CENX · Century Aluminum Co

Represents annual grant of restricted stock units ("RSUs"), all of which vest in full on the earlier of (i) the 12-month anniversary of the grant date, (ii) the date of the Issuer's next regular annual meeting of stockholders, or (iii) the occurrence of certain other events in accordance with the terms of the award.

Includes shares of common stock issuable pursuant to vested RSUs, the settlement of which have been deferred pursuant to an annual deferral election previously made by the Reporting Person.

Represents annual grant of restricted stock units ("RSUs"), all of which vested on the date of grant.

Includes shares of common stock issuable pursuant to vested RSUs, the settlement of which have been deferred pursuant to an annual deferral election previously made by the Reporting Person.

Represents shares withheld by the Issuer upon vesting of the RSUs to satisfy tax obligations.

Represents annual grant of restricted stock units ("RSUs"), all of which vest in full on the earlier of (i) the 12-month anniversary of the grant date, (ii) the date of the Issuer's next regular annual meeting of stockholders, or (iii) the occurrence of certain other events in accordance with the terms of the award.

Includes shares of common stock issuable pursuant to vested RSUs, the settlement of which have been deferred pursuant to an annual deferral election previously made by the Reporting Person.

Represents annual grant of restricted stock units ("RSUs"), all of which vested on the date of grant.

Represents annual grant of restricted stock units ("RSUs"), all of which vest in full on the earlier of (i) the 12-month anniversary of the grant date, (ii) the date of the Issuer's next regular annual meeting of stockholders, or (iii) the occurrence of certain other events in accordance with the terms of the award.

Includes shares of common stock issuable pursuant to vested RSUs, the settlement of which have been deferred pursuant to an annual deferral election previously made by the Reporting Person.

The price reported above reflects the weighted average sale price for the shares which were sold in multiple transactions at prices ranging from $50.50 to $50.64, inclusive. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the specific number of shares and prices at which the transactions were effected.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 20, 2025 (the 'Trading Plan'). There are no additional shares available for sale under the Trading Plan and, as such, the Trading Plan is now complete.

The price reported above reflects the weighted average sale price for the shares which were sold in multiple transactions at prices ranging from $54.08 to $56.80, inclusive. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the specific number of shares and prices at which the transactions were effected.

Shares held in a self-settled, revocable trust for which the Reporting Person serves as trustee.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

The price reported above reflects the weighted average sale price for the shares which were sold in multiple transactions at prices ranging from $56.25 to $56.75, inclusive. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the specific number of shares and prices at which the transactions were effected.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

The Common Stock reported on Line 1 of Table I is held directly by Glencore International AG. Glencore International AG is wholly-owned by Glencore plc, which may be deemed an indirect beneficial owner of the securities held by Glencore AG and Glencore International AG.

The price reported above reflects the weighted average sale price for the shares which were sold in multiple transactions at prices ranging from $56.15 to $56.50, inclusive. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the specific number of shares and prices at which the transactions were effected.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

The price reported above reflects the weighted average sale price for the shares which were sold in multiple transactions at prices ranging from $52.50 to $52.75, inclusive. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the specific number of shares and prices at which the transactions were effected.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

The price reported above reflects the weighted average sale price for the shares which were sold in multiple transactions at prices ranging from $51.28 to $53.21, inclusive. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the specific number of shares and prices at which the transactions were effected.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

The price reported above reflects the weighted average sale price for the shares which were sold in multiple transactions at prices ranging from $49.91 to $52.01, inclusive. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the specific number of shares and prices at which the transactions were effected.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of RSUs previously granted to the Reporting Person on February 9, 2023.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 20, 2025.

The price reported above reflects the weighted average sale price for the shares which were sold in multiple transactions at prices ranging from $46.64 to $49.11, inclusive. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the specific number of shares and prices at which the transactions were effected.

Shares held in a self-settled, revocable trust for which the Reporting Person serves as trustee.

Represents shares transferred by the Reporting Person to a self-settled, revocable trust for estate planning purposes for which the Reporting Person serves as trustee.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

Represents shares transferred by the Reporting Person to a self-settled, revocable trust for estate planning purposes for which the Reporting Person serves as trustee.

Represents RSUs granted to the Reporting Person in connection with the Issuer's 2026-2028 Long-Term Incentive Plan under Rule 16b-3(d), all of which will vest on December 31, 2028, subject to the Plan's terms and conditions.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

Represents RSUs granted to the Reporting Person in connection with the Issuer's 2026-2028 Long-Term Incentive Plan under Rule 16b-3(d), all of which will vest on December 31, 2028, subject to the Plan's terms and conditions.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

Represents RSUs granted to the Reporting Person in connection with the Issuer's 2026-2028 Long-Term Incentive Plan under Rule 16b-3(d), all of which will vest on December 31, 2028, subject to the Plan's terms and conditions.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

Represents RSUs granted to the Reporting Person in connection with the Issuer's 2026-2028 Long-Term Incentive Plan under Rule 16b-3(d), all of which will vest on December 31, 2028, subject to the Plan's terms and conditions.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

Represents RSUs granted to the Reporting Person in connection with the Issuer's 2026-2028 Long-Term Incentive Plan under Rule 16b-3(d), all of which will vest on December 31, 2028, subject to the Plan's terms and conditions.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

Represents RSUs granted to the Reporting Person in connection with the Issuer's 2026-2028 Long-Term Incentive Plan under Rule 16b-3(d), all of which will vest on December 31, 2028, subject to the Plan's terms and conditions.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

Represents RSUs granted to the Reporting Person in connection with the Issuer's 2026-2028 Long-Term Incentive Plan under Rule 16b-3(d), all of which will vest on December 31, 2028, subject to the Plan's terms and conditions.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

Represents RSUs granted to the Reporting Person in connection with the Issuer's 2026-2028 Long-Term Incentive Plan under Rule 16b-3(d), all of which will vest on December 31, 2028, subject to the Plan's terms and conditions.

Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of RSUs previously granted to the Reporting Person on January 1, 2023.

Represents shares of common stock acquired by the Reporting Person upon the vesting of PSUs granted in connection with the Issuer's 2023-2025 Long-Term Incentive Plan under Rule 16b-3(d).

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of RSUs previously granted to the Reporting Person on January 1, 2023.

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of PSUs granted to the Reporting Person.

Represents shares of common stock acquired by the Reporting Person upon the vesting of PSUs granted in connection with the Issuer's 2023-2025 Long-Term Incentive Plan under Rule 16b-3(d).

Represents shares of common stock acquired by the Reporting Person upon the vesting of PSUs granted in connection with the Issuer's 2023-2025 Long-Term Incentive Plan under Rule 16b-3(d).

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of PSUs granted to the Reporting Person.

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of RSUs previously granted to the Reporting Person on January 1, 2023.

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of RSUs previously granted to the Reporting Person on January 1, 2023.

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of PSUs granted to the Reporting Person.

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of RSUs previously granted to the Reporting Person on January 1, 2023.

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of PSUs granted to the Reporting Person.

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of RSUs previously granted to the Reporting Person on January 1, 2023.

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of RSUs previously granted to the Reporting Person on January 1, 2023.

Represents shares of common stock acquired by the Reporting Person upon the vesting of PSUs granted in connection with the Issuer's 2023-2025 Long-Term Incentive Plan under Rule 16b-3(d).

Represents shares of common stock acquired by the Reporting Person upon the vesting of PSUs granted in connection with the Issuer's 2023-2025 Long-Term Incentive Plan under Rule 16b-3(d).

Represents shares of common stock acquired by the Reporting Person upon the vesting of PSUs granted in connection with the Issuer's