, result in any breach of, or constitute a default under, or result in the creation of any Lien in respect of any property of the Company under, any indenture, mortgage, deed of trust, loan, purchase or credit agreement, lease, corporate charter, regulations or bylaws, shareholders agreement or any other agreement or instrument to which the Company is bound or by which the Company or any of its properties may be bound or affected, (ii) conflict with or result in a breach of any of the terms, conditions or provisions of any order, judgment, decree or ruling of any court, arbitrator or Governmental Authority applicable to the Company or (iii) violate any provision of any statute or other rule or regulation of any Governmental Authority applicable to the Company

    Section 5.7.    Governmental Authorizations, Etc. No consent, approval or authorization of, or registration, filing or declaration with, any Governmental Authority is required in connection with the execution, delivery or performance by the Company of this Agreement or the Notes other than (a) such approvals of Governmental Authorities contemplated by Section 4.11 and as described in Schedule 5.7 which have been obtained or made and which shall be in full force and effect at each Closing and (b) filings required to be made after the First Closing and as described in Schedule 5.7.

    Section 5.8.    Litigation; Observance of Statutes and Orders. (a) There are no actions, suits, investigations or proceedings pending or, to the best knowledge of the Company, threatened against or affecting the Company or any property of the Company in any court or before any arbitrator of any kind or before or by any Governmental Authority that would, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

    (b)    The Company is not (i) in violation of any order, judgment, decree or ruling of any court, any arbitrator of any kind or any Governmental Authority or (ii) in violation of any applicable law, ordinance, rule or regulation of any Governmental Authority (including Environmental Laws, the USA PATRIOT Act or any of the other laws and regulations that are referred to in Section 5.16), which violation would, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

    Section 5.9.    Taxes. The Company has filed all tax returns that are required to have been filed by the Company in any jurisdiction, and has paid all taxes shown to be due and payable on such returns and all other taxes and assessments levied upon it or its properties, assets, income or franchises, to the extent such taxes and assessments have become due and payable and before they have become delinquent, except for any taxes and assessments (i) the amount of which, individually or in the aggregate, is not Material or (ii) the amount, applicability or validity of

-6-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

which is currently being contested in good faith by appropriate proceedings and with respect to which the Company has established adequate reserves in accordance with GAAP. The charges, accruals and reserves on the books of the Company in respect of U.S. federal, state or other taxes for all fiscal periods are adequate. As of the date hereof, the U.S. federal income tax liabilities of the Company have been finally determined (whether by reason of completed audits or the statute of limitations having run) for all fiscal years up to and including the fiscal year ended December 31, 2024.

    Section 5.10.    Title to Property; Leases. The Company has good and sufficient title to its Material properties, including all such Material properties reflected in the most recent audited balance sheet referred to in Section 5.5 or purported to have been acquired by the Company after such date (except as sold or otherwise disposed of in the ordinary course of business), in each case free and clear of Liens prohibited by this Agreement, except for those defects in title and Liens that, individually or in the aggregate, would not have a Material Adverse Effect. All Material leases are valid and subsisting and are in full force and effect in all material respects.

    Section 5.11.    Licenses, Permits, Etc. The Company owns or possesses all licenses, permits, franchises, authorizations, patents, copyrights, proprietary software, service marks, trademarks and trade names, or rights thereto, that individually or in the aggregate are Material, without known conflict with the rights of others, except for those conflicts that, individually or in the aggregate, would not have a Material Adverse Effect.

    Section 5.12.    Compliance with Employee Benefit Plans. (a) The Company and each ERISA Affiliate have operated and administered each Plan in compliance with all applicable laws except for such instances of noncompliance as have not resulted in and could not, individually or in the aggregate, reasonably be expected to result in a Material Adverse Effect.  Neither the Company nor any ERISA Affiliate has incurred any liability pursuant to Title I or IV of ERISA or the penalty or excise tax provisions of the Code relating to employee benefit plans (as defined in section 3 of ERISA), and no event, transaction or condition has occurred or exists that would, individually or in the aggregate, reasonably be expected to result in the incurrence of any such liability by the Company or any ERISA Affiliate, or in the imposition of any Lien on any of the rights, properties or assets of the Company or any ERISA Affiliate, in either case pursuant to Title I or IV of ERISA or to section 430(k) of the Code or to any such penalty or excise tax provisions under the Code or federal law or section 4068 of ERISA or by the granting of a security interest in connection with the amendment of a Plan, other than such liabilities or Liens as would not be individually or in the aggregate Material.

    (b)    The present value of the aggregate benefit liabilities under each of the Plans (other than Multiemployer Plans, other than “employee welfare benefit plans” as defined in section 3(1) of ERISA, and other than Plans that are not subject to Title IV of ERISA), determined as of the end of such Plan’s most recently ended plan year on the basis of the actuarial assumptions specified for funding purposes in such Plan’s most recent actuarial valuation report, did not exceed the aggregate current value of the assets of such Plan allocable to such benefit liabilities. The term “benefit liabilities” has the meaning specified in section 4001 of ERISA and the terms “current value” and “present value” have the meaning specified in section 3 of ERISA.

-7-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

    (c)    The Company and its ERISA Affiliates have not incurred (i) withdrawal liabilities (and are not subject to contingent withdrawal liabilities) under sections 4201 or 4204 of ERISA in respect of Multiemployer Plans that individually or in the aggregate are Material or (ii) any obligation in connection with the termination of or withdrawal from any Non-U.S. Plan that individually or in the aggregate are Material.

    (d)    The expected postretirement benefit obligation (determined as of the last day of the Company’s most recently ended fiscal year in accordance with Financial Accounting Standards Board Accounting Standards Codification Topic 715-60, without regard to liabilities attributable to continuation coverage mandated by section 4980B of the Code) of the Company is not Material.

    (e)    The execution and delivery of this Agreement and the issuance and sale of the Notes hereunder will not involve any transaction that is subject to the prohibitions of section 406 of ERISA or in connection with which a tax could be imposed pursuant to section 4975(c)(1)(A)-(D) of the Code. The representation by the Company to each Purchaser in the first sentence of this Section 5.12(e) is made in reliance upon and subject to the accuracy of such Purchaser’s representation in Section 6.2 as to the sources of the funds to be used to pay the purchase price of the Notes to be purchased by such Purchaser.

    (f)    The Company does not have any Non-U.S. Plans.

    Section 5.13.    Private Offering by the Company. Neither the Company nor anyone acting on its behalf has offered the Notes or any similar Securities for sale to, or solicited any offer to buy the Notes or any similar Securities from, or otherwise approached or negotiated in respect thereof with, any Person other than not more than 40 Institutional Investors (including the Purchasers), each of which has been offered the Notes at a private sale for investment. Neither the Company nor anyone acting on its behalf has taken, or will take, any action that would subject the issuance or sale of the Notes to the registration requirements of section 5 of the Securities Act or to the registration requirements of any Securities or blue sky laws of any applicable jurisdiction.

    Section 5.14.    Use of Proceeds; Margin Regulations. The Company will apply the proceeds of the sale of the Notes hereunder to refund, redeem and/or refinance existing Indebtedness and to pay expenses in connection with the issuance of the Notes. No part of the proceeds from the sale of the Notes hereunder will be used, directly or indirectly, for the purpose of buying or carrying any margin stock within the meaning of Regulation U of the Board of Governors of the Federal Reserve System (12 CFR 221), or for the purpose of buying or carrying or trading in any Securities under such circumstances as to involve the Company in a violation of Regulation X of said Board (12 CFR 224) or to involve any broker or dealer in a violation of Regulation T of said Board (12 CFR 220). Margin stock does not constitute more than 5% of the value of the consolidated assets of the Company and its Subsidiaries and the Company does not have any present intention that margin stock will constitute more than 5% of the value of such assets. As used in this Section, the terms “margin stock” and “purpose of buying or carrying” shall have the meanings assigned to them in said Regulation U.

-8-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

    Section 5.15.    Existing Indebtedness. (a) Except as described therein, Schedule 5.15 sets forth a complete and correct list of all outstanding Indebtedness of the Company as of the date of the First Closing (including descriptions of the obligors and obligees, principal amounts outstanding as of the dates specified in Schedule 5.15, any collateral therefor and any Guaranty thereof), since which date there has been no Material change in the amounts, interest rates, sinking funds, installment payments or maturities of the Indebtedness of the Company, except changes in the aggregate amount of Indebtedness after the First Closing permitted within the limitations of this Agreement. The Company is not in default, and no waiver of default is currently in effect, in the payment of any principal or interest on any such Indebtedness of the Company and no event or condition exists with respect to any such Indebtedness of the Company the outstanding principal amount of which exceeds $1,000,000 that would permit (or that with notice or the lapse of time, or both, would permit) one or more Persons to cause such Indebtedness to become due and payable before its stated maturity or before its regularly scheduled dates of payment.

    (b)    The Company is not a party to, or otherwise subject to any provision contained in, any instrument evidencing Indebtedness of the Company, any agreement relating thereto or any other agreement (including its charter or any other organizational document) which limits the amount of, or otherwise imposes restrictions on the incurring of, Indebtedness of the Company, except as disclosed in Schedule 5.15.

    (c)    Except as disclosed in Schedule 5.15, the Company has not agreed or consented to cause or permit in the future (upon the happening of a contingency or otherwise) any of its Material property, whether now owned or hereafter acquired, to be subject to a Lien not permitted by Section 10.6.

        Section 5.16.    Foreign Assets Control Regulations, Etc. (a) Neither the Company nor any Controlled Entity (i) is a Blocked Person, (ii) has been notified that its name appears or may in the future appear on a State Sanctions List or (iii) is a target of sanctions that have been imposed by the United Nations or the European Union.

    (b)    Neither the Company nor any Controlled Entity (i) has violated, been found in violation of, or been charged or convicted under, any applicable U.S. Economic Sanctions Laws, Anti-Money Laundering Laws or Anti-Corruption Laws or (ii) to the Company’s knowledge, is under investigation by any Governmental Authority for possible violation of any U.S. Economic Sanctions Laws, Anti-Money Laundering Laws or Anti-Corruption Laws.

    (c)    No part of the proceeds from the sale of the Notes hereunder:

    (i)    constitutes or will constitute funds obtained on behalf of any Blocked Person or will otherwise be used by the Company or any Controlled Entity, directly or indirectly, (A) in connection with any investment in, or any transactions or dealings with, any Blocked Person, (B) for any purpose that would cause any Purchaser to be in violation of any U.S. Economic Sanctions Laws or (C) otherwise in violation of any U.S. Economic Sanctions Laws;

-9-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

    (ii)    will be used, directly or indirectly, in violation of, or cause any Purchaser to be in violation of, any applicable Anti-Money Laundering Laws; or

    (iii)    will be used, directly or indirectly, for the purpose of making any improper payments, including bribes, to any Governmental Official or commercial counterparty in order to obtain, retain or direct business or obtain any improper advantage, in each case which would be in violation of, or cause any Purchaser to be in violation of, any applicable Anti-Corruption Laws.

    (d)    The Company has established procedures and controls which it reasonably believes are adequate (and otherwise comply with applicable law) to ensure that the Company and each Controlled Entity is and will continue to be in compliance with all applicable U.S. Economic Sanctions Laws, Anti-Money Laundering Laws and Anti-Corruption Laws.

    Section 5.17.    Status under Certain Statutes. The Company is not subject to regulation under the Investment Company Act of 1940, as amended, or the ICC Termination Act of 1995. The Company is subject to regulation under the Federal Power Act, as amended. Ameren is a public utility holding company under the Public Utility Holding Company Act of 2005, as amended.

Section 6.    Representations of the Purchasers.

    Section 6.1.    Purchase for Investment. Each Purchaser severally represents that it is purchasing the Notes for its own account or for one or more separate accounts maintained by such Purchaser or for the account of one or more pension or trust funds and not with a view to the distribution thereof, provided that the disposition of such Purchaser’s or their property shall at all times be within such Purchaser’s or their control. Each Purchaser understands that the Notes have not been registered under the Securities Act and may be resold only if registered pursuant to the provisions of the Securities Act or if an exemption from registration is available, except under circumstances where neither such registration nor such an exemption is required by law, and that the Company is not required to register the Notes.

    Section 6.2.    Source of Funds. Each Purchaser severally represents that at least one of the following statements is an accurate representation as to each source of funds (a “Source”) to be used by such Purchaser to pay the purchase price of the Notes to be purchased by such Purchaser hereunder:

    (a)    the Source is an “insurance company general account” (as the term is defined in the United States Department of Labor’s Prohibited Transaction Exemption (“PTE”) 95-60) in respect of which the reserves and liabilities (as defined by the annual statement for life insurance companies approved by the NAIC (the “NAIC Annual Statement”)) for the general account contract(s) held by or on behalf of any employee benefit plan together with the amount of the reserves and liabilities for the general account contract(s) held by or on behalf of any other employee benefit plans maintained by the same employer (or affiliate thereof as defined in PTE 95-60) or by the same employee organization in the general account do not exceed 10% of the total reserves and

-10-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

liabilities of the general account (exclusive of separate account liabilities) plus surplus as set forth in the NAIC Annual Statement filed with such Purchaser’s state of domicile; or

    (b)    the Source is a separate account that is maintained solely in connection with such Purchaser’s fixed contractual obligations under which the amounts payable, or credited, to any employee benefit plan (or its related trust) that has any interest in such separate account (or to any participant or beneficiary of such plan (including any annuitant)) are not affected in any manner by the investment performance of the separate account; or

    (c)    the Source is either (i) an insurance company pooled separate account, within the meaning of PTE 90-1 or (ii) a bank collective investment fund, within the meaning of the PTE 91-38 and, except as disclosed by such Purchaser to the Company in writing pursuant to this clause (c), no employee benefit plan or group of plans maintained by the same employer or employee organization beneficially owns more than 10% of all assets allocated to such pooled separate account or collective investment fund; or

    (d)    the Source constitutes assets of an “investment fund” (within the meaning of Part VI of PTE 84-14 (the “QPAM Exemption”)) managed by a “qualified professional asset manager” or “QPAM” (within the meaning of Part VI of the QPAM Exemption), no employee benefit plan’s assets that are managed by the QPAM in such investment fund, when combined with the assets of all other employee benefit plans established or maintained by the same employer or by an affiliate (within the meaning of Part VI(c)(1) of the QPAM Exemption) of such employer or by the same employee organization and managed by such QPAM, represent more than 20% of the total client assets managed by such QPAM, the conditions of Part I(c) and (g) of the QPAM Exemption are satisfied, neither the QPAM nor a person controlling or controlled by the QPAM maintains an ownership interest in the Company that would cause the QPAM and the Company to be “related” within the meaning of Part VI(h) of the QPAM Exemption and (i) the identity of such QPAM and (ii) the names of any employee benefit plans whose assets in the investment fund, when combined with the assets of all other employee benefit plans established or maintained by the same employer or by any affiliate (within the meaning of Part VI(c)(1) of the QPAM Exemption) of such employer or by the same employee organization, represent 10% or more of the assets of such investment fund, have been disclosed to the Company in writing pursuant to this clause (d); or

    (e)    the Source constitutes assets of a “plan(s)” (within the meaning of Part IV(h) of PTE 96-23 (the “INHAM Exemption”)) managed by an “in-house asset manager” or “INHAM” (within the meaning of Part IV(a) of the INHAM Exemption), the conditions of Part I(a), (g) and (h) of the INHAM Exemption are satisfied, neither the INHAM nor a person controlling or controlled by the INHAM (applying the definition of “control” in Part IV(d)(3) of the INHAM Exemption) owns a 10% or more interest in the Company and (i) the identity of such INHAM and (ii) the name(s) of the employee benefit plan(s) whose assets constitute the Source have been disclosed to the Company in writing pursuant to this clause (e); or

-11-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

    (f)    the Source is a governmental plan; or

    (g)    the Source is one or more employee benefit plans, or a separate account or trust fund comprised of one or more employee benefit plans, each of which has been identified to the Company in writing pursuant to this clause (g); or

    (h)    the Source does not include assets of any employee benefit plan, other than a plan exempt from the coverage of ERISA.

As used in this Section 6.2, the terms “employee benefit plan,” “governmental plan,” and “separate account” shall have the respective meanings assigned to such terms in section 3 of ERISA.

    Section 6.3.    Accredited Investor. Each Purchaser severally represents that it is an “accredited investor” as such term is defined in Regulation D promulgated pursuant to the Securities Act.

Section 6.4.    Status Under OBBB. Each Purchaser severally represents that it is neither a “Specified Foreign Entity” nor a “Foreign-Influenced Entity” as defined in the OBBB.

Section 7.    Information as to Company.

    Section 7.1.    Financial and Business Information. The Company shall deliver to each Purchaser and each holder of a Note that is an Institutional Investor:

    (a)    Quarterly Statements — within 60 days (or such shorter period as is the earlier of (x) 15 days greater than the period applicable to the filing of the Company’s Quarterly Report on Form 10-Q (the “Form 10-Q”), if any, with the SEC regardless of whether the Company is subject to the filing requirements thereof and (y) the date by which such financial statements are required to be delivered under any Material Credit Facility or the date on which such corresponding financial statements are delivered under any Material Credit Facility if such delivery occurs earlier than such required delivery date) after the end of each quarterly fiscal period in each fiscal year of the Company (other than the last quarterly fiscal period of each such fiscal year), duplicate copies of,

    (i)    a consolidated balance sheet of the Company and its Subsidiaries as at the end of such quarter, and

    (ii)    consolidated statements of income and cash flows of the Company and its Subsidiaries, for the portion of the fiscal year ending with such quarter (i.e., year-to-date statements),

setting forth in each case in comparative form the figures for the corresponding periods in the previous fiscal year, all in reasonable detail, prepared in accordance with GAAP applicable to such financial statements generally (but excluding notes to such financial statements), and certified by a Senior Financial Officer as fairly presenting, in all material

-12-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

respects, the financial position of the companies being reported on and their results of operations and cash flows, subject to changes resulting from year-end adjustments;

    (b)    Annual Statements — within 120 days (or such shorter period as is the earlier of (x) 15 days greater than the period applicable to the filing of the Company’s Annual Report on Form 10-K (the “Form 10-K”), if any, with the SEC regardless of whether the Company is subject to the filing requirements thereof and (y) the date by which such financial statements are required to be delivered under any Material Credit Facility or the date on which such corresponding financial statements are delivered under any Material Credit Facility if such delivery occurs earlier than such required delivery date) after the end of each fiscal year of the Company, duplicate copies of

    (i)    a consolidated balance sheet of the Company and its Subsidiaries as at the end of such year, and

    (ii)    consolidated statements of income, changes in shareholders’ equity and cash flows of the Company and its Subsidiaries for such year,

setting forth in each case in comparative form the figures for the previous fiscal year, all in reasonable detail, prepared in accordance with GAAP, and accompanied by an opinion thereon (without a “going concern” or similar qualification or exception and without any qualification or exception as to the scope of the audit on which such opinion is based) of independent public accountants of recognized national standing, which opinion shall state that such financial statements present fairly, in all material respects, the financial position of the companies being reported upon and their results of operations and cash flows and have been prepared in conformity with GAAP, and that the examination of such accountants in connection with such financial statements has been made in accordance with generally accepted auditing standards, and that such audit provides a reasonable basis for such opinion in the circumstances;

    (c)    SEC and Other Reports — promptly upon their becoming available, one copy of (i) each financial statement, report, notice, proxy statement or similar document sent by the Company or any Subsidiary (x) to its creditors under any Material Credit Facility (excluding information sent to such creditors in the ordinary course of administration of a credit facility, such as information relating to pricing and borrowing availability) or (y) to its public Securities holders generally, and (ii) each regular or periodic report, each registration statement (without exhibits except as expressly requested by such holder), and each prospectus and all amendments thereto filed by the Company or any Subsidiary with the SEC;

    (d)    Notice of Default or Event of Default — promptly, and in any event within 5 days after a Responsible Officer becoming aware of the existence of any Default or Event of Default, a written notice specifying the nature and period of existence thereof and what action the Company is taking or proposes to take with respect thereto;

-13-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

    (e)    Employee Benefits Matters — promptly, and in any event within 5 days after a Responsible Officer becoming aware of any of the following, a written notice setting forth the nature thereof and the action, if any, that the Company or an ERISA Affiliate proposes to take with respect thereto:

    (i)    with respect to any Plan, any reportable event, as defined in section 4043(c) of ERISA and the regulations thereunder, for which notice thereof has not been waived pursuant to such regulations as in effect on the date hereof and which would reasonably be expected to have a Material Adverse Effect;

    (ii)    the taking by the PBGC of steps to institute, or the threatening by the PBGC of the institution of, proceedings under section 4042 of ERISA for the termination of, or the appointment of a trustee to administer, any Plan, or the receipt by the Company or any ERISA Affiliate of a notice from a Multiemployer Plan that such action has been taken by the PBGC with respect to such Multiemployer Plan;

    (iii)    any event, transaction or condition that could result in the incurrence of any liability by the Company or any ERISA Affiliate pursuant to Title I of ERISA or Title IV of ERISA or the penalty or excise tax provisions of the Code relating to employee benefit plans, or in the imposition of any Lien on any of the rights, properties or assets of the Company or any ERISA Affiliate pursuant to Title I or IV of ERISA or such penalty or excise tax provisions, if such liability or Lien, taken together with any other such liabilities or Liens then existing, would reasonably be expected to have a Material Adverse Effect; or

    (iv)    receipt of notice of the imposition of a Material financial penalty (which for this purpose shall mean any tax, penalty or other liability, whether by way of indemnity or otherwise) with respect to one or more Non-U.S. Plans;

    (f)    Resignation or Replacement of Auditors — within 10 days following the date on which the Company’s auditors resign or the Company elects to change auditors, as the case may be, notification thereof, together with such further information as the Required Holders may request;

    (g)    Debt Rating — promptly following a Responsible Officer becoming aware of the occurrence thereof, notice of any downward change in the Debt Rating for the Notes (to the extent such Debt Rating is not generally available to the public); and

    (h)    Requested Information — with reasonable promptness, such other data and information relating to the business, operations, affairs, financial condition, assets or properties of the Company or any of its Subsidiaries (including, but without limitation, actual copies of the Company’s Form 10-Q and Form 10-K) or relating to the ability of the Company to perform its obligations hereunder and under the Notes as from time to time may be reasonably requested by any such Purchaser or holder of a Note.

-14-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

    Section 7.2.    Officer’s Certificate. Each set of financial statements delivered to a Purchaser or a holder of a Note pursuant to Section 7.1(a) or Section 7.1(b) shall be accompanied by a certificate of a Senior Financial Officer:

    (a)    Covenant Compliance — setting forth the information from such financial statements that is required in order to establish whether the Company was in compliance with the requirements of Sections 10.3, 10.6, or 10.7 during the quarterly or annual period covered by the financial statements then being furnished, (including with respect to each such provision that involves mathematical calculations, the information from such financial statements that is required to perform such calculations) and detailed calculations of the maximum or minimum amount, ratio or percentage, as the case may be, permissible under the terms of such Section, and the calculation of the amount, ratio or percentage then in existence. In the event that the Company or any Subsidiary has made an election to measure any financial liability using fair value (which election is being disregarded for purposes of determining compliance with this Agreement pursuant to Section 22.2) as to the period covered by any such financial statement, such Senior Financial Officer’s certificate as to such period shall include a reconciliation from GAAP with respect to such election;

    (b)    Event of Default — certifying that such Senior Financial Officer has reviewed the relevant terms hereof and has made, or caused to be made, under his or her supervision, a review of the transactions and conditions of the Company and its Subsidiaries from the beginning of the quarterly or annual period covered by the financial statements then being furnished to the date of the certificate and that such review shall not have disclosed the existence during such period of any condition or event that constitutes a Default or an Event of Default or, if any such condition or event existed or exists, specifying the nature and period of existence thereof and what action the Company shall have taken or proposes to take with respect thereto; and

    (c)    Guarantors – setting forth a list of all Persons that are Guarantors and certifying that each Person that is required to be a Guarantor pursuant to Section 9.7 is a Guarantor, in each case, as of the date of such certificate of Senior Financial Officer.

    Section 7.3.    Visitation. The Company shall permit the representatives of each Purchaser and each holder of a Note that is an Institutional Investor:

    (a)    No Default — if no Default or Event of Default then exists, at the expense of such Purchaser or such holder and upon reasonable prior notice to the Company, to visit the principal executive office of the Company, to discuss the affairs, finances and accounts of the Company and its Subsidiaries with the Company’s officers, and (with the consent of the Company, which consent will not be unreasonably withheld) its independent public accountants, and (with the consent of the Company, which consent will not be unreasonably withheld) to visit the other offices and properties of the Company and each Subsidiary, all at such reasonable times and as often as may be reasonably requested in writing; and

-15-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

    (b)    Default — if a Default or Event of Default then exists, at the expense of the Company, to visit and inspect any of the offices or properties of the Company or any Subsidiary, to examine all their respective books of account, records, reports and other papers, to make copies and extracts therefrom, and to discuss their respective affairs, finances and accounts with their respective officers and independent public accountants (and by this provision the Company authorizes said accountants to discuss the affairs, finances and accounts of the Company and its Subsidiaries), all at such times and as often as may be requested.

    Section 7.4.    Electronic Delivery. Financial statements, opinions of independent certified public accountants, other information and Officer’s Certificates that are required to be delivered by the Company pursuant to Sections 7.1(a), (b), (c), (d), (e), (f), or (g) and Section 7.2 shall be deemed to have been delivered if the Company satisfies any of the following requirements with respect thereto:

    (a)    such financial statements satisfying the requirements of Section 7.1(a) or (b) and related Officer’s Certificate satisfying the requirements of Section 7.2 and any other information required under Section 7.1(c) are delivered to each Purchaser and holder of a Note by e-mail at the e-mail address set forth in such holder’s Purchaser Schedule or as communicated from time to time in a separate writing delivered to the Company;

    (b)    the Company shall have timely filed a Form 10–Q or Form 10–K, satisfying the requirements of Section 7.1(a) or Section 7.1(b), as the case may be, with the SEC on EDGAR and shall have made such form and the related Officer’s Certificate satisfying the requirements of Section 7.2 available on the Company’s home page on the internet, if any;

    (c)    such financial statements satisfying the requirements of Section 7.1(a) or Section 7.1(b) and related Officer’s Certificate(s) satisfying the requirements of Section 7.2 and any other information required under Section 7.1(c), (d), (e), (f), or (g) are timely posted by or on behalf of the Company on Intralinks or on any other similar website to which each holder of Notes has free access; or

    (d)    the Company shall have timely filed any of the items referred to in Section 7.1(c) or (f) with the SEC on EDGAR and shall have made such items available on the Company’s home page on the internet or on Intralinks or on any other similar website to which each holder of Notes has free access;

provided however, that in no case shall access to such financial statements, other information and Officer’s Certificates be conditioned upon any waiver or other agreement or consent (other than confidentiality provisions consistent with Section 20 of this Agreement); provided further, that in the case of any of clauses (b), (c) or (d), the Company shall have given each holder of a Note prior written notice, which may be by e-mail or in accordance with Section 18, of such posting or filing in connection with each delivery, and provided further, that upon request of any holder to receive paper copies of such forms, financial statements, other information and Officer’s

-16-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

Certificates or to receive them by e-mail, the Company will promptly e-mail them or deliver such paper copies, as the case may be, to such holder.

Section 8.    Payment and Prepayment of the Notes.

    Section 8.1.    Maturity.

As provided therein, the entire unpaid principal balance of the Series A Notes and the Series B Notes shall be due and payable on the Series A Maturity Date or the Series B Maturity Date, as applicable.

    Section 8.2.    Optional Prepayments with and without Make-Whole Amount. (a) Subject to Section 8.2(c), at any time prior to April 6, 2041, the Company may, at its option, upon notice as provided below, prepay all, or from time to time any part of, the Series A Notes, in an amount not less than 5% of the aggregate principal amount of the Series A Notes then outstanding in the case of a partial prepayment, at 100% of the principal amount so prepaid, together with interest accrued thereon to the date of such prepayment, plus the Make-Whole Amount determined for the prepayment date with respect to such principal amount. On and after April 6, 2041, the Company may, at its option, upon notice as provided below, prepay at any time all the Series A Notes, at 100% of the principal amount so prepaid, together with interest accrued thereon to the date of such prepayment, but without payment of the Make-Whole Amount.

    (b)     Subject to Section 8.2(c), at any time prior to September 28, 2053, the Company may, at its option, upon notice as provided below, prepay all, or from time to time any part of, the Series B Notes, in an amount not less than 5% of the aggregate principal amount of the Series B Notes then outstanding in the case of a partial prepayment, at 100% of the principal amount so prepaid, together with interest accrued thereon to the date of such prepayment, plus the Make-Whole Amount determined for the prepayment date with respect to such principal amount. On and after September 28, 2053, the Company may, at its option, upon notice as provided below, prepay at any time all the Series B Notes, at 100% of the principal amount so prepaid, together with interest accrued thereon to the date of such prepayment, but without payment of the Make-Whole Amount.

    (c) With respect to Sections 8.2(a) and 8.2(b) above, if a Default or an Event of Default has occurred and is continuing at the time such notice is provided or on the prepayment date or if a Default or an Event of Default would result from the making of such prepayment, such prepayment shall be pro rata to the holders of all Notes then outstanding.

    (d) The Company will give each holder of Notes of such series written notice of each optional prepayment under this Section 8.2 not less than ten (10) days and not more than sixty (60) days prior to the date fixed for such prepayment unless the Company and the Required Holders of the series to be repaid agree to another time period pursuant to Section 17. Each such notice shall specify such date (which shall be a Business Day), the aggregate principal amount of the Notes of such series to be prepaid on such date, the principal amount of each Note of such series held by such holder to be prepaid (determined in accordance with Section 8.3), and the

-17-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

interest to be paid on the prepayment date with respect to such principal amount being prepaid, and, if applicable, shall be accompanied by a certificate of a Senior Financial Officer as to the estimated Make-Whole Amount due with respect to such series of Notes to be prepaid in connection with such prepayment (calculated as if the date of such notice were the date of the prepayment), setting forth the details of such computation. If applicable, two (2) Business Days prior to such prepayment, the Company shall deliver to each holder of Notes of such series a certificate of a Senior Financial Officer specifying the calculation of such Make-Whole Amount as of the specified prepayment date.

    Section 8.3.    Allocation of Partial Prepayments. In the case of each partial prepayment of the Notes of a series pursuant to Section 8.2, the principal amount of the Notes of such series to be prepaid shall be allocated among all of the Notes of such series at the time outstanding in proportion, as nearly as practicable, to the respective unpaid principal amounts thereof not theretofore called for prepayment, provided that if a Default or an Event of Default has occurred and is continuing at the time such notice pursuant to Section 8.2(d) is provided or on the prepayment date or if a Default or an Event of Default would result from the making of such prepayment, such prepayment shall be pro rata to the holders of all Notes then outstanding. In the case of any purchase or prepayment of the Notes pursuant to Section 8.5 or Section 8.7, the principal amount of the Notes to be purchased or prepaid shall be allocated among all of the Notes of the holders who have accepted such offer of purchase or prepayment.

    Section 8.4.    Maturity; Surrender, Etc.     In the case of each prepayment of Notes pursuant to this Section 8, the principal amount of each Note to be prepaid shall mature and become due and payable on the date fixed for such prepayment, together with interest on such principal amount accrued to such date and the applicable Make-Whole Amount, if any. From and after such date, unless the Company shall fail to pay such principal amount when so due and payable, together with the interest and Make-Whole Amount, if any, as aforesaid, interest on such principal amount shall cease to accrue. Any Note paid or prepaid in full shall be surrendered to the Company and cancelled and shall not be reissued, and no Note shall be issued in lieu of any prepaid principal amount of any Note.

    Section 8.5.    Purchase of Notes. The Company will not and will not permit any Affiliate to purchase, redeem, prepay or otherwise acquire, directly or indirectly, any of the outstanding Notes of any series except (a) upon the payment or prepayment of the Notes of such series in accordance with the terms of this Agreement and the applicable Notes or (b) pursuant to a written offer to purchase outstanding Notes of such series made by the Company or an Affiliate pro rata to the holders of the Notes of such series upon the same terms and conditions, provided, that if and so long as any Default or Event of Default exists, such written offer shall be made pro rata to the holders of all Notes of all series outstanding upon the same terms and conditions. Any such offer shall provide each holder with sufficient information to enable it to make an informed decision with respect to such offer, and shall remain open for at least 10 Business Days. If the holders of more than 35% of the principal amount of the Notes of a series then outstanding accept such offer, the Company shall promptly notify the remaining holders of such fact and the expiration date for the acceptance by holders of Notes of such series shall be extended by the number of days necessary to give each such remaining holder at least 5 Business Days from its receipt of such notice to accept such offer. A failure by a holder of Notes to

-18-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

respond to an offer to purchase pursuant to subpart (b) of this Section 8.5 shall be deemed to constitute a rejection of such offer by such holder. The Company will promptly cancel all Notes acquired by it or any Affiliate pursuant to any payment, prepayment or purchase of Notes pursuant to this Agreement and no Notes of such series may be issued in substitution or exchange for any such Notes.

    Section 8.6.    Make-Whole Amount.

The term “Make-Whole Amount” means, with respect to any Note, an amount equal to the excess, if any, of the Discounted Value of the Remaining Scheduled Payments with respect to the Called Principal of such Note over the amount of such Called Principal, provided that the Make-Whole Amount may in no event be less than zero. For the purposes of determining the Make-Whole Amount, the following terms have the following meanings:

“Called Principal” means, with respect to any Note, the principal of such Note that is to be prepaid pursuant to Section 8.2 or has become or is declared to be immediately due and payable pursuant to Section 12.1, as the context requires.

“Discounted Value” means, with respect to the Called Principal of any Note, the amount obtained by discounting all Remaining Scheduled Payments with respect to such Called Principal from their respective scheduled due dates to the Settlement Date with respect to such Called Principal, in accordance with accepted financial practice and at a discount factor (applied on the same periodic basis as that on which interest on the Notes is payable) equal to the Reinvestment Yield with respect to such Called Principal.

“Reinvestment Yield” means, with respect to the Called Principal of any Note, the sum of (a) 0.50% plus (b) the yield to maturity implied by the “Ask Yield(s)” reported as of 10:00 a.m. (New York City time) on the second Business Day preceding the Settlement Date with respect to such Called Principal, on the display designated as “Page PX1” (or such other display as may replace Page PX1) on Bloomberg Financial Markets for the most recently issued actively traded on-the-run U.S. Treasury securities (“Reported”) having a maturity equal to the Remaining Average Life of such Called Principal as of such Settlement Date. If there are no such U.S. Treasury securities Reported having a maturity equal to such Remaining Average Life, then such implied yield to maturity will be determined by (i) converting U.S. Treasury bill quotations to bond equivalent yields in accordance with accepted financial practice and (ii) interpolating linearly between the “Ask Yields” Reported for the applicable most recently issued actively traded on-the-run U.S. Treasury securities with the maturities (1) closest to and greater than such Remaining Average Life and (2) closest to and less than such Remaining Average Life. The Reinvestment Yield shall be rounded to the number of decimal places as appears in the interest rate of the applicable Note.

If such yields are not Reported or the yields Reported as of such time are not ascertainable (including by way of interpolation), then “Reinvestment Yield” means, with respect to the Called Principal of any Note, the sum of (x) 0.50% plus (y) the yield to maturity implied by the U.S. Treasury constant maturity yields reported, for the latest day for which such yields have been so reported as of the second Business Day preceding the Settlement Date with

-19-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

respect to such Called Principal, in Federal Reserve Statistical Release H.15 (or any comparable successor publication) for the U.S. Treasury constant maturity having a term equal to the Remaining Average Life of such Called Principal as of such Settlement Date. If there is no such U.S. Treasury constant maturity having a term equal to such Remaining Average Life, such implied yield to maturity will be determined by interpolating linearly between (1) the U.S. Treasury constant maturity so reported with the term closest to and greater than such Remaining Average Life and (2) the U.S. Treasury constant maturity so reported with the term closest to and less than such Remaining Average Life. The Reinvestment Yield shall be rounded to the number of decimal places as appears in the interest rate of the applicable Note.

“Remaining Average Life” means, with respect to any Called Principal, the number of years obtained by dividing (i) such Called Principal into (ii) the sum of the products obtained by multiplying (a) the principal component of each Remaining Scheduled Payment with respect to such Called Principal by (b) the number of years, computed on the basis of a 360-day year comprised of twelve 30-day months and calculated to two decimal places, that will elapse between the Settlement Date with respect to such Called Principal and the scheduled due date of such Remaining Scheduled Payment.

“Remaining Scheduled Payments” means, with respect to the Called Principal of any Note, all payments of such Called Principal and interest thereon that would be due after the Settlement Date with respect to such Called Principal if no payment of such Called Principal were made prior to its scheduled due date, provided that if such Settlement Date is not a date on which interest payments are due to be made under the Notes, then the amount of the next succeeding scheduled interest payment will be reduced by the amount of interest accrued to such Settlement Date and required to be paid on such Settlement Date pursuant to Section 8.2 or Section 12.1.

“Settlement Date” means, with respect to the Called Principal of any Note, the date on which such Called Principal is to be prepaid pursuant to Section 8.2 or has become or is declared to be immediately due and payable pursuant to Section 12.1, as the context requires.

    Section 8.7.    Change of Control. (a) Notice of Change of Control. The Company will, within 15 Business Days after any Responsible Officer has knowledge of the occurrence of any Change of Control, give written notice of such Change of Control to each holder of Notes (determined as of the date of such notice). Such notice shall contain and constitute an offer to prepay Notes as described in subparagraph (b) of this Section 8.7 and shall be accompanied by the certificate described in subparagraph (e) of this Section 8.7.

    (b)    Offer to Prepay Notes. The offer to prepay Notes contemplated by subparagraph (a) of this Section 8.7 shall be an offer to prepay, in accordance with and subject to this Section 8.7, all, but not less than all, the Notes held by each holder (in this case only, “holder” in respect of any Note registered in the name of a nominee for a disclosed beneficial owner shall mean such beneficial owner) on a date specified in such offer (the “Proposed Prepayment Date”). The Proposed Prepayment Date shall be not less than 20 days and not more than 60 days after the date of such offer (if the Proposed Prepayment Date shall not be

-20-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

specified in such offer, the Proposed Prepayment Date shall be the 45th day after the date of such offer).

    (c)    Acceptance; Rejection. A holder of Notes may accept or reject the offer to prepay made pursuant to this Section 8.7 by causing a notice of such acceptance or rejection to be delivered to the Company at least 5 Business Days prior to the Proposed Prepayment Date. A failure by a holder of Notes to respond to an offer to prepay made pursuant to this Section 8.7, or to accept an offer as to all of the Notes held by such holder, in each case on or before the 5th Business Day preceding the Proposed Prepayment Date, shall be deemed to constitute a rejection of such offer by such holder.

    (d)    Prepayment. Prepayment of the Notes to be prepaid pursuant to this Section 8.7 shall be at 100% of the principal amount of such Notes, together with interest on such Notes accrued to the date of prepayment and without any Make-Whole Amount. The prepayment shall be made on the Proposed Prepayment Date.

    (e)    Officer’s Certificate. Each offer to prepay the Notes pursuant to this Section 8.7 shall be accompanied by a certificate, executed by a Senior Financial Officer of the Company and dated the date of such offer, specifying: (i) the Proposed Prepayment Date; (ii) that such offer is made pursuant to this Section 8.7; (iii) the principal amount of each Note offered to be prepaid; (iv) the interest that would be due on each Note offered to be prepaid, accrued to the Proposed Prepayment Date; and (v) in reasonable detail, the nature and date of the Change of Control.

    (f)    Definition of Change of Control. “Change of Control” means

    (1) an event or series of events by which any “person” or “group” (as such terms are used in Sections 13(d) and 14(d) of the Securities Exchange Act of 1934, but excluding any employee benefit plan of such person or its subsidiaries, and any person or entity acting in its capacity as trustee, agent or other fiduciary or administrator of any such plan) becomes the “beneficial owner” (as defined in Rules 13d-3 and 13d-5 under the Securities Exchange Act of 1934, except that a person or group shall be deemed to have “beneficial ownership” of all securities that such person or group has the right to acquire, whether such right is exercisable immediately or only after the passage of time (such right, an “option right”)), directly or indirectly, of 50% or more of the equity securities of Ameren entitled to vote for members of the board of directors or equivalent governing body of Ameren on a fully-diluted basis (and taking into account all such securities that such person or group has the right to acquire pursuant to any option right); or (2) Ameren shall cease to own, directly or indirectly, at least 75% of the voting capital stock or other equity or voting interests of the Company that is ordinarily entitled, in the absence of contingencies, to vote in the election of the Company’s directors (excluding, for the avoidance of doubt, preferred stock or other Securities of the Company the holders of which may be entitled to vote to elect directors only upon a default or under other limited circumstances specified in such Securities);

-21-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

provided, that the events specified in clause (1) or (2) of this Section 8.7(f) shall not constitute a “Change of Control” if, on the day of the occurrence of such event and at all times during the period of 90 consecutive days thereafter (the “Ratings Period”), long-term unsecured, unenhanced debt securities of the Company shall maintain an Investment Grade Rating by at least one Acceptable Rating Agency or, if more than one Acceptable Rating Agency shall rate such debt securities during such Ratings Period, each such Acceptable Rating Agency.

    Section 8.8.    Payments Due on Non-Business Days. Anything in this Agreement or the Notes to the contrary notwithstanding, (x) except as set forth in clause (y), any payment of interest on any Note that is due on a date that is not a Business Day shall be made on the next succeeding Business Day without including the additional days elapsed in the computation of the interest payable on such next succeeding Business Day; and (y) any payment of principal of or Make-Whole Amount on any Note (including principal due on the Series A Maturity Date or the Series B Maturity Date of such Note, as applicable) that is due on a date that is not a Business Day shall be made on the next succeeding Business Day and shall include the additional days elapsed in the computation of interest payable on such next succeeding Business Day.

Section 9.    Affirmative Covenants.

From the date of this Agreement until the Second Closing and thereafter, so long as any of the Notes are outstanding, the Company covenants that:

    Section 9.1.    Compliance with Laws. Without limiting Section 10.4, the Company will, and will cause each of its Subsidiaries to, comply with all laws, ordinances or governmental rules or regulations to which each of them is subject (including ERISA, Environmental Laws, the USA PATRIOT Act and the other laws and regulations that are referred to in Section 5.16) and will obtain and maintain in effect all licenses, certificates, permits, franchises and other governmental authorizations necessary to the ownership of their respective properties or to the conduct of their respective businesses, in each case to the extent necessary to ensure that non-compliance with such laws, ordinances or governmental rules or regulations or failures to obtain or maintain in effect such licenses, certificates, permits, franchises and other governmental authorizations would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

    Section 9.2.    Insurance. The Company will, and will cause each of its Subsidiaries to, maintain, with financially sound and reputable insurers, insurance with respect to their respective properties and businesses against such casualties and contingencies, of such types, on such terms and in such amounts (including deductibles, co-insurance and self-insurance, if adequate reserves are maintained with respect thereto) as is customary in the case of entities of established reputations engaged in the same or a similar business and similarly situated, except in each case to the extent that any non-compliance with the terms of this Section 9.2 would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

    Section 9.3.    Maintenance of Properties. The Company will, and will cause each of its Subsidiaries to, maintain and keep, or cause to be maintained and kept, their respective properties in good repair, working order and condition (other than ordinary wear and tear), so that the

-22-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

business carried on in connection therewith may be properly conducted at all times, provided that this Section 9.3 shall not prevent the Company or any Subsidiary from discontinuing the operation and the maintenance of any of its properties if such discontinuance is desirable in the conduct of its business and the Company has concluded that such discontinuance would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

    Section 9.4.    Payment of Taxes. The Company will, and will cause each of its Subsidiaries to, file all tax returns required to be filed in any jurisdiction and to pay and discharge all taxes shown to be due and payable on such returns and all other taxes, assessments, governmental charges or levies imposed on them or any of their properties, assets, income or franchises, to the extent the same have become due and payable and before they have become delinquent, provided that neither the Company nor any Subsidiary need pay any such tax, assessment, charge or levy if (i) the amount, applicability or validity thereof is contested by the Company or such Subsidiary on a timely basis in good faith and in appropriate proceedings, and the Company or a Subsidiary has established adequate reserves therefor in accordance with GAAP on the books of the Company or such Subsidiary or (ii) the non-filing of all such returns or nonpayment of all such taxes, assessments, charges and levies would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

    Section 9.5.    Corporate Existence, Etc. Subject to Section 10.2, the Company will at all times preserve and keep its corporate or company existence in full force and effect. Subject to Sections 10.2 and 10.3, the Company will at all times preserve and keep in full force and effect the corporate or company existence of each of its Subsidiaries (unless merged into the Company or a Wholly-Owned Subsidiary) and all Material rights and franchises of the Company and its Subsidiaries unless, in the good faith judgment of the Company, the termination of or failure to preserve and keep in full force and effect such corporate or company existence, right or franchise would not, individually or in the aggregate, have a Material Adverse Effect.

        Section 9.6.    Books and Records. The Company will, and will cause each of its Subsidiaries to, maintain proper books of record and account in conformity with GAAP in all Material respects and all applicable requirements of any Governmental Authority having legal or regulatory jurisdiction over the Company or such Subsidiary, as the case may be. The Company will, and will cause each of its Subsidiaries to, keep books, records and accounts which, in reasonable detail, accurately reflect all transactions and dispositions of assets. The Company and its Subsidiaries have devised a system of internal accounting controls sufficient to provide reasonable assurances that their respective books, records, and accounts accurately reflect all transactions and dispositions of assets and the Company will, and will cause each of its Subsidiaries to, continue to maintain such system.

    Section 9.7.    Guarantors. (a) The Company will cause any Person that guarantees or otherwise becomes liable at any time, whether as a borrower or an additional or co-borrower or otherwise, for any Indebtedness of the Company under any Material Credit Facility to concurrently therewith:

    (i)    enter into an agreement in form and substance satisfactory to the Required Holders providing for the guaranty by such Person, on a joint and several basis with all

-23-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

other such Persons, of (x) the prompt payment in full when due of all amounts payable by the Company pursuant to the Notes (whether for principal, interest, Make-Whole Amount or otherwise) and this Agreement, including all indemnities, fees and expenses payable by the Company thereunder and (y) the prompt, full and faithful performance, observance and discharge by the Company of each and every covenant, agreement, undertaking and provision required pursuant to the Notes or this Agreement to be performed, observed or discharged by it (a “Guaranty Agreement”); and

    (ii)    deliver the following to each holder of a Note:

    (A)    an executed counterpart of such Guaranty Agreement;

    (B)    a certificate signed by an authorized responsible officer of such Person containing representations and warranties on behalf of such Person to the same effect, mutatis mutandis, as those contained in Sections 5.1, 5.2, 5.6, and 5.7 of this Agreement (but with respect to such Person and such Guaranty Agreement rather than the Company);

    (C)    all documents as may be reasonably requested by the Required Holders to evidence the due organization, continuing existence and, where applicable, good standing of such Person and the due authorization by all requisite action on the part of such Person of the execution and delivery of such Guaranty Agreement and the performance by such Person of its obligations thereunder; and

    (D)    an opinion of counsel reasonably satisfactory to the Required Holders covering such matters relating to such Person and such Guaranty Agreement as the Required Holders may reasonably request.

    (b)    At the election of the Company and by written notice to each holder of Notes, any Guarantor may be discharged from all of its obligations and liabilities under its Guaranty Agreement and shall be automatically released from its obligations thereunder without the need for the execution or delivery of any other document by the holders, provided that (i) if such Guarantor is or was a guarantor or is or was otherwise liable for or in respect of any Material Credit Facility, then such Guarantor has been released and discharged (or will be released and discharged concurrently with the release of such Guarantor under its Guaranty Agreement) under such Material Credit Facility, (ii) at the time of, and after giving effect to, such release and discharge, no Default or Event of Default shall be existing, (iii) no amount is then due and payable under such Guaranty Agreement, (iv) if in connection with such Guarantor being released and discharged under any Material Credit Facility, any fee or other form of consideration is given to any holder of Indebtedness under such Material Credit Facility for such release, the holders of the Notes shall receive equivalent consideration substantially concurrently therewith and (v) each holder shall have received a certificate of a Responsible Officer certifying as to the matters set forth in clauses (i) through (iv). In the event of any such release, for purposes of Section 10.7, all Indebtedness of such Person shall be deemed to have been incurred by such Person concurrently with such release.

-24-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

    Section 9.8.    Notes to Rank Pari Passu. The obligations of the Company under this Agreement and the Notes rank pari passu in right of payment with all other unsubordinated unsecured Indebtedness (actual or contingent) of the Company, including, without limitation, all Material Credit Facilities.

    Section 9.9.    Energy Regulatory Status. The Company will take or cause to be taken all necessary or appropriate actions to maintain in full force and effect each regulatory approval required to construct, operate, and maintain its properties (including its transmission facilities) and to conduct its business of transmitting electricity.

    Section 9.10.    Maintenance of Rating on the Notes. (a) The Company shall at all times maintain a Debt Rating for the Notes from one Acceptable Rating Agency, provided that, if the Acceptable Rating Agency providing the Debt Rating for the Notes withdraws or terminates such rating (such that no Acceptable Rating Agency is providing a Debt Rating for the Notes), the Company shall have 90 days from the withdrawal or termination of such rating to obtain a Debt Rating from another Acceptable Rating Agency.

(b) At any time that the Debt Rating maintained pursuant to clause (a) above is not generally available to the public, the Company will provide to each holder of a Note (x) at least annually (on or before each anniversary of the date of the First Closing) and (y) promptly upon any change in such Debt Rating, an updated Private Rating Letter evidencing such Debt Rating and an updated Private Rating Rationale Report with respect to such Debt Rating.  In addition to the foregoing information and any information specifically required to be included in any Private Rating Letter or Private Rating Rationale Report (as set forth in the respective definitions thereof), if the SVO or any other Governmental Authority having jurisdiction over any holder of any Notes from time to time requires any additional information with respect to the Debt Rating of the Notes, the Company shall use commercially reasonable efforts to procure such information from the Acceptable Rating Agency.

Section 10.    Negative Covenants.

From the date of this Agreement until the Second Closing and thereafter, so long as any of the Notes are outstanding, the Company covenants that:

    Section 10.1.    Transactions with Affiliates. Except as otherwise permitted by this Agreement, the Company will not, and will not permit any Significant Subsidiary to, enter into directly or indirectly any Material transaction or Material group of related transactions (including the purchase, lease, sale or exchange of properties of any kind or the rendering of any service) with any Affiliate (other than the Company or another Subsidiary), except (a) pursuant to the reasonable requirements of the Company’s or such Significant Subsidiary’s business and upon fair and reasonable terms no less favorable to the Company or such Significant Subsidiary than would be obtainable in a comparable arm’s-length transaction with a Person not an Affiliate, (b) any transaction that is in compliance with applicable laws and regulations of the Federal Energy Regulatory Commission or any other regulatory authority with jurisdiction over the Company or its Affiliates or is authorized by a tariff or rate schedule which has been approved by a Governmental Authority, (c) any transaction that is otherwise permitted under Section 10.2, or

-25-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

(d) transactions pursuant to any contract in effect on the date of this Agreement, to the extent that (i) the terms of the contract are arm’s-length or customary for similarly situated companies or (ii) the contract has been approved by, accepted by, or filed with a regulatory authority with jurisdiction over the Company, as such contract may be amended, extended or replaced from time to time so long as such contract as so amended, extended or replaced is, taken as a whole, not materially less favorable to the Company or such Significant Subsidiary, as the case may be, than under the contracts between the Company and its Affiliates in effect on the date of this Agreement.

    Section 10.2.    Merger, Consolidation, Etc. The Company will not, and will not permit any Subsidiary to, consolidate with or merge with any other Person or convey, transfer or lease all or substantially all of its assets in a single transaction or series of transactions to any Person unless:

    (a)    in the case of any such transaction involving the Company, the successor formed by such consolidation or the survivor of such merger or the Person that acquires by conveyance, transfer or lease all or substantially all of the assets of the Company as an entirety, as the case may be, shall be a solvent corporation or limited liability company organized and existing under the laws of the United States or any state thereof (including the District of Columbia), and, if the Company is not such corporation or limited liability company, (i) such corporation or limited liability company shall have executed and delivered to each holder of any Notes its assumption of the due and punctual performance and observance of each covenant and condition of this Agreement and the Notes and (ii) such corporation or limited liability company shall have caused to be delivered to each holder of any Notes an opinion of nationally recognized independent counsel, or other independent counsel reasonably satisfactory to the Required Holders, to the effect that all agreements or instruments effecting such assumption are enforceable in accordance with their terms and comply with the terms hereof;

    (b)    in the case of any such transaction involving a Subsidiary, the successor formed by such consolidation or the survivor of such merger or the Person that acquires by conveyance, transfer or lease all or substantially all of the assets of such Subsidiary as an entirety, as the case may be, shall be (1) the Company, (2) another Subsidiary, or (3) any other Person so long as the transaction is treated as a disposition of all of the assets of such Subsidiary for purposes of Section 10.3 and, based on such characterization, would be permitted pursuant to Section 10.3;

    (c)    each Guarantor under any Guaranty Agreement that is outstanding at the time such transaction or each transaction in such a series of transactions occurs reaffirms its obligations under such Guaranty Agreement in writing at such time pursuant to documentation that is reasonably acceptable to the Required Holders; and

    (d)    immediately before and immediately after giving effect to such transaction or each transaction in any such series of transactions, no Default or Event of Default shall have occurred and be continuing.

-26-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

No such conveyance, transfer or lease of substantially all of the assets of the Company or any Guarantor shall have the effect of releasing the Company or such Guarantor, as the case may be, or any successor corporation or limited liability company that shall theretofore have become such in the manner prescribed in this Section 10.2, from its liability under (x) this Agreement or the Notes (in the case of the Company) or (y) the Guaranty Agreement (in the case of any Guarantor), unless, in the case of the conveyance, transfer or lease of substantially all of the assets of a Guarantor, such Guarantor is released from its Guaranty Agreement in accordance with Section 9.7(b) in connection with or immediately following such conveyance, transfer or lease.

    Section 10.3.    Sale of Assets. The Company will not and will not permit any Subsidiary to, sell, lease or otherwise dispose of any Substantial Part (as defined below) of the assets of the Company and its Subsidiaries; provided, however, that the Company or any Subsidiary may sell, lease or otherwise dispose of assets constituting a Substantial Part of the assets of the Company and its Subsidiaries if such assets are sold in an arm’s length transaction and, at such time and after giving effect thereto, no Default or Event of Default shall have occurred and be continuing and an amount equal to the net proceeds received from such sale, lease or other disposition of that portion of such assets that exceeds the definition of Substantial Part (but not less than that portion of such assets that exceeds the definition of Substantial Part) shall be used within 365 days of such sale, lease or disposition, in any combination:

    (1)    to acquire productive assets used or useful in carrying on the business of the Company and its Subsidiaries, provided, that such assets are acquired in one or more arm’s length transactions or in one or more non-arm’s length transactions permitted by Section 10.1; and/or

    (2)    to prepay or retire Senior Debt of the Company and its Subsidiaries, provided that (i) the Company shall offer to prepay each outstanding Note in a principal amount which equals the Ratable Portion for such Note, and (ii) any such prepayment of the Notes shall be made at 100% of the principal amount thereof, together with accrued interest thereon to the date of such prepayment, but without the payment of the Make-Whole Amount. Any offer of prepayment of the Notes pursuant to this Section 10.3 shall be given to each holder of the Notes by written notice that shall be delivered not less than thirty (30) days and not more than sixty (60) days prior to the proposed prepayment date. Each such notice shall state that it is given pursuant to this Section 10.3 and that the offer set forth in such notice must be accepted by such holder in writing and shall also set forth (i) the prepayment date, (ii) a description of the circumstances which give rise to the proposed prepayment and (iii) a calculation of the Ratable Portion for such holder’s Notes. Each holder of the Notes which desires to have its Notes prepaid shall notify the Company in writing delivered not less than five (5) Business Days prior to the proposed prepayment date of its acceptance of such offer of prepayment. A failure by a holder of Notes to respond to an offer to prepay made pursuant to this Section 10.3, or to accept an offer as to all of the Notes held by such holder, in each case on or before the 5th Business Day preceding the proposed prepayment date, shall be deemed to constitute a rejection of such offer by such holder. Prepayment of Notes pursuant to this Section 10.3 shall be made in accordance with Section 8.2 (but without payment of the Make-Whole Amount).

-27-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

As used in this Section 10.3, a sale, lease or other disposition of assets shall be deemed to be a “Substantial Part” of the assets of the Company and its Subsidiaries if the book value of such assets, when added to the book value of all other assets sold, leased or otherwise disposed of by the Company and its Subsidiaries during the period of 12 consecutive months ending on the date of such sale, lease or other disposition, exceeds 10% of the book value of Consolidated Total Assets, determined as of the end of the fiscal year immediately preceding such sale, lease or other disposition; provided that there shall be excluded from any determination of a “Substantial Part” (i) any sale or disposition of assets in the ordinary course of business of the Company and its Subsidiaries, (ii) any transfer of assets from the Company to any Subsidiary or from any Subsidiary to the Company or a Subsidiary, and (iii) any sale or transfer of property acquired by the Company or any Subsidiary after the date of this Agreement to any Person within 365 days following the acquisition or construction of such property by the Company or any Subsidiary if the Company or a Subsidiary shall concurrently with such sale or transfer, lease such property, as lessee.

    Section 10.4.    Line of Business. The Company will not and will not permit any Subsidiary to engage in any business if, as a result, the principal business in which the Company and its Subsidiaries, taken as a whole, would then be engaged would no longer be the transmission of electricity.

    Section 10.5.    Economic Sanctions, Etc. The Company will not, and will not permit any Controlled Entity to (a) become (including by virtue of being owned or controlled by a Blocked Person), own or control a Blocked Person or (b) directly or indirectly have any investment in or engage in any dealing or transaction (including any investment, dealing or transaction involving the proceeds of the Notes) with any Person if such investment, dealing or transaction (i) would cause any Purchaser or holder or any affiliate of such Purchaser or holder to be in violation of, or subject to sanctions under, any law or regulation applicable to such Purchaser or holder, or (ii) is prohibited by or subject to sanctions under any U.S. Economic Sanctions Laws.

    Section 10.6.    Liens. The Company will not and will not permit any of its Subsidiaries to directly or indirectly create, incur, assume or permit to exist (upon the happening of a contingency or otherwise) any Lien on or with respect to any property or asset (including any document or instrument in respect of goods or accounts receivable) of the Company or any such Subsidiary, whether now owned or held or hereafter acquired, or any income or profits therefrom, or assign or otherwise convey any right to receive income or profits, except:

    (a)    Liens existing on the date of this Agreement and described on Schedule 10.6;

    (b)    Liens for taxes, assessments or other governmental charges which are not yet due and payable or the payment of which is not at the time required by Section 9.4;

    (c)    statutory Liens of landlords and Liens of carriers, warehousemen, mechanics, materialmen and other similar Liens including Liens incident to construction, in each case, securing claims incurred in the ordinary course of business for sums not yet due and payable or (i) the amount, applicability or validity thereof is contested by the

-28-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

Company or such Subsidiary on a timely basis in good faith and in appropriate proceedings, and the Company or a Subsidiary has established adequate reserves therefor in accordance with GAAP on the books of the Company or such Subsidiary or (ii) the nonpayment of all such taxes, assessments, charges, levies and claims could not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect;

    (d)    Liens (other than any Lien imposed by ERISA) incurred or deposits made in the ordinary course of business (i) for salary or wages earned, but not yet payable, or (ii) in connection with workers’ compensation, unemployment insurance and other types of social security or retirement benefits, or (iii) to secure (or to obtain letters of credit that secure) the performance of tenders, statutory obligations, surety, reclamations or appeal bonds, bids, leases (other than Capital Leases), or other obligations, or (iv) to secure (or to obtain letters of credit that secure) obligations to public utilities, municipalities, governmental or other public authorities in connection with the supply of services or utilities to the Company or a Subsidiary, in each case not incurred or made in connection with the borrowing of money, the obtaining of advances or credit or the payment of the deferred purchase price of property;

    (e)    any attachment or judgment Lien, unless the judgment it secures shall not, within 60 days after the entry thereof, have been discharged or execution thereof stayed pending appeal, or shall not have been discharged within 60 days after the expiration of any such stay;

    (f)    Liens consisting of grants by the Company or any of its Subsidiaries of easements, rights of access, leases or rights-of-way in, upon, over and/or across the property or rights-of-way of the Company or its Subsidiaries for the purpose of roads, pipe lines, transmission lines, distribution lines, communication lines, railways, removal of coal or other minerals, water or timber, and other like purposes, or for the joint or common use of real property, rights-of-way, facilities and/or equipment; provided, however, that no such grant shall materially impair the use of the property or rights-of-way for the purposes for which such property or rights-of-way are held by the Company or its Subsidiaries;

    (g)    Liens consisting of minor survey exceptions and the like which do not, in the aggregate, materially detract from the value of such property;

    (h)    Liens consisting of controls, restrictions, obligations, duties and/or other burdens imposed by federal, state, municipal or other law, or by rules, regulations or orders of Governmental Authorities, upon any property of the Company or its Subsidiaries or the ownership, operation or use thereof or upon the Company with respect to any of its property or the operation or use thereof or with respect to any franchise, grant, license, permit or public purpose requirement, or any rights reserved to or otherwise vested in Governmental Authorities to impose any such controls, restrictions, obligations, duties and/or other burdens;

-29-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

    (i)    Liens consisting of rights reserved to or vested in others to take or receive any part of any coal, ore, gas, oil and other minerals, any timber and/or any electric capacity or energy, gas, water, steam and any other products developed, produced, manufactured, generated, purchased or otherwise acquired by the Company or by others on property of the Company or any of its Subsidiaries;

    (j)    Liens on property or assets of any Subsidiary securing Indebtedness owing to the Company or to another Wholly-Owned Subsidiary;

    (k)    any Lien created to secure all or any part of the purchase price, or to secure Indebtedness incurred or assumed to pay all or any part of the purchase price or cost of construction, of property (or any improvement thereof) acquired or constructed by the Company or a Subsidiary after the date of the First Closing, provided that (i) any such Lien shall extend solely to the item or items of such property (or improvement thereon) so acquired or constructed and, if required by the terms of the instrument originally creating such Lien, other property (or improvements thereon) which is an improvement to, replacement for any part of such property, or is acquired for specific use in connection with such acquired or constructed property (or improvement thereof) or which is real property being improved by such acquired or constructed property (or improvement thereon); (ii) the principal amount of the Indebtedness secured by such Lien shall at no time exceed an amount equal to 100% of the lesser of (A) the cost to the Company or such Subsidiary of the property (or improvement thereon) so acquired or constructed and (B) the fair market value (as determined in good faith by the board of directors of the Company) of such property (or improvement thereon) at the time of such acquisition or construction; and (iii) any such Lien shall be created contemporaneously with, or within 365 days after, the acquisition or completion of construction of such property;

    (l)    any Lien existing on property of a Person immediately prior to its being consolidated with or merged into the Company or a Subsidiary or its becoming a Subsidiary, or any Lien existing on any property acquired by the Company or any Subsidiary at the time such property is so acquired (whether or not the Indebtedness secured thereby shall have been assumed), provided that (i) no such Lien shall have been created or assumed in contemplation of such consolidation or merger or such Person's becoming a Subsidiary or such acquisition of property, and, (ii) each such Lien shall extend solely to the item or items of property so acquired and, if required by the terms of the instrument originally creating such Lien, other property which is an improvement to, a replacement for any part of, or is acquired for specific use in connection with such acquired property;

    (m)    any Lien on property or interests in property owned any Person other than the Company or its Subsidiaries in, upon, over and/or across which the Company or its Subsidiaries own any easements, rights of access, leases, rights-of-way, any joint, common or undivided interest, or any other property or interest in property, provided that (1) such Lien shall not extend to the property or interests in property owned by the Company or its Subsidiaries or (2) such Lien shall not materially impair the use of the property or interests in property owned by the Company or its Subsidiaries for the

-30-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

purposes for which such property or interests in property are owned by the Company or its Subsidiaries;

    (n)    any Lien renewing, extending or replacing one or more Liens permitted by subsections (a), (j), (k), (l), (m), and (n), of this Section 10.6, provided that, (i) the principal amount of Indebtedness secured by such Lien(s) immediately prior to such extension, renewal or refunding is not increased or the maturity thereof reduced, (ii) such Lien is not extended to any property other than property permitted to be subject to such Lien(s) by such subsections, and (iii) immediately after such extension, renewal or refunding, no Default or Event of Default would exist; and

    (o)    other Liens securing Indebtedness of the Company or any Subsidiary not otherwise permitted by subsections (a) through (n) of this Section 10.6, provided that Priority Debt shall not at any time exceed the amount permitted by Section 10.7, provided, further, that notwithstanding the foregoing, the Company shall not, and shall not permit any of its Subsidiaries to, secure pursuant to this Section 10.6(o) any Indebtedness outstanding under or pursuant to any Material Credit Facility unless and until the Notes (and any guaranty delivered in connection therewith) shall concurrently be secured equally and ratably with such Indebtedness pursuant to documentation reasonably acceptable to the Required Holders in substance and in form, including an intercreditor agreement and opinions of counsel to the Company and/or any such Subsidiary, as the case may be, from counsel that is reasonably acceptable to the Required Holders.

    Section 10.7.    Financial Covenants. The Company will not at any time permit:

    (a)    Consolidated Debt to exceed 70% of Consolidated Total Capitalization (Consolidated Total Capitalization to be determined as of the end of the most recently ended fiscal quarter of the Company); or

    (b)    Priority Debt to exceed 10% of Consolidated Total Assets (Consolidated Total Assets to be determined as of the end of the most recently ended fiscal quarter of the Company).

Section 11.    Events of Default.

An “Event of Default” shall exist if any of the following conditions or events shall occur and be continuing:

    (a)    the Company defaults in the payment of any principal or Make-Whole Amount, if any, on any Note when the same becomes due and payable, whether at maturity or at a date fixed for prepayment or by declaration or otherwise; or

    (b)    the Company defaults in the payment of any interest on any Note for more than five Business Days after the same becomes due and payable; or

-31-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

    (c)    the Company defaults in the performance of or compliance with any term contained in Section 7.1(d) or Section 10.2; or

    (d)    the Company or any Guarantor defaults in the performance of or compliance with any term contained herein (other than those referred to in Sections 11(a), (b), and (c)) or in any Guaranty Agreement and such default is not remedied within 30 days after the earlier of (i) a Responsible Officer obtaining actual knowledge of such default and (ii) the Company receiving written notice of such default from any holder of a Note (any such written notice to be identified as a “notice of default” and to refer specifically to this Section 11(d)); or

    (e)    (i) any representation or warranty made in writing by or on behalf of the Company or by any officer of the Company in this Agreement or any writing furnished in connection with the transactions contemplated hereby proves to have been false or incorrect in any material respect on the date as of which made, or (ii) any representation or warranty made in writing by or on behalf of any Guarantor or by any officer of such Guarantor in any Guaranty Agreement or any writing furnished in connection with such Guaranty Agreement proves to have been false or incorrect in any material respect on the date as of which made; or

    (f)    (i) the Company or any Significant Subsidiary is in default (as principal or as guarantor or other surety) in the payment of any principal of or premium or make-whole amount or interest on any Indebtedness (other than the Notes) that is outstanding in an aggregate principal amount of at least the Threshold Amount beyond any period of grace provided with respect thereto, or (ii) the Company or any Significant Subsidiary is in default in the performance of or compliance with any term of any evidence of any Indebtedness in an aggregate outstanding principal amount of at least the Threshold Amount or of any mortgage, indenture or other agreement relating thereto or any other condition exists, and as a consequence of such default or condition, such Indebtedness has become or has been declared due and payable before its stated maturity or before its regularly scheduled dates of payment; or

    (g)    the Company or any Significant Subsidiary (i) is generally not paying, or admits in writing its inability to pay, its debts as they become due, (ii) files, or consents by answer or otherwise to the filing against it of, a petition for relief or reorganization or arrangement or any other petition in bankruptcy, for liquidation or to take advantage of any bankruptcy, insolvency, reorganization, moratorium or other similar law of any jurisdiction, (iii) makes an assignment for the benefit of its creditors, (iv) consents to the appointment of a custodian, receiver, trustee or other officer with similar powers with respect to it or with respect to any substantial part of its property, (v) is adjudicated as insolvent or to be liquidated, or (vi) takes corporate action for the purpose of any of the foregoing; or

    (h)    a court or other Governmental Authority of competent jurisdiction enters an order appointing, without consent by the Company or any of its Significant Subsidiaries, a custodian, receiver, trustee or other officer with similar powers with

-32-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

respect to it or with respect to any substantial part of its property, or constituting an order for relief or approving a petition for relief or reorganization or any other petition in bankruptcy or for liquidation or to take advantage of any bankruptcy or insolvency law of any jurisdiction, or ordering the dissolution, winding-up or liquidation of the Company or any of its Significant Subsidiaries, or any such petition shall be filed against the Company or any of its Significant Subsidiaries and such petition shall not be dismissed within 60 days; or

    (i)    any event occurs with respect to the Company or any Significant Subsidiary which under the laws of any jurisdiction is analogous to any of the events described in Section 11(g) or Section 11(h), provided that the applicable grace period, if any, which shall apply shall be the one applicable to the relevant proceeding which most closely corresponds to the proceeding described in Section 11(g) or Section 11(h); or

    (j)    one or more final judgments or orders for the payment of money aggregating in excess of the Threshold Amount, including any such final order enforcing a binding arbitration decision, are rendered against one or more of the Company and its Significant Subsidiaries and which judgments are not, within 60 days after entry thereof, bonded, discharged or stayed pending appeal, or are not discharged within 60 days after the expiration of such stay; or

    (k)    if (i) any Plan shall fail to satisfy the minimum funding standards of ERISA or the Code for any plan year or part thereof or a waiver of such standards or extension of any amortization period is sought or granted under section 412 of the Code, (ii) a notice of intent to terminate any Plan shall have been or is reasonably expected to be filed with the PBGC or the PBGC shall have instituted proceedings under ERISA section 4042 to terminate or appoint a trustee to administer any Plan or the PBGC shall have notified the Company or any ERISA Affiliate that a Plan may become a subject of any such proceedings, (iii) there is any “amount of unfunded benefit liabilities” (within the meaning of section 4001(a)(18) of ERISA) in excess of the Threshold Amount under one or more Plans, determined in accordance with Title IV of ERISA, (iv) the aggregate present value of accrued benefit liabilities under all funded Non-U.S. Plans exceeds the aggregate current value of the assets of such Non-U.S. Plans allocable to such liabilities, (v) the Company or any ERISA Affiliate shall have incurred or is reasonably expected to incur any liability pursuant to Title I of ERISA or Title IV of ERISA or the penalty or excise tax provisions of the Code relating to employee benefit plans, (vi) the Company or any ERISA Affiliate withdraws from any Multiemployer Plan, (vii) the Company or any Subsidiary establishes or amends any employee welfare benefit plan that provides post-employment welfare benefits in a manner that would increase the liability of the Company or any Subsidiary thereunder, (viii) the Company or any Subsidiary fails to administer or maintain a Non-U.S. Plan in compliance with the requirements of any and all applicable laws, statutes, rules, regulations or court orders or any Non-U.S. Plan is involuntarily terminated or wound up, or (ix) the Company or any Subsidiary becomes subject to the imposition of a financial penalty (which for this purpose shall mean any tax, penalty or other liability, whether by way of indemnity or otherwise) with respect to one or more Non-U.S. Plans; and any such event or events described in clauses (i)

-33-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

through (ix) above, either individually or together with any other such event or events, would reasonably be expected to have a Material Adverse Effect. As used in this Section 11(k), the terms “employee benefit plan” and “employee welfare benefit plan” shall have the respective meanings assigned to such terms in section 3 of ERISA; or

    (l)    any Guaranty Agreement shall cease to be in full force and effect, any Guarantor or any Person acting on behalf of any Guarantor shall contest in any manner the validity, binding nature or enforceability of any Guaranty Agreement, or the obligations of any Guarantor under any Guaranty Agreement are not or cease to be legal, valid, binding and enforceable in accordance with the terms of such Guaranty Agreement.

Section 12.    Remedies on Default, Etc.

    Section 12.1.    Acceleration. (a) If an Event of Default with respect to the Company described in Section 11(g), (h), or (i) (other than an Event of Default described in clause (i) of Section 11(g) or described in clause (vi) of Section 11(g) by virtue of the fact that such clause encompasses clause (i) of Section 11(g)) has occurred, all the Notes then outstanding shall automatically become immediately due and payable.

    (b)    If any other Event of Default has occurred and is continuing, the Required Holders may at any time at its or their option, by notice or notices to the Company, declare all the Notes then outstanding to be immediately due and payable.

    (c)    If any Event of Default described in Section 11(a) or (b) has occurred and is continuing, any holder or holders of Notes at the time outstanding affected by such Event of Default may at any time, at its or their option, by notice or notices to the Company, declare all the Notes held by it or them to be immediately due and payable.

Upon any Notes becoming due and payable under this Section 12.1, whether automatically or by declaration, such Notes will forthwith mature and the entire unpaid principal amount of such Notes, plus (x) all accrued and unpaid interest thereon (including interest accrued thereon at the applicable Default Rate) and (y) the Make-Whole Amount determined in respect of such principal amount, shall all be immediately due and payable, in each and every case without presentment, demand, protest or further notice, all of which are hereby waived. The Company acknowledges, and the parties hereto agree, that each holder of a Note has the right to maintain its investment in the Notes free from repayment by the Company (except as herein specifically provided for) and that the provision for payment of a Make-Whole Amount by the Company in the event that the Notes are prepaid or are accelerated as a result of an Event of Default, is intended to provide compensation for the deprivation of such right under such circumstances.

    Section 12.2.    Other Remedies. If any Default or Event of Default has occurred and is continuing, and irrespective of whether any Notes have become or have been declared immediately due and payable under Section 12.1, the holder of any Note at the time outstanding may proceed to protect and enforce the rights of such holder by an action at law, suit in equity or other appropriate proceeding, whether for the specific performance of any agreement contained

-34-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

herein or in any Note or Guaranty Agreement, or for an injunction against a violation of any of the terms hereof or thereof, or in aid of the exercise of any power granted hereby or thereby or by law or otherwise.

    Section 12.3.    Rescission. At any time after any Notes have been declared due and payable pursuant to Section 12.1(b) or (c), the Required Holders, by written notice to the Company, may rescind and annul any such declaration and its consequences if (a) the Company has paid all overdue interest on the Notes, all principal of and Make-Whole Amount, if any, on any Notes that are due and payable and are unpaid other than by reason of such declaration, and all interest on such overdue principal and Make-Whole Amount, if any, and (to the extent permitted by applicable law) any overdue interest in respect of the Notes, at the applicable Default Rate, (b) neither the Company nor any other Person shall have paid any amounts which have become due solely by reason of such declaration, (c) all Events of Default and Defaults, other than non-payment of amounts that have become due solely by reason of such declaration, have been cured or have been waived pursuant to Section 17, and (d) no judgment or decree has been entered for the payment of any monies due pursuant hereto or to the Notes. No rescission and annulment under this Section 12.3 will extend to or affect any subsequent Event of Default or Default or impair any right consequent thereon.

    Section 12.4.    No Waivers or Election of Remedies, Expenses, Etc. No course of dealing and no delay on the part of any holder of any Note in exercising any right, power or remedy shall operate as a waiver thereof or otherwise prejudice such holder’s rights, powers or remedies. No right, power or remedy conferred by this Agreement, any Guaranty Agreement or any Note upon any holder thereof shall be exclusive of any other right, power or remedy referred to herein or therein or now or hereafter available at law, in equity, by statute or otherwise. Without limiting the obligations of the Company under Section 15, the Company will pay to the holder of each Note on demand such further amount as shall be sufficient to cover all costs and expenses of such holder incurred in any enforcement or collection under this Section 12, including reasonable attorneys’ fees, expenses and disbursements.

Section 13.    Registration; Exchange; Substitution of Notes.

    Section 13.1.    Registration of Notes. The Company, or a registrar agent designated by the Company, shall keep at its principal executive office a register for the registration and registration of transfers of Notes. The name and address of each holder of one or more Notes, each transfer thereof and the name and address of each transferee of one or more Notes shall be registered in such register. If any holder of one or more Notes is a nominee, then (a) the name and address of the beneficial owner of such Note or Notes shall also be registered in such register as an owner and holder thereof and (b) at any such beneficial owner’s option, either such beneficial owner or its nominee may execute any amendment, waiver or consent pursuant to this Agreement. Prior to due presentment for registration of transfer, the Person in whose name any Note shall be registered shall be deemed and treated as the owner and holder thereof for all purposes hereof, and the Company shall not be affected by any notice or knowledge to the contrary. The Company shall give to any holder of a Note that is an Institutional Investor promptly upon request therefor, a complete and correct copy of the names and addresses of all registered holders of Notes.

-35-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

    Section 13.2.    Transfer and Exchange of Notes. Upon surrender of any Note to the Company at the address and to the attention of the designated officer (all as specified in Section 18(iii)), for registration of transfer or exchange (and in the case of a surrender for registration of transfer accompanied by a written instrument of transfer duly executed by the registered holder of such Note or such holder’s attorney duly authorized in writing and accompanied by the relevant name, address and other information for notices of each transferee of such Note or part thereof), within 10 Business Days thereafter, the Company shall execute and deliver, at the Company’s expense (except as provided below), one or more new Notes of the same series (as requested by the holder thereof) in exchange therefor, in an aggregate principal amount equal to the unpaid principal amount of the surrendered Note. Each such new Note shall be payable to such Person as such holder may request and shall be substantially in the form of Schedule 1(a) or Schedule 1(b), as applicable. Each such new Note shall be dated and bear interest from the date to which interest shall have been paid on the surrendered Note or dated the date of the surrendered Note if no interest shall have been paid thereon. The Company may require payment of a sum sufficient to cover any stamp tax or governmental charge imposed in respect of any such transfer of Notes. Notes shall not be transferred in denominations of less than $100,000, provided that if necessary to enable the registration of transfer by a holder of its entire holding of Notes of a series, one Note of such series may be in a denomination of less than $100,000. Any transferee, by its acceptance of a Note registered in its name (or the name of its nominee), shall be deemed to have made the representation set forth in Section 6.2.

    Section 13.3.    Replacement of Notes. Upon receipt by the Company at the address and to the attention of the designated officer (all as specified in Section 18(iii)) of evidence reasonably satisfactory to it of the ownership of and the loss, theft, destruction or mutilation of any Note (which evidence shall be, in the case of an Institutional Investor, notice from such Institutional Investor of such ownership and such loss, theft, destruction or mutilation), and

    (a)    in the case of loss, theft or destruction, of indemnity reasonably satisfactory to it (provided that if the holder of such Note is, or is a nominee for, an original Purchaser or another holder of a Note with a minimum net worth of at least $25,000,000 or a Qualified Institutional Buyer, such Person’s own unsecured agreement of indemnity shall be deemed to be satisfactory), or

    (b)    in the case of mutilation, upon surrender and cancellation thereof,

within 10 Business Days thereafter, the Company at its own expense shall execute and deliver, in lieu thereof, a new Note, dated and bearing interest from the date to which interest shall have been paid on such lost, stolen, destroyed or mutilated Note or dated the date of such lost, stolen, destroyed or mutilated Note if no interest shall have been paid thereon.

Section 14.    Payments on Notes.

    Section 14.1.    Place of Payment. Subject to Section 14.2, payments of principal, Make-Whole Amount, if any, and interest becoming due and payable on the Notes shall be made in New York, New York. The Company may at any time, by notice to each holder of a Note, change the place of payment of the Notes so long as such place of payment shall be either the

-36-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

principal office of the Company in such jurisdiction or the principal office of a bank or trust company in such jurisdiction.

    Section 14.2.    Payment by Wire Transfer. So long as any Purchaser or its nominee shall be the holder of any Note, and notwithstanding anything contained in Section 14.1 or in such Note to the contrary, the Company will pay or will cause to be paid all sums becoming due on such Note for principal, Make-Whole Amount, if any, interest and all other amounts becoming due hereunder by the method and at the address specified for such purpose below such Purchaser’s name in the Purchaser Schedule, or by such other method or at such other address as such Purchaser shall have from time to time specified to the Company in writing for such purpose, without the presentation or surrender of such Note or the making of any notation thereon, except that upon written request of the Company made concurrently with or reasonably promptly after payment or prepayment in full of any Note, such Purchaser shall surrender such Note for cancellation, reasonably promptly after any such request, to the Company at its principal executive office or at the place of payment most recently designated by the Company pursuant to Section 14.1. Prior to any sale or other disposition of any Note held by a Purchaser or its nominee, such Purchaser will, at its election, either endorse thereon the amount of principal paid thereon and the last date to which interest has been paid thereon or surrender such Note to the Company in exchange for a new Note or Notes pursuant to Section 13.2. The Company will afford the benefits of this Section 14.2 to any Institutional Investor that is the direct or indirect transferee of any Note purchased by a Purchaser under this Agreement and that has made the same agreement relating to such Note as the Purchasers have made in this Section 14.2.

    Section 14.3.        FATCA Information. By acceptance of any Note, the holder of such Note agrees that such holder will with reasonable promptness duly complete and deliver to the Company, or to such other Person as may be reasonably requested by the Company, from time to time (a) in the case of any such holder that is a United States Person, such holder’s United States tax identification number or other Forms reasonably requested by the Company necessary to establish such holder’s status as a United States Person under FATCA and as may otherwise be necessary for the Company to comply with its obligations under FATCA and (b) in the case of any such holder that is not a United States Person, such documentation prescribed by applicable law (including as prescribed by section 1471(b)(3)(C)(i) of the Code) and such additional documentation as may be necessary for the Company to comply with its obligations under FATCA and to determine that such holder has complied with such holder’s obligations under FATCA or to determine the amount (if any) to deduct and withhold from any such payment made to such holder. Nothing in this Section 14.3 shall require any holder to provide information that is confidential or proprietary to such holder unless the Company is required to obtain such information under FATCA and, in such event, the Company shall treat any such information it receives as confidential.

Except as otherwise required by applicable law, the Company agrees that it will not withhold from any applicable payment to be made to a holder of a Note that is not a United States Person any tax so long as such holder shall have delivered to the Company (in such number of copies as shall be requested), on or about the date on which such holder becomes a holder under this Agreement (and from time to time thereafter upon the reasonable request of the Company), executed copies of IRS Form W-8BEN or IRS Form W-8BEN-E, as applicable, as well as the

-37-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

applicable “U.S. Tax Compliance Certificate” substantially in the form attached as Exhibit 14.3, in both cases correctly completed and executed and validly claiming a complete exemption from U.S. federal withholding tax.

Section 15.    Expenses, Etc.

    Section 15.1.    Transaction Expenses. Whether or not the transactions contemplated hereby are consummated, the Company will pay all costs and expenses (including reasonable attorneys’ fees of a special counsel and, if reasonably required by the Required Holders, local or other counsel) incurred by the Purchasers and each other holder of a Note in connection with such transactions and in connection with any amendments, waivers or consents under or in respect of this Agreement, any Guaranty Agreement or the Notes (whether or not such amendment, waiver or consent becomes effective), including: (a) the costs and expenses incurred in enforcing or defending (or determining whether or how to enforce or defend) any rights under this Agreement, any Guaranty Agreement or the Notes or in responding to any subpoena or other legal process or informal investigative demand issued in connection with this Agreement, any Guaranty Agreement or the Notes, or by reason of being a holder of any Note, (b) the costs and expenses, including financial advisors’ fees, incurred in connection with the insolvency or bankruptcy of the Company or any Subsidiary or in connection with any work-out or restructuring of the transactions contemplated hereby and by the Notes and any Guaranty Agreement and (c) the costs and expenses incurred in connection with the initial filing of this Agreement and all related documents and financial information with the SVO provided, that such costs and expenses under this clause (c) shall not exceed $5,000 for each series of Notes. If required by the NAIC, the Company shall obtain and maintain at its own cost and expense a Legal Entity Identifier (LEI).

        The Company will pay, and will save each Purchaser and each other holder of a Note harmless from, (i) all claims in respect of any fees, costs or expenses, if any, of brokers and finders (other than those, if any, retained by a Purchaser or other holder in connection with its purchase of the Notes), (ii) any and all wire transfer fees that any bank or other financial institution deducts from any payment under such Note to such holder or otherwise charges to a holder of a Note with respect to a payment under such Note and (iii) any judgment, liability, claim, order, decree, fine, penalty, cost, fee, expense (including reasonable attorneys’ fees and expenses) or obligation resulting from the consummation of the transactions contemplated hereby, including the use of the proceeds of the Notes by the Company.

    Section 15.2.    Certain Taxes. The Company agrees to pay all stamp, documentary or similar taxes or fees which may be payable in respect of the execution and delivery or the enforcement of this Agreement or any Guaranty Agreement or the execution and delivery (but not the transfer) or the enforcement of any of the Notes in the United States or any other jurisdiction where the Company or any Guarantor has assets or of any amendment of, or waiver or consent under or with respect to, this Agreement or any Guaranty Agreement or of any of the Notes, and to pay any value added tax due and payable in respect of reimbursement of costs and expenses by the Company pursuant to this Section 15, and will save each holder of a Note to the extent permitted by applicable law harmless against any loss or liability resulting from

-38-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

nonpayment or delay in payment of any such tax or fee required to be paid by the Company hereunder.

    Section 15.3.    Survival. The obligations of the Company under this Section 15 will survive the payment or transfer of any Note, the enforcement, amendment or waiver of any provision of this Agreement, any Guaranty Agreement or the Notes, and the termination of this Agreement.

Section 16.    Survival of Representations and Warranties; Entire Agreement.

All representations and warranties contained herein shall survive the execution and delivery of this Agreement and the Notes, the purchase or transfer by any Purchaser of any Note or portion thereof or interest therein and the payment of any Note, and may be relied upon by any subsequent holder of a Note, regardless of any investigation made at any time by or on behalf of such Purchaser or any other holder of a Note. All statements contained in any certificate or other instrument delivered by or on behalf of the Company pursuant to this Agreement shall be deemed representations and warranties of the Company under this Agreement. Subject to the preceding sentence, this Agreement, the Notes and any Guaranty Agreements embody the entire agreement and understanding between each Purchaser and the Company and supersede all prior agreements and understandings relating to the subject matter hereof.

Section 17.    Amendment and Waiver.

    Section 17.1.    Requirements. This Agreement and the Notes may be amended, and the observance of any term hereof or of the Notes may be waived (either retroactively or prospectively), only with the written consent of the Company and the Required Holders, except that:

    (a)    no amendment or waiver of any of Sections 1, 2, 3, 4, 5, 6 or 21 hereof, or any defined term (as it is used therein), will be effective as to any Purchaser unless consented to by such Purchaser in writing; and

    (b)     no amendment or waiver may, without the written consent of each Purchaser and the holder of each Note at the time outstanding, (i) subject to Section 12 relating to acceleration or rescission, change the amount or time of any prepayment or payment of principal of, or reduce the rate or change the time of payment or method of computation of (x) interest on the Notes or (y) the Make-Whole Amount, (ii) change the percentage of the principal amount of the Notes the holders of which are required to consent to any amendment or waiver, or (iii) change the principal amount of the Notes that the Purchasers are to purchase pursuant to Section 2 upon the satisfaction of the conditions to Closing that appear in Section 4, or (iv) amend any of Sections 8 (except as set forth in the second sentence of Section 8.2), 11(a), 11(b), 12, 17, or 20.

-39-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

    Section 17.2.    Solicitation of Holders of Notes.

    (a)    Solicitation. The Company will provide each Purchaser and each holder of a Note with sufficient information, sufficiently far in advance of the date a decision is required, to enable such Purchaser and such holder to make an informed and considered decision with respect to any proposed amendment, waiver or consent in respect of any of the provisions hereof or of the Notes or any Guaranty Agreement. The Company will deliver executed or true and correct copies of each amendment, waiver or consent effected pursuant to this Section 17 or any Guaranty Agreement to each Purchaser and each holder of a Note promptly following the date on which it is executed and delivered by, or receives the consent or approval of, the requisite Purchasers or holders of Notes.

    (b)    Payment. The Company will not directly or indirectly pay or cause to be paid any remuneration, whether by way of supplemental or additional interest, fee or otherwise, or grant any security or provide other credit support, to any Purchaser or holder of a Note as consideration for or as an inducement to the entering into by such Purchaser or holder of any waiver or amendment of any of the terms and provisions hereof or of any Guaranty or any Note unless such remuneration is concurrently paid, or security is concurrently granted or other credit support concurrently provided, on the same terms, ratably to each Purchaser and holder of a Note even if such Purchaser or holder did not consent to such waiver or amendment.

    (c)    Consent in Contemplation of Transfer. Any consent given pursuant to this Section 17 or any Guaranty Agreement by a holder of a Note that has transferred or has agreed to transfer its Note to (i) the Company, (ii) any Subsidiary or any other Affiliate or (iii) any other Person in connection with, or in anticipation of, such other Person acquiring, making a tender offer for or merging with the Company and/or any of its Affiliates, in each case in connection with such consent, shall be void and of no force or effect except solely as to such holder, and any amendments effected or waivers granted or to be effected or granted that would not have been or would not be so effected or granted but for such consent (and the consents of all other holders of Notes that were acquired under the same or similar conditions) shall be void and of no force or effect except solely as to such holder.

    Section 17.3.    Binding Effect, Etc. Any amendment or waiver consented to as provided in this Section 17 or any Guaranty applies equally to all Purchasers and holders of Notes and is binding upon them and upon each future holder of any Note and upon the Company without regard to whether such Note has been marked to indicate such amendment or waiver. No such amendment or waiver will extend to or affect any obligation, covenant, agreement, Default or Event of Default not expressly amended or waived or impair any right consequent thereon. No course of dealing between the Company and any Purchaser or holder of a Note and no delay in exercising any rights hereunder or under any Note or Guaranty shall operate as a waiver of any rights of any Purchaser or holder of such Note.

    Section 17.4.    Notes Held by Company, Etc. Solely for the purpose of determining whether the holders of the requisite percentage of the aggregate principal amount of Notes then outstanding approved or consented to any amendment, waiver or consent to be given under this Agreement, any Guaranty Agreement or the Notes, or have directed the taking of any action

-40-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

provided herein or in any Guaranty Agreement or the Notes to be taken upon the direction of the holders of a specified percentage of the aggregate principal amount of Notes then outstanding, Notes directly or indirectly owned by the Company or any of its Affiliates shall be deemed not to be outstanding.

Section 18.    Notices.

Except to the extent otherwise provided in Section 7.4, all notices and communications provided for hereunder shall be in writing and sent (a) by telecopy if the sender on the same day sends a confirming copy of such notice by an internationally recognized overnight delivery service (charges prepaid), or (b) by registered or certified mail with return receipt requested (postage prepaid), or (c) by an internationally recognized overnight delivery service (charges prepaid). Any such notice must be sent:

    (i)    if to any Purchaser or its nominee, to such Purchaser or nominee at the address specified for such communications in the Purchaser Schedule, or at such other address as such Purchaser or nominee shall have specified to the Company in writing,

    (ii)    if to any other holder of any Note, to such holder at such address as such other holder shall have specified to the Company in writing, or

    (iii)    if to the Company, to the Company at its address set forth at the beginning hereof to the attention of the treasurer of the Company, or at such other address as the Company shall have specified to the holder of each Note in writing.

Notices under this Section 18 will be deemed given only when actually received.

Section 19.    Reproduction of Documents.

This Agreement and all documents relating thereto, including (a) consents, waivers and modifications that may hereafter be executed, (b) documents received by any Purchaser at the applicable Closing (except the Notes themselves), and (c) financial statements, certificates and other information previously or hereafter furnished to any Purchaser, may be reproduced by such Purchaser by any photographic, photostatic, electronic, digital, or other similar process and such Purchaser may destroy any original document so reproduced. The Company agrees and stipulates that, to the extent permitted by applicable law, any such reproduction shall be admissible in evidence as the original itself in any judicial or administrative proceeding (whether or not the original is in existence and whether or not such reproduction was made by such Purchaser in the regular course of business) and any enlargement, facsimile or further reproduction of such reproduction shall likewise be admissible in evidence. This Section 19 shall not prohibit the Company or any other holder of Notes from contesting any such reproduction to the same extent that it could contest the original, or from introducing evidence to demonstrate the inaccuracy of any such reproduction.

-41-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

Section 20.    Confidential Information.

For the purposes of this Section 20, “Confidential Information” means information delivered to any Purchaser by or on behalf of the Company or any Subsidiary in connection with the transactions contemplated by or otherwise pursuant to this Agreement that is proprietary in nature and that was clearly marked or labeled or otherwise adequately identified when received by such Purchaser as being confidential information of the Company or such Subsidiary, provided that such term does not include information that (a) was publicly known or otherwise known to such Purchaser prior to the time of such disclosure, (b) subsequently becomes publicly known through no act or omission by such Purchaser or any Person acting on such Purchaser’s behalf, (c) otherwise becomes known to such Purchaser other than through disclosure by the Company or any Subsidiary or (d) constitutes financial statements delivered to such Purchaser under Section 7.1 that are otherwise publicly available. Each Purchaser will maintain the confidentiality of such Confidential Information in accordance with procedures adopted by such Purchaser in good faith to protect confidential information of third parties delivered to such Purchaser, provided that such Purchaser may deliver or disclose Confidential Information to (i) its affiliates and its and its affiliates’ respective directors, officers, employees (legal or contractual), agents, partners, attorneys, trustees, limited partners and investors (in each case to the extent such disclosure reasonably relates to the administration of the investment represented by its Notes or portfolio management), (ii) its auditors, consultants, service providers, financial advisors, investment managers, investment advisors and other professional advisors who agree to hold confidential the Confidential Information substantially in accordance with this Section 20, (iii) any other holder of any Note, (iv) if the holder of a Note is a trust or fund, to the beneficiaries or beneficial owners of such trust or fund, (v) any Institutional Investor to which it transfers or pledges or offers to transfer or pledge such Note or any part thereof or any participation therein and any beneficiary, agent, custodian or trustee in connection therewith (if such Person has agreed prior to its receipt of such Confidential Information to hold the information confidential substantially in accordance with this Section 20) and, in each case, any such Person shall have the same rights and obligations with respect to such Confidential Information as the Purchasers have under this Section 20, (vi) any Person from which it offers to purchase any security of the Company (if such Person has agreed in writing prior to its receipt of such Confidential Information to be bound by this Section 20), (vii) any federal, state or other regulatory authority having jurisdiction over such Purchaser, any recipient of Confidential Information under this Section 20, or in each case, its portfolio or any transactions relating thereto, (viii) the NAIC or the SVO or, in each case, any similar organization, or any nationally recognized rating agency, or (ix) any other Person to which such delivery or disclosure may be necessary or appropriate (w) to effect compliance with any law, rule, regulation or order applicable to such Purchaser or its investment managers or investment advisors or to its investment portfolio or any transactions relating thereto (x) in response to any subpoena or other legal process, (y) in connection with any litigation, arbitration or dispute resolution process to which such Purchaser is a party or (z) if an Event of Default has occurred and is continuing, to the extent such Purchaser may reasonably determine such delivery and disclosure to be necessary or appropriate in the enforcement or for the protection of the rights and remedies under such Purchaser’s Notes, this Agreement or any Subsidiary Guaranty. Each holder of a Note, by its acceptance of a Note, will be deemed to have agreed to be bound by and to be entitled to the benefits of this Section 20 as though it were a party to this Agreement. On reasonable request by

-42-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

the Company in connection with the delivery to any holder of a Note of information required to be delivered to such holder under this Agreement or requested by such holder (other than a holder that is a party to this Agreement or its nominee), such holder will enter into an agreement with the Company embodying this Section 20.

In the event that as a condition to receiving access to information relating to the Company or its Subsidiaries in connection with the transactions contemplated by or otherwise pursuant to this Agreement, any Purchaser or holder of a Note is required to agree to a confidentiality undertaking (whether through Intralinks, another secure website, a secure virtual workspace or otherwise) which is different from this Section 20, this Section 20 shall not be amended thereby and, as between such Purchaser or such holder and the Company, this Section 20 shall supersede any such other confidentiality undertaking.

Section 21.    Substitution of Purchaser.

Each Purchaser shall have the right to substitute any one of its Affiliates or another Purchaser or any one of such other Purchaser’s Affiliates (a “Substitute Purchaser”) as the purchaser of the Notes that it has agreed to purchase hereunder, by written notice to the Company, which notice shall be signed by both such Purchaser and such Substitute Purchaser, shall contain such Substitute Purchaser’s agreement to be bound by this Agreement and shall contain a confirmation by such Substitute Purchaser of the accuracy with respect to it of the representations set forth in Section 6. Upon receipt of such notice, any reference to such Purchaser in this Agreement (other than in this Section 21), shall be deemed to refer to such Substitute Purchaser in lieu of such original Purchaser. In the event that such Substitute Purchaser is so substituted as a Purchaser hereunder and such Substitute Purchaser thereafter transfers to such original Purchaser all of the Notes then held by such Substitute Purchaser, upon receipt by the Company of notice of such transfer, any reference to such Substitute Purchaser as a “Purchaser” in this Agreement (other than in this Section 21), shall no longer be deemed to refer to such Substitute Purchaser, but shall refer to such original Purchaser, and such original Purchaser shall again have all the rights of an original holder of the Notes under this Agreement.

Section 22.    Miscellaneous.

    Section 22.1.    Successors and Assigns. All covenants and other agreements contained in this Agreement by or on behalf of any of the parties hereto bind and inure to the benefit of their respective successors and assigns (including any subsequent holder of a Note) whether so expressed or not, except that, subject to Section 10.2, the Company may not assign or otherwise transfer any of its rights or obligations hereunder or under the Notes without the prior written consent of each holder. Nothing in this Agreement, expressed or implied, shall be construed to confer upon any Person (other than the parties hereto and their respective successors and assigns permitted hereby) any legal or equitable right, remedy or claim under or by reason of this Agreement.

    Section 22.2.    Accounting Terms. All accounting terms used herein which are not expressly defined in this Agreement have the meanings respectively given to them in accordance with GAAP. Except as otherwise specifically provided herein, (i) all computations made

-43-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

pursuant to this Agreement shall be made in accordance with GAAP, and (ii) all financial statements shall be prepared in accordance with GAAP. For purposes of determining compliance with this Agreement (including Section 9, Section 10 and the definition of “Indebtedness”), any election by the Company to measure any financial liability using fair value (as permitted by Financial Accounting Standards Board Accounting Standards Codification Topic No. 825-10-25 – Fair Value Option, International Financial Reporting Standards 39 – Financial Instruments or any similar accounting standard) shall be disregarded and such determination shall be made as if such election had not been made.

    Section 22.3.    Severability. Any provision of this Agreement that is prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective to the extent of such prohibition or unenforceability without invalidating the remaining provisions hereof, and any such prohibition or unenforceability in any jurisdiction shall (to the full extent permitted by law) not invalidate or render unenforceable such provision in any other jurisdiction.

    Section 22.4.    Construction, Etc. Each covenant contained herein shall be construed (absent express provision to the contrary) as being independent of each other covenant contained herein, so that compliance with any one covenant shall not (absent such an express contrary provision) be deemed to excuse compliance with any other covenant. Where any provision herein refers to action to be taken by any Person, or which such Person is prohibited from taking, such provision shall be applicable whether such action is taken directly or indirectly by such Person.

Defined terms herein shall apply equally to the singular and plural forms of the terms defined. Whenever the context may require, any pronoun shall include the corresponding masculine, feminine and neuter forms. The words “include,” “includes” and “including” shall be deemed to be followed by the phrase “without limitation.” The word “will” shall be construed to have the same meaning and effect as the word “shall.” Unless the context requires otherwise (a) any definition of or reference to any agreement, instrument or other document herein shall be construed as referring to such agreement, instrument or other document as from time to time amended, supplemented or otherwise modified (subject to any restrictions on such amendments, supplements or modifications set forth herein) and, for purposes of the Notes, shall also include any such notes issued in substitution therefor pursuant to Section 13, (b) subject to Section 22.1, any reference herein to any Person shall be construed to include such Person’s successors and assigns, (c) the words “herein,” “hereof” and “hereunder,” and words of similar import, shall be construed to refer to this Agreement in its entirety and not to any particular provision hereof, (d) all references herein to Sections and Schedules shall be construed to refer to Sections of, and Schedules to, this Agreement, and (e) any reference to any law or regulation herein shall, unless otherwise specified, refer to such law or regulation as amended, modified or supplemented from time to time.

    Section 22.5.    Counterparts; Signatures. This Agreement may be executed in any number of counterparts, each of which shall be an original but all of which together shall constitute one instrument. Each counterpart may consist of a number of copies hereof, each signed by less than all, but together signed by all, of the parties hereto. The words “execution”, “signed” and “signature” and words of like import in this Agreement or documents relating to

-44-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

this Agreement shall include manually executed signatures transmitted by facsimile or other electronic formats (including, without limitation, “pdf”, “tif” or “jpg”) and other electronic signatures (including, without limitation, AdobeSign).

    Section 22.6.    Governing Law. This Agreement shall be construed and enforced in accordance with, and the rights of the parties shall be governed by, the law of the State of New York excluding choice-of-law principles of the law of such State that would permit the application of the laws of a jurisdiction other than such State.

    Section 22.7.    Jurisdiction and Process; Waiver of Jury Trial. (a) The Company irrevocably submits to the non-exclusive jurisdiction of any New York State or federal court sitting in the Borough of Manhattan, The City of New York, over any suit, action or proceeding arising out of or relating to this Agreement or the Notes. To the fullest extent permitted by applicable law, the Company irrevocably waives and agrees not to assert, by way of motion, as a defense or otherwise, any claim that it is not subject to the jurisdiction of any such court, any objection that it may now or hereafter have to the laying of the venue of any such suit, action or proceeding brought in any such court and any claim that any such suit, action or proceeding brought in any such court has been brought in an inconvenient forum.

    (b)    The Company agrees, to the fullest extent permitted by applicable law, that a final judgment in any suit, action or proceeding of the nature referred to in Section 22.7(a) brought in any such court shall be conclusive and binding upon it subject to rights of appeal, as the case may be, and may be enforced in the courts of the United States of America or the State of New York (or any other courts to the jurisdiction of which it or any of its assets is or may be subject) by a suit upon such judgment.

    (c)    The Company consents to process being served by or on behalf of any holder of Notes in any suit, action or proceeding of the nature referred to in Section 22.7(a) by mailing a copy thereof by registered, certified, priority or express mail (or any substantially similar form of mail), postage prepaid, return receipt or delivery confirmation requested, to it at its address specified in Section 18 or at such other address of which such holder shall then have been notified pursuant to said Section. The Company agrees that such service upon receipt (i) shall be deemed in every respect effective service of process upon it in any such suit, action or proceeding and (ii) shall, to the fullest extent permitted by applicable law, be taken and held to be valid personal service upon and personal delivery to it. Notices hereunder shall be conclusively presumed received as evidenced by a delivery receipt furnished by the United States Postal Service or any reputable commercial delivery service.

    (d)    Nothing in this Section 22.7 shall affect the right of any holder of a Note to serve process in any manner permitted by law, or limit any right that the holders of any of the Notes may have to bring proceedings against the Company in the courts of any appropriate jurisdiction or to enforce in any lawful manner a judgment obtained in one jurisdiction in any other jurisdiction.

-45-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

    (e)    The parties hereto hereby waive trial by jury in any action brought on or with respect to this Agreement, the Notes or any other document executed in connection herewith or therewith.

-46-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

If you are in agreement with the foregoing, please sign the form of agreement on a counterpart of this Agreement and return it to the Company, whereupon this Agreement shall become a binding agreement between you and the Company.

    Very truly yours,

    Ameren Transmission Company of Illinois

    By  /s/ Mitchell J. Lansford                        

    Name: Mitchell J. Lansford

    Title: Vice President and Treasurer

-47-

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

American General Life Insurance Company

By:    Corebridge Institutional Investments (U.S.), LLC, as Investment Adviser

    By /s/ David Etlinger                                  

Name: David Etlinger

Title: Senior Vice President

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

Teachers Insurance and Annuity Association of America, a New York domiciled life insurance company

By:    Nuveen Alternatives Advisors LLC,
a Delaware limited liability company,
its investment manager

    By  /s/ Joseph R. Cantey                              

Name: Joseph R. Cantey

Title: Managing Director

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

State Farm Life Insurance Company

By:  /s/ Rebekah L. Holt                                            

Name:    Rebekah L. Holt

Title:     Investment Professional

By:  /s/ Michelle K. Marsh                                         

Name:    Michelle K. Marsh

Title:     Investment Professional

State Farm Life and Accident Assurance Company

By:  /s/ Rebekah L. Holt                                            

Name:    Rebekah L. Holt

Title:     Investment Professional

By:  /s/ Michelle K. Marsh                                         

Name:    Michelle K. Marsh

Title:     Investment Professional

State Farm Insurance Companies Employee Retirement Trust

By:  /s/ Rebekah L. Holt                                            

Name:    Rebekah L. Holt

Title:     Authorized Signer

By:  /s/ Michelle K. Marsh                                         

Name: Michelle K. Marsh

Title:     Authorized Signer

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

    Metropolitan Tower Life Insurance Company

    By:    MetLife Investment Management, LLC, Its Investment Manager

By  /s/ Kathryn Bai                                              

    Name: Kathryn Bai

    Title: Authorized Signatory

    Metlife Reinsurance Company of Hamilton, Ltd.

    By:    MetLife Investment Management, LLC, Its Investment Manager

By  /s/ Kathryn Bai                                              

    Name: Kathryn Bai

    Title: Authorized Signatory

    MetLife Insurance Company of Korea Limited

    By:    MetLife Investment Management, LLC, Its Investment Manager

By  /s/ Kathryn Bai                                              

    Name: Kathryn Bai

    Title: Authorized Signatory

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

The Guardian Life Insurance Company of America

By:    HPS Investment Partners, LLC, its Sub-Manager

By:  /s/ Trinh Nguyen                                                

Name: Trinh Nguyen

Title: Managing Director

Berkshire Life Insurance Company of America

By:    HPS Investment Partners, LLC, its Sub-Manager

By:  /s/ Trinh Nguyen                                                

Name: Trinh Nguyen

Title: Managing Director

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

Thrivent Financial for Lutherans

By:  /s/ Robinson Ewald                                            

Name: Robinson Ewald

Title: Senior Research Analyst

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

    The Northwestern Mutual Life Insurance Company

    By:    Northwestern Mutual Investment Management Company, LLC, its investment advisor

By:  /s/ Jeffrey Behring                                              

Name: Jeffrey Behring

Title: Managing Director

    The Northwestern Mutual Life Insurance Company for its Group Annuity Separate Account

    By:    Northwestern Mutual Investment Management Company, LLC, its investment advisor

By:  /s/ Jeffrey Behring                                              

Name: Jeffrey Behring

Its: Managing Director

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

RGA Reinsurance Company

By:  /s/ Curtis Spillers                                                

Name: Curtis Spillers

Title: Vice President

RGA Americas Reinsurance Company, LTD

By:  /s/ Curtis Spillers                                                

Name: Curtis Spillers

Title: Vice President

RGA Reinsurance Company Barbados LTD

By:  /s/ Curtis Spillers                                                

Name: Curtis Spillers

Title: Vice President

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

    Modern Woodmen of America

By:  /s/ Robert D. Cleppe                                           

Name: Robert D. Cleppe

Title: Chief Investment Officer & Treasurer

By:  /s/ Aaron R. Birkland                                         

Name: Aaron R. Birkland

Title: Sr. Portfolio Manager, Private Placements

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

    American United Life Insurance Company

By:  /s/ Craig Lehman                                              

Name: Craig Lehman

Title: VP, Fixed Income Securities

The State Life Insurance Company,

By: American United Life Insurance Company

Its: Authorized Agent

By:  /s/ Craig Lehman                                              

Name: Craig Lehman

Title: VP, Fixed Income Securities

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

    Unum Life Insurance Company of America

By:    Provident Investment Management, LLC

Its:    Agent

    By:  /s/ Ben Vance                                            

Name: Ben Vance

Title: Vice President, Senior Managing Director

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

John Hancock Life Insurance Company (U.S.A.)

By:  /s/ Mariana Primera                                            

Name: Mariana Primera

Title: AVP

John Hancock Life & Health Insurance Company

By:  /s/ Mariana Primera                                            

Name: Mariana Primera

Title: AVP

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

    CMFG Life Insurance Company

By:    MEMBERS Capital Advisors, Inc., (d/b/a TruStage Investment Management)
acting as Investment Advisor

By:  /s/ Stan J. Van Aartsen                                       

Name: Stan J. Van Aartsen

Title: Managing Director, Investments

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

    Ameritas Life Insurance Corp.,
a Nebraska corporation

By:  /s/ Michael R. Gatliff                                          

Name: Michael R. Gatliff

Title: Authorized Representative

    Ameritas Life Insurance Corp. of New York,
a New York corporation

By:  /s/ Michael R. Gatliff                                          

Name: Michael R. Gatliff

Title: Authorized Representative

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

    Liberty National Life Insurance Company

By:  /s/ Chris Colamarino                                          

Name: Chris Colamarino

Title:    Divisional Senior Vice President, Investments

    Liberty National Life Insurance Company

By:  /s/ Travis Korth                                                  

Name: Travis Korth

Title:    Divisional Senior Vice President, Investments

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

    Life Insurance Company of the Southwest

By:  /s/ Chris Hume                                                   

Name: Chris Hume

Title: Executive Director, Private Placements, NLG Capital LLC as investment adviser

---

Ameren Transmission Company of Illinois        Note Purchase Agreement

This Agreement is hereby

accepted and agreed to as

of the date hereof.

    Southern Farm Bureau Life Insurance Company

By:  /s/ Bradley Blakney                                            

Name: Bradley Blakney

Title: Director

---

Defined Terms

As used herein, the following terms have the respective meanings set forth below or set forth in the Section hereof following such term:

“Acceptable Rating Agency” means (a) each of Moody’s Investors Service, Inc., S&P Global Ratings, a division of S&P Global Inc., Fitch Ratings, Inc., DBRS, Kroll Bond Rating Agency, or any successor thereto, or (b) any other credit rating agency that is recognized as a nationally recognized statistical rating organization by the SEC (other than Egan-Jones Ratings Company) and approved by the Required Holders, so long as, in each case, (i) any such credit rating agency described in clause (a) or (b) above continues to be a nationally recognized statistical rating organization recognized by the SEC and is approved as a “Credit Rating Provider” (or other similar designation) by the NAIC and (ii) such Acceptable Rating Agency is retained by the Company.

“Affiliate” means, at any time, and with respect to any Person, any other Person that at such time directly or indirectly through one or more intermediaries Controls, or is Controlled by, or is under common Control with, such first Person. Unless the context otherwise clearly requires, any reference to an “Affiliate” is a reference to an Affiliate of the Company.

“Agreement” means this Note Purchase Agreement, including all Schedules attached to this Agreement.

“Ameren” means Ameren Corporation, a Missouri corporation, the direct or indirect owner of 100% of the capital stock of the Company.

“Anti-Corruption Laws” means any law or regulation in a U.S. or any non-U.S. jurisdiction regarding bribery or any other corrupt activity, including the U.S. Foreign Corrupt Practices Act and the U.K. Bribery Act 2010.

“Anti-Money Laundering Laws” means any law or regulation in a U.S. or any non-U.S. jurisdiction regarding money laundering, drug trafficking, terrorist-related activities or other money laundering predicate crimes, including the Currency and Foreign Transactions Reporting Act of 1970 (otherwise known as the Bank Secrecy Act) and the USA PATRIOT Act.

“Blocked Person” means (a) a Person whose name appears on the list of Specially Designated Nationals and Blocked Persons published by OFAC, (b) a Person, entity, organization, country or regime that is blocked or a target of sanctions that have been imposed under U.S. Economic Sanctions Laws or (c) a Person that is an agent, department or instrumentality of, or is otherwise beneficially owned by, controlled by or acting on behalf of, directly or indirectly, any Person, entity, organization, country or regime described in clause (a) or (b).

“Business Day” means (a) for the purposes of Section 8.6 only, any day other than a Saturday, a Sunday or a day on which commercial banks in New York City are required or authorized to be closed, and (b) for the purposes of any other provision of this Agreement, any

Schedule A
(to Note Purchase Agreement)

---

day other than a Saturday, a Sunday or a day on which commercial banks in New York, New York or Chicago, Illinois are required or authorized to be closed.

“Capital Lease” means, at any time, a lease with respect to which the lessee is required concurrently to recognize the acquisition of an asset and the incurrence of a liability in accordance with GAAP as in effect on the date of the First Closing, notwithstanding any modifications or interpretive changes in GAAP that may become effective thereafter.

“Change of Control” is defined in Section 8.7.

“Closing” is defined in Section 3.

“Code” means the Internal Revenue Code of 1986 and the rules and regulations promulgated thereunder from time to time.

“Company” is defined in the first paragraph of this Agreement.

“Confidential Information” is defined in Section 20.

“Consolidated Debt” means, as at any date, all Indebtedness of the Company and its Subsidiaries outstanding on such date, determined on a consolidated basis in accordance with GAAP.

“Consolidated Net Worth” means, as at any date, consolidated shareholders’ equity (including preferred stock) of the Company and its Subsidiaries on such date, determined on a consolidated basis in accordance with GAAP provided that the computation of Consolidated Net Worth shall exclude Accumulated Other Comprehensive Income/Loss and market value of derivatives (FAS 133).

“Consolidated Total Assets” means, as of any date of determination, the total amount of all assets of the Company and its Subsidiaries, determined on a consolidated basis in accordance with GAAP excluding market value of derivatives (FAS 133).

“Consolidated Total Capitalization” means, as of any date of determination, the sum of Consolidated Net Worth and Indebtedness.

“Control” means the possession, directly or indirectly, of the power to direct or cause the direction of the management and policies of a Person, whether through the ownership of voting securities, by contract or otherwise; and the terms “Controlled” and “Controlling” shall have meanings correlative to the foregoing.

“Controlled Entity” means (a) any of the Subsidiaries of the Company and any of their or the Company’s respective Controlled Affiliates and (b) if the Company has a parent company, such parent company and its Controlled Affiliates.

    A-2

---

“Control Event” means:

    (i)    the execution by the Company or any of its Subsidiaries or Affiliates of any agreement or letter of intent with respect to any proposed transaction or event or series of transactions or events which, individually or in the aggregate, may reasonably be expected to result in a Change of Control,

    (ii)    the execution of any written agreement which, when fully performed by the parties thereto, would result in a Change of Control, or

    (iii)    the making of any written offer by any person (as such term is used in section 13(d) and section 14(d)(2) of the Exchange Act as in effect on the date of the First Closing) or related persons constituting a group (as such term is used in Rule 13d-5 under the Exchange Act as in effect on the date of the First Closing) to the holders of the common stock of the Company, which offer, if accepted by the requisite number of holders, would result in a Change of Control.

“Debt Rating” means the debt rating of the Notes as determined from time to time by any Acceptable Rating Agency. For the avoidance of doubt, the “Debt Rating” does not include any credit outlook provided by the Acceptable Rating Agency.

“Default” means an event or condition the occurrence or existence of which would, with the lapse of time or the giving of notice or both, become an Event of Default.

“Default Rate” means that rate of interest per annum that is the greater of (a) 2% above the rate of interest stated in clause (a) of the first paragraph of the applicable Notes or (b) 2% over the rate of interest publicly announced by Bank of America, N.A. in New York, New York as its “base” or “prime” rate.

“Disclosure Documents” is defined in Section 5.3.

“EDGAR” means the SEC’s Electronic Data Gathering, Analysis and Retrieval System or any successor SEC electronic filing system for such purposes.

“Environmental Laws” means any and all federal, state, local, and foreign statutes, laws, regulations, ordinances, rules, judgments, orders, decrees, permits, concessions, grants, franchises, licenses, agreements or governmental restrictions relating to pollution and the protection of the environment or the release of any materials into the environment, including those related to Hazardous Materials.

“ERISA” means the Employee Retirement Income Security Act of 1974 and the rules and regulations promulgated thereunder from time to time in effect.

“ERISA Affiliate” means any trade or business (whether or not incorporated) that is treated as a single employer together with the Company under section 414 of the Code.

    A-3

---

“Event of Default” is defined in Section 11.

“FATCA” means (a) sections 1471 through 1474 of the Code, as of the date of this Agreement (or any amended or successor version that is substantively comparable and not materially more onerous to comply with), together with any current or future regulations or official interpretations thereof, (b) any treaty, law or regulation of any other jurisdiction, or relating to an intergovernmental agreement between the United States of America and any other jurisdiction, which (in either case) facilitates the implementation of the foregoing clause (a), and (c) any agreements entered into pursuant to section 1471(b)(1) of the Code.

“First Closing” is defined in Section 3.

“Form 10-K” is defined in Section 7.1(b).

“Form 10-Q” is defined in Section 7.1(a).

“GAAP” means (a) generally accepted accounting principles as in effect from time to time in the United States of America and (b) for purposes of Section 9.6, with respect to any Subsidiary, generally accepted accounting principles (including International Financial Reporting Standards, as applicable) as in effect from time to time in the jurisdiction of organization of such Subsidiary.

“Governmental Authority” means

    (a)    the government of

    (i)    the United States of America or any state or other political subdivision thereof, or

    (ii)    any other jurisdiction in which the Company or any Subsidiary conducts all or any part of its business, or which asserts jurisdiction over any properties of the Company or any Subsidiary, or

    (b)    any entity exercising executive, legislative, judicial, regulatory or administrative functions of, or pertaining to, any such government.

“Governmental Official” means any governmental official or employee, employee of any government-owned or government-controlled entity, political party, any official of a political party, candidate for political office, official of any public international organization or anyone else acting in an official capacity.

“Guarantor” means each Person that has executed and delivered a Guaranty Agreement.

“Guaranty” means, with respect to any Person, any obligation (except the endorsement in the ordinary course of business of negotiable instruments for deposit or collection) of such Person guaranteeing or in effect guaranteeing any indebtedness, dividend or other obligation of

    A-4

---

any other Person in any manner, whether directly or indirectly, including obligations incurred through an agreement, contingent or otherwise, by such Person:

    (a)    to purchase such indebtedness or obligation or any property constituting security therefor;

    (b)    to advance or supply funds (i) for the purchase or payment of such indebtedness or obligation, or (ii) to maintain any working capital or other balance sheet condition or any income statement condition of any other Person or otherwise to advance or make available funds for the purchase or payment of such indebtedness or obligation;

    (c)    to lease properties or to purchase properties or services primarily for the purpose of assuring the owner of such indebtedness or obligation of the ability of any other Person to make payment of the indebtedness or obligation; or

    (d)    otherwise to assure the owner of such indebtedness or obligation against loss in respect thereof.

In any computation of the indebtedness or other liabilities of the obligor under any Guaranty, the indebtedness or other obligations that are the subject of such Guaranty shall be assumed to be direct obligations of such obligor.

“Guaranty Agreement” is defined in Section 9.7(a).

“Hazardous Materials” means any and all pollutants, toxic or hazardous wastes or other substances that might pose a hazard to health and safety, the removal of which may be required or the generation, manufacture, refining, production, processing, treatment, storage, handling, transportation, transfer, use, disposal, release, discharge, spillage, seepage or filtration of which is or shall be restricted, prohibited or penalized by any applicable law, including asbestos, urea formaldehyde foam insulation, polychlorinated biphenyls, petroleum, petroleum products, lead based paint, radon gas or similar restricted, prohibited or penalized substances.

“holder” means, with respect to any Note, the Person in whose name such Note is registered in the register maintained by the Company pursuant to Section 13.1, provided, however, that if such Person is a nominee, then for the purposes of Sections 7, 12, 17.2 and 18 and any related definitions in this Schedule A, “holder” shall mean the beneficial owner of such Note whose name and address appears in such register.

“Indebtedness” with respect to any Person means, at any time, without duplication,

    (a)    its liabilities for borrowed money and its redemption obligations in respect of mandatorily redeemable Preferred Stock;

    (b)    its liabilities appearing on its balance sheet in accordance with GAAP for the deferred purchase price of property acquired by such Person (excluding accounts payable arising in the ordinary course of business but including all liabilities created or

    A-5

---

arising under any conditional sale or other title retention agreement with respect to any such property);

    (c)    (i) all liabilities appearing on its balance sheet in accordance with GAAP in respect of Capital Leases and (ii) all liabilities which would appear on its balance sheet in accordance with GAAP in respect of Synthetic Leases assuming such Synthetic Leases were accounted for as Capital Leases;

    (d)    all liabilities for borrowed money secured by any Lien with respect to any property owned by such Person (whether or not it has assumed or otherwise become liable for such liabilities);

    (e)    all its liabilities in respect of letters of credit or instruments serving a similar function issued or accepted for its account by banks and other financial institutions (whether or not representing obligations for borrowed money);

    (f)    the aggregate Swap Termination Value of all Swap Contracts of such Person; and

    (g)    any Guaranty of such Person with respect to liabilities of a type described in any of clauses (a) through (f) hereof.

Indebtedness of any Person shall include all obligations of such Person of the character described in clauses (a) through (g) to the extent such Person remains legally liable in respect thereof notwithstanding that any such obligation is deemed to be extinguished under GAAP.

“INHAM Exemption” is defined in Section 6.2(e).

“Institutional Investor” means (a) any Purchaser of a Note, (b) any holder of a Note holding (together with one or more of its affiliates) more than 5% of the aggregate principal amount of the Notes then outstanding, (c) any bank, trust company, savings and loan association or other financial institution, any pension plan, any investment company, any insurance company, any broker or dealer, or any other similar financial institution or entity, regardless of legal form, and (d) any Related Fund of any holder of any Note.

“Investment Grade Rating” shall mean a rating equal to or higher than “BBB-” by S&P Global Ratings, a division of S&P Global Inc., or “Baa3” or higher by Moody’s Investors Service, Inc., or, in each case, an equivalent or better rating by any successor thereto, or any other nationally recognized statistical rating organization retained by the Company.

“Lien” means, with respect to any Person, any mortgage, lien, pledge, charge, security interest or other encumbrance, or any interest or title of any vendor, lessor, lender or other secured party to or of such Person under any conditional sale or other title retention agreement or Capital Lease, upon or with respect to any property or asset of such Person (including in the case of stock, shareholders agreements, voting trust agreements and all similar arrangements).

    A-6

---

“Make-Whole Amount” is defined in Section 8.6.

“Material” means material in relation to the business, operations, affairs, financial condition, assets or properties of the Company and its Subsidiaries taken as a whole.

“Material Adverse Effect” means a material adverse effect on (a) the business, operations, affairs, financial condition, assets or properties of the Company and its Subsidiaries taken as a whole, (b) the ability of the Company to perform its obligations under this Agreement and the Notes, (c) the ability of any Guarantor to perform its obligations under its Guaranty Agreement, or (d) the validity or enforceability of this Agreement, the Notes or any Guaranty Agreement.

“Material Credit Facility” means, as to the Company and its Subsidiaries, if any, any agreement(s) creating or evidencing indebtedness for borrowed money that the Company or any Subsidiary is party to, or in respect of which the Company or any Subsidiary is an obligor or otherwise provides a guarantee or other credit support (“Credit Facility”), in a principal amount outstanding or available for borrowing equal to or greater than the Threshold Amount (or the equivalent of such amount in the relevant currency of payment, determined as of the date of the closing of such facility based on the exchange rate of such other currency).

“Multiemployer Plan” means any Plan that is a “multiemployer plan” (as such term is defined in section 4001(a)(3) of ERISA).

“NAIC” means the National Association of Insurance Commissioners.

“Non-U.S. Plan” means any plan, fund or other similar program that (a) is established or maintained outside the United States of America by the Company or any Subsidiary primarily for the benefit of employees of the Company or one or more Subsidiaries residing outside the United States of America, which plan, fund or other similar program provides, or results in, retirement income, a deferral of income in contemplation of retirement or payments to be made upon termination of employment, and (b) is not subject to ERISA or the Code.

“Notes” is defined in Section 1.

“OBBB” means United States Public Law 119-21, An Act to provide for reconciliation pursuant to title II of H. Con. Res. 14 and the rules and regulations promulgated thereunder from time to time in effect.

“OFAC” means the Office of Foreign Assets Control of the United States Department of the Treasury.

“OFAC Sanctions Program” means any economic or trade sanction that OFAC is responsible for administering and enforcing. A list of OFAC Sanctions Programs may be found at https://ofac.treasury.gov/sanctions-programs-and-country-information.

    A-7

---

“Officer’s Certificate” means a certificate of a Senior Financial Officer or of any other officer of the Company whose responsibilities extend to the subject matter of such certificate.

“PBGC” means the Pension Benefit Guaranty Corporation referred to and defined in ERISA.

“Person” means an individual, partnership, corporation, limited liability company, association, trust, unincorporated organization, business entity or Governmental Authority.

“Plan” means an “employee benefit plan” (as defined in section 3(3) of ERISA) subject to Title I of ERISA that is or, within the preceding five years, has been established or maintained, or to which contributions are or, within the preceding five years, have been made or required to be made, by the Company or any ERISA Affiliate or with respect to which the Company or any ERISA Affiliate may have any liability.

“Preferred Stock” means any class of capital stock of a Person that is preferred over any other class of capital stock (or similar equity interests) of such Person as to the payment of dividends or the payment of any amount upon liquidation or dissolution of such Person.

“Priority Debt” means (without duplication), as of the date of any determination thereof, the sum of (i) all unsecured Indebtedness of Subsidiaries (including all Guaranties of Indebtedness of the Company) but excluding (x) unsecured Indebtedness owing to the Company or any other Subsidiary, (y) unsecured Indebtedness outstanding at the time such Person became a Subsidiary, provided that such Indebtedness shall have not been incurred in contemplation of such person becoming a Subsidiary, and (z) all unsecured Indebtedness of any Subsidiary that is a Guarantor, and (ii) all Indebtedness of the Company and its Subsidiaries secured by Liens other than Indebtedness secured by Liens permitted by subsections (a) through (n), inclusive, of Section 10.6.

“Private Rating Letter” means a letter issued by an Acceptable Rating Agency in connection with any private debt rating for the Notes, which (a) sets forth the Debt Rating for the Notes, (b) refers to the Private Placement Number issued by CUSIP Global Services in respect of the Notes, (c) addresses the likelihood of payment of both principal and interest on the Notes (which requirement shall be deemed satisfied if either (x) such letter includes confirmation that the rating reflects the Acceptable Rating Agency’s assessment of the Company’s ability to make timely payment of principal and interest on the Notes or a similar statement or (y) such letter is silent as to the Acceptable Rating Agency’s assessment of the likelihood of payment of both principal and interest and does not include any indication to the contrary), (d) includes such other information describing the relevant terms of the Notes as may be required from time to time by the SVO or any other U.S. Governmental Authority having jurisdiction over any holder of any Notes and (e) shall not be subject to confidentiality provisions or other restrictions which would prevent or limit the letter from being shared with the SVO or any other Governmental Authority having jurisdiction over any holder of any Notes.

“Private Rating Rationale Report” means, with respect to any Private Rating Letter, a report issued by an Acceptable Rating Agency in connection with such Private Rating Letter

    A-8

---

setting forth an analytical review of the Notes explaining the transaction structure, methodology relied upon, and, as appropriate, analysis of the credit, legal, and operational risks and mitigants supporting the assigned Private Rating for the Notes, in each case, on the letterhead of the Acceptable Rating Agency or its controlled website and generally consistent with the work product that an Acceptable Rating Agency would produce for a similar publicly rated security and otherwise in form and substance generally required by the SVO or any other U.S. Governmental Authority having jurisdiction over any holder of any Notes from time to time. Such report shall not be subject to confidentiality provisions or other restrictions which would prevent or limit the report from being shared with the SVO or any other U.S. Governmental Authority having jurisdiction over any holder of any Notes.

“property” or “properties” means, unless otherwise specifically limited, real or personal property of any kind, tangible or intangible, choate or inchoate.

“PTE” is defined in Section 6.2(a).

“Purchaser” or “Purchasers” means each of the purchasers that has executed and delivered this Agreement to the Company and such Purchaser’s successors and assigns (so long as any such assignment complies with Section 13.2), provided, however, that any Purchaser of a Note that ceases to be the registered holder or a beneficial owner (through a nominee) of such Note as the result of a transfer thereof pursuant to Section 13.2 shall cease to be included within the meaning of “Purchaser” of such Note for the purposes of this Agreement upon such transfer.

“Purchaser Schedule” means the Purchaser Schedule to this Agreement listing the Purchasers of the Notes and including their notice and payment information.

“QPAM Exemption” is defined in Section 6.2(d).

“Qualified Institutional Buyer” means any Person who is a “qualified institutional buyer” within the meaning of such term as set forth in Rule 144A(a)(1) under the Securities Act.

“Ratable Portion” means, with respect to any Note, an amount equal to the product of (x) the amount equal to the net proceeds being so applied to the prepayment of Senior Debt in accordance with Section 10.3(2), multiplied by (y) a fraction the numerator of which is the outstanding principal amount of such Note and the denominator of which is the aggregate principal amount of Senior Debt of the Company and its Subsidiaries being prepaid pursuant to Section 10.3(2).

“Ratings Period” is defined in Section 8.7.

“Related Fund” means, with respect to any holder of any Note, any fund or entity that (a) invests in Securities or bank loans, and (b) is advised or managed by such holder, the same investment advisor as such holder or by an affiliate of such holder or such investment advisor.

“Required Holders” means at any time (i) prior to the Second Closing, the Purchasers and (ii) on or after the Second Closing, the holders of at least a majority in principal amount of

    A-9

---

the Notes at the time outstanding (exclusive of Notes then owned by the Company or any of its Affiliates).

“Responsible Officer” means any Senior Financial Officer or any other officer of the Company with responsibility for the administration of the relevant portion of this Agreement.

“SEC” means the Securities and Exchange Commission of the United States of America.

“Second Closing” is defined in Section 3.

“Securities” or “Security” shall have the meaning specified in section 2(1) of the Securities Act.

“Securities Act” means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder from time to time in effect.

“Senior Debt” means, as of the date of any determination thereof, the total amount of all Indebtedness of the Company and its Subsidiaries determined on a consolidated basis in accordance with GAAP, other than Subordinated Debt.

“Senior Financial Officer” means the chief financial officer, senior vice president, finance, principal accounting officer, treasurer, controller, or comptroller of the Company.

“Series A Maturity Date” is defined in the first paragraph of each Series A Note.

“Series B Maturity Date” is defined in the first paragraph of each Series B Note.

“Significant Subsidiary” means at any time any Subsidiary that would at such time constitute a “significant subsidiary” (as such term is defined in Regulation S-X of the SEC as in effect on the date of the First Closing) of the Company.

“Source” is defined in Section 6.2.

“State Sanctions List” means a list that is adopted by any state Governmental Authority within the United States of America pertaining to Persons that engage in investment or other commercial activities in Iran or any other country that is a target of economic sanctions imposed under U.S. Economic Sanctions Laws.

“Subordinated Debt” means all unsecured Indebtedness of the Company which shall contain or have applicable thereto subordination provisions providing for the subordination thereof to other unsecured Indebtedness of the Company.

“Subsidiary” means, as to any Person, any other Person in which such first Person or one or more of its Subsidiaries or such first Person and one or more of its Subsidiaries owns sufficient equity or voting interests to enable it or them (as a group) ordinarily, in the absence of contingencies, to elect a majority of the directors (or Persons performing similar functions) of

    A-10

---

such second Person, and any partnership or joint venture if more than a 50% interest in the profits or capital thereof is owned by such first Person or one or more of its Subsidiaries or such first Person and one or more of its Subsidiaries (unless such partnership or joint venture can and does ordinarily take major business actions without the prior approval of such Person or one or more of its Subsidiaries). Unless the context otherwise clearly requires, any reference to a “Subsidiary” is a reference to a Subsidiary of the Company.

“Substantial Part” is defined in Section 10.3.

“Substitute Purchaser” is defined in Section 21.

“SVO” means the Securities Valuation Office of the NAIC.

“Swap Contract” means (a) any and all interest rate swap transactions, basis swap transactions, basis swaps, credit derivative transactions, forward rate transactions, commodity swaps, commodity options, forward commodity contracts, equity or equity index swaps or options, bond or bond price or bond index swaps or options or forward foreign exchange transactions, cap transactions, floor transactions, currency options, spot contracts or any other similar transactions or any of the foregoing (including any options to enter into any of the foregoing), and (b) any and all transactions of any kind, and the related confirmations, which are subject to the terms and conditions of, or governed by, any form of master agreement published by the International Swaps and Derivatives Association, Inc. or any International Foreign Exchange Master Agreement.

“Swap Termination Value” means, in respect of any one or more Swap Contracts, after taking into account the effect of any legally enforceable netting agreement relating to such Swap Contracts, (a) for any date on or after the date such Swap Contracts have been closed out and termination value(s) determined in accordance therewith, such termination value(s), and (b) for any date prior to the date referenced in clause (a), the amounts(s) determined as the mark-to-market values(s) for such Swap Contracts, as determined based upon one or more mid-market or other readily available quotations provided by any recognized dealer in such Swap Contracts.

“Synthetic Lease” means, at any time, any lease (including leases that may be terminated by the lessee at any time) of any property (a) that is accounted for as an operating lease under GAAP and (b) in respect of which the lessee retains or obtains ownership of the property so leased for U.S. federal income tax purposes, other than any such lease under which such Person is the lessor.

“Threshold Amount” means the lesser of 2% of Consolidated Total Assets or $50,000,000 (or its equivalent in the relevant currency of payment).

“United States Person” has the meaning set forth in section 7701(a)(30) of the Code.

“USA PATRIOT Act” means United States Public Law 107-56, Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct

    A-11

---

Terrorism (USA PATRIOT ACT) Act of 2001 and the rules and regulations promulgated thereunder from time to time in effect.

“U.S. Economic Sanctions Laws” means those laws, executive orders, enabling legislation or regulations administered and enforced by the United States pursuant to which economic sanctions have been imposed on any Person, entity, organization, country or regime, including the Trading with the Enemy Act, the International Emergency Economic Powers Act, the Iran Sanctions Act, the Sudan Accountability and Divestment Act and any other OFAC Sanctions Program.

“Wholly-Owned Subsidiary” means, at any time, any Subsidiary all of the equity interests (except directors’ qualifying shares) and voting interests of which are owned by any one or more of the Company and the Company’s other Wholly-Owned Subsidiaries at such time.

    A-12

---

[Form of Series A Note]

Illinois Commerce Commission ID Nos.: Ill. C.C. No. 7057

Ameren Transmission Company of Illinois

5.83% Senior Note, Series A, due August 6, 2041

No. RA-[_____]    [Date]

$[_______]    PPN 02361@AF4

For Value Received, the undersigned, Ameren Transmission Company of Illinois (herein called the “Company”), a corporation organized and existing under the laws of the State of Illinois, hereby promises to pay to [____________], or registered assigns, the principal sum of [_____________________] Dollars (or so much thereof as shall not have been prepaid) on August 6, 2041 (the “Series A Maturity Date”), with interest (computed on the basis of a 360-day year of twelve 30-day months) (a) on the unpaid balance hereof at the rate of 5.83% per annum from the date hereof, payable semiannually, on the 6th day of February and August in each year, commencing with the February or August next succeeding the date hereof, and on the Series A Maturity Date, until the principal hereof shall have become due and payable, and (b) to the extent permitted by law, (x) on any overdue payment of interest and (y) during the continuance of an Event of Default, on such unpaid balance and on any overdue payment of any Make-Whole Amount, at a rate per annum from time to time equal to the greater of (i) 7.83% or (ii) 2.0% over the rate of interest publicly announced by Bank of America, N.A. from time to time in New York, New York as its “base” or “prime” rate, payable semiannually as aforesaid (or, at the option of the registered holder hereof, on demand).

Payments of principal of, interest on and any Make-Whole Amount with respect to this Note are to be made in lawful money of the United States of America in New York, New York or at such other place as the Company shall have designated by written notice to the holder of this Note as provided in the Note Purchase Agreement referred to below.

This Note is one of a series of Senior Notes (herein called the “Notes”) issued pursuant to the Note Purchase Agreement, dated as of August 6, 2026 (as from time to time amended, the “Note Purchase Agreement”), between the Company and the respective Purchasers named therein and is entitled to the benefits thereof. Each holder of this Note will be deemed, by its acceptance hereof, to have (i) agreed to the confidentiality provisions set forth in Section 20 of the Note Purchase Agreement and (ii) made the representation set forth in Section 6.2 of the Note Purchase Agreement. Unless otherwise indicated, capitalized terms used in this Note shall have the respective meanings ascribed to such terms in the Note Purchase Agreement.

This Note is a registered Note and, as provided in the Note Purchase Agreement, upon surrender of this Note for registration of transfer accompanied by a written instrument of transfer duly executed by the registered holder hereof or such holder’s attorney duly authorized in writing, a new Note for a like principal amount will be issued to, and registered in the name of,

Schedule 1(a)
(to Note Purchase Agreement)

---

the transferee. Prior to due presentment for registration of transfer, the Company may treat the Person in whose name this Note is registered as the owner hereof for the purpose of receiving payment and for all other purposes, and the Company will not be affected by any notice to the contrary.

This Note is subject to optional prepayment, in whole or from time to time in part, at the times and on the terms specified in the Note Purchase Agreement, but not otherwise.

If an Event of Default occurs and is continuing, the principal of this Note may be declared or otherwise become due and payable in the manner, at the price (including any applicable Make-Whole Amount) and with the effect provided in the Note Purchase Agreement.

This Note shall be construed and enforced in accordance with, and the rights of the Company and the holder of this Note shall be governed by, the law of the State of New York excluding choice-of-law principles of the law of such State that would permit the application of the laws of a jurisdiction other than such State.

    Ameren Transmission Company of Illinois

    By ________________________________        

    Name:

    Title:

1(a)-2

---

[Form of Series B Note]

Illinois Commerce Commission ID Nos.: Ill. C.C. No. 7058

Ameren Transmission Company of Illinois

6.24% Senior Note, Series B, due January 28, 2054

No. RB-[_____]    [Date]

$[_______]    PPN 02361@AG2

For Value Received, the undersigned, Ameren Transmission Company of Illinois (herein called the “Company”), a corporation organized and existing under the laws of the State of Illinois, hereby promises to pay to [____________], or registered assigns, the principal sum of [_____________________] Dollars (or so much thereof as shall not have been prepaid) on January 28, 2054 (the “Series B Maturity Date”), with interest (computed on the basis of a 360-day year of twelve 30-day months) (a) on the unpaid balance hereof at the rate of 6.24% per annum from the date hereof, payable semiannually, on the 28th day of January and July in each year, commencing with the January or July next succeeding the date hereof, and on the Series B Maturity Date, until the principal hereof shall have become due and payable, and (b) to the extent permitted by law, (x) on any overdue payment of interest and (y) during the continuance of an Event of Default, on such unpaid balance and on any overdue payment of any Make-Whole Amount, at a rate per annum from time to time equal to the greater of (i) 8.24% or (ii) 2.0% over the rate of interest publicly announced by Bank of America, N.A. from time to time in New York, New York as its “base” or “prime” rate, payable semiannually as aforesaid (or, at the option of the registered holder hereof, on demand).

Payments of principal of, interest on and any Make-Whole Amount with respect to this Note are to be made in lawful money of the United States of America in New York, New York or at such other place as the Company shall have designated by written notice to the holder of this Note as provided in the Note Purchase Agreement referred to below.

This Note is one of a series of Senior Notes (herein called the “Notes”) issued pursuant to the Note Purchase Agreement, dated as of August 6, 2026 (as from time to time amended, the “Note Purchase Agreement”), between the Company and the respective Purchasers named therein and is entitled to the benefits thereof. Each holder of this Note will be deemed, by its acceptance hereof, to have (i) agreed to the confidentiality provisions set forth in Section 20 of the Note Purchase Agreement and (ii) made the representation set forth in Section 6.2 of the Note Purchase Agreement. Unless otherwise indicated, capitalized terms used in this Note shall have the respective meanings ascribed to such terms in the Note Purchase Agreement.

This Note is a registered Note and, as provided in the Note Purchase Agreement, upon surrender of this Note for registration of transfer accompanied by a written instrument of transfer duly executed by the registered holder hereof or such holder’s attorney duly authorized in writing, a new Note for a like principal amount will be issued to, and registered in the name of,

Schedule 1(b)
(to Note Purchase Agreement)

---

the transferee. Prior to due presentment for registration of transfer, the Company may treat the Person in whose name this Note is registered as the owner hereof for the purpose of receiving payment and for all other purposes, and the Company will not be affected by any notice to the contrary.

This Note is subject to optional prepayment, in whole or from time to time in part, at the times and on the terms specified in the Note Purchase Agreement, but not otherwise.

If an Event of Default occurs and is continuing, the principal of this Note may be declared or otherwise become due and payable in the manner, at the price (including any applicable Make-Whole Amount) and with the effect provided in the Note Purchase Agreement.

This Note shall be construed and enforced in accordance with, and the rights of the Company and the holder of this Note shall be governed by, the law of the State of New York excluding choice-of-law principles of the law of such State that would permit the application of the laws of a jurisdiction other than such State.

    Ameren Transmission Company of Illinois

    By ________________________________        

    Name:

    Title:

1(b)-2

---

Ameren Transmission Company of Illinois

Information Relating to Purchasers

Name of Purchaser

Series of Notes

Principal Amount of Notes to be Purchased

American General Life Insurance Company

A

$25,000,000

American General Life Insurance Company

A

$10,000,000

American General Life Insurance Company

B

$20,000,000

Teachers Insurance and Annuity Association of America

A

$35,000,000

B

$20,000,000

State Farm Life Insurance Company

A

$28,000,000

State Farm Insurance Companies Employee Retirement Trust

A

$5,500,000

State Farm Life and Accident Assurance Company

A

$1,500,000

Metropolitan Tower Life Insurance Company

B

$10,000,000

Metropolitan Tower Life Insurance Company

B

$6,600,000

Metlife Reinsurance Company of Hamilton, Ltd.

B

$5,100,000

Metlife Reinsurance Company of Hamilton, Ltd.

B

$5,000,000

MetLife Insurance Co. of Korea, Ltd.

B

$3,300,000

Berkshire Life Insurance Company of America

A

$15,000,000

The Guardian Life Insurance Company of America

A

$10,000,000

Thrivent Financial for Lutherans

B

$17,000,000

---

The Northwestern Mutual Life Insurance Company

B

$15,872,000

The Northwestern Mutual Life Insurance Company for its Group Annuity Separate Account

B

$128,000

RGA Americas Reinsurance Company, LTD

B

$4,800,000

RGA Americas Reinsurance Company, LTD

B

$4,800,000

RGA Americas Reinsurance Company, LTD

B

$3,200,000

RGA Reinsurance Company

B

$1,600,000

RGA Reinsurance Company Barbados LTD

B

$1,600,000

Modern Woodmen of America

A

$6,000,000

B

$6,000,000

American United Life Insurance Company

A

$4,000,000

The State Life Insurance Company

B

$3,000,000

Unum Life Insurance Company of America

B

$7,000,000

John Hancock Life Insurance Company (U.S.A.)

B

$5,000,000

John Hancock Life & Health Insurance Company

B

$1,000,000

CMFG Life Insurance Company

B

$6,000,000

Ameritas Life Insurance Corp.

B

$4,500,000

Ameritas Life Insurance Corp. of New York

B

$500,000

Liberty National Life Insurance Company

B

$4,000,000

Life Insurance Company of the Southwest

B

$3,000,000

Southern Farm Bureau Life Insurance Company

B

$1,000,000

Exhibit 31.1

RULE 13a-14(a)/15d-14(a) CERTIFICATION

OF PRINCIPAL EXECUTIVE OFFICER OF AMEREN CORPORATION

(required by Section 302 of the Sarbanes-Oxley Act of 2002)

    I, Martin J. Lyons, Jr., certify that:

    1.    I have reviewed this report on Form 10-Q for the quarterly period ended September 30, 2026 of Ameren Corporation;

    2.    Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

    3.    Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

    4.    The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

    5.    The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: November 6, 2026

/s/ Martin J. Lyons, Jr.
Martin J. Lyons, Jr. Chairman, President and Chief Executive Officer (Principal Executive Officer)

Exhibit 31.2

RULE 13a-14(a)/15d-14(a) CERTIFICATION

OF PRINCIPAL FINANCIAL OFFICER OF AMEREN CORPORATION

(required by Section 302 of the Sarbanes-Oxley Act of 2002)

    I, Leonard P. Singh, certify that:

    1.    I have reviewed this report on Form 10-Q for the quarterly period ended September 30, 2026 of Ameren Corporation;

    2.    Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

    3.    Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

    4.    The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

    5.    The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: November 6, 2026

/s/ Leonard P. Singh
Leonard P. Singh Executive Vice President and Chief Financial Officer (Principal Financial Officer)

Exhibit 31.3

RULE 13a-14(a)/15d-14(a) CERTIFICATION

OF PRINCIPAL EXECUTIVE OFFICER AND PRINCIPAL FINANCIAL OFFICER OF UNION ELECTRIC COMPANY

(required by Section 302 of the Sarbanes-Oxley Act of 2002)

    I, Aaron P. Melda, certify that:

    1.    I have reviewed this report on Form 10-Q for the quarterly period ended September 30, 2026 of Union Electric Company;

    2.    Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

    3.    Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

    4.    The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

    5.    The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: November 6, 2026

/s/ Aaron P. Melda
Aaron P. Melda Chairman and President (Principal Executive Officer)

Exhibit 31.4

RULE 13a-14(a)/15d-14(a) CERTIFICATION

OF PRINCIPAL FINANCIAL OFFICER OF UNION ELECTRIC COMPANY

(required by Section 302 of the Sarbanes-Oxley Act of 2002)

    I, Leonard P. Singh, certify that:

    1.    I have reviewed this report on Form 10-Q for the quarterly period ended September 30, 2026 of Union Electric Company;

    2.    Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

    3.    Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

    4.    The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

    5.    The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: November 6, 2026

/s/ Leonard P. Singh
Leonard P. Singh Executive Vice President and Chief Financial Officer (Principal Financial Officer)

Exhibit 31.5

RULE 13a-14(a)/15d-14(a) CERTIFICATION

OF PRINCIPAL EXECUTIVE OFFICER OF AMEREN ILLINOIS COMPANY

(required by Section 302 of the Sarbanes-Oxley Act of 2002)

    I, Patrick E. Smith Sr., certify that:

    1.    I have reviewed this report on Form 10-Q for the quarterly period ended September 30, 2026 of Ameren Illinois Company;

    2.    Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

    3.    Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

    4.    The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

    5.    The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: November 6, 2026

/s/ Patrick E. Smith Sr.
Patrick E. Smith Sr. Chairman and President (Principal Executive Officer)

Exhibit 31.6

RULE 13a-14(a)/15d-14(a) CERTIFICATION

OF PRINCIPAL FINANCIAL OFFICER OF AMEREN ILLINOIS COMPANY

(required by Section 302 of the Sarbanes-Oxley Act of 2002)

    I, Leonard P. Singh, certify that:

    1.    I have reviewed this report on Form 10-Q for the quarterly period ended September 30, 2026 of Ameren Illinois Company;

    2.    Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

    3.    Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

    4.    The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

    5.    The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: November 6, 2026

/s/ Leonard P. Singh
Leonard P. Singh Executive Vice President and Chief Financial Officer (Principal Financial Officer)

Exhibit 32.1

SECTION 1350 CERTIFICATION OF THE PRINCIPAL EXECUTIVE OFFICER

AND THE PRINCIPAL FINANCIAL OFFICER OF

AMEREN CORPORATION

(required by Section 906 of the Sarbanes-Oxley Act of 2002)

In connection with the report on Form 10-Q for the quarterly period ended September 30, 2026 of Ameren Corporation (the “Registrant”) as filed by the Registrant with the Securities and Exchange Commission on the date hereof (the "Form 10-Q”), each undersigned officer of the Registrant does hereby certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that:

(1)The Form 10-Q fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or 78o(d)); and

(2)The information contained in the Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

Date: November 6, 2026

/s/ Martin J. Lyons, Jr.
Martin J. Lyons, Jr. Chairman, President and Chief Executive Officer (Principal Executive Officer)

/s/ Leonard P. Singh
Leonard P. Singh Executive Vice President and Chief Financial Officer (Principal Financial Officer)

Exhibit 32.2

SECTION 1350 CERTIFICATION OF THE PRINCIPAL EXECUTIVE OFFICER

AND THE PRINCIPAL FINANCIAL OFFICER OF

UNION ELECTRIC COMPANY

(required by Section 906 of the Sarbanes-Oxley Act of 2002)

In connection with the report on Form 10-Q for the quarterly period ended September 30, 2026 of Union Electric Company (the “Registrant”) as filed by the Registrant with the Securities and Exchange Commission on the date hereof (the "Form 10-Q"), each undersigned officer of the Registrant does hereby certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that:

(1)The Form 10-Q fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or 78o(d)); and

(2)The information contained in the Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

Date: November 6, 2026

/s/ Aaron P. Melda
Aaron P. Melda Chairman and President (Principal Executive Officer)

/s/ Leonard P. Singh
Leonard P. Singh Executive Vice President and Chief Financial Officer (Principal Financial Officer)

Exhibit 32.3

SECTION 1350 CERTIFICATION OF THE PRINCIPAL EXECUTIVE OFFICER

AND THE PRINCIPAL FINANCIAL OFFICER OF

AMEREN ILLINOIS COMPANY

(required by Section 906 of the Sarbanes-Oxley Act of 2002)

In connection with the report on Form 10-Q for the quarterly period ended September 30, 2026 of Ameren Illinois Company (the “Registrant”) as filed by the Registrant with the Securities and Exchange Commission on the date hereof (the "Form 10-Q"), each undersigned officer of the Registrant does hereby certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that:

(1)The Form 10-Q fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or 78o(d)); and

(2)The information contained in the Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

Date: November 6, 2026

/s/ Patrick E. Smith Sr.
Patrick E. Smith Sr. Chairman and President (Principal Executive Officer)

/s/ Leonard P. Singh
Leonard P. Singh Executive Vice President and Chief Financial Officer (Principal Financial Officer)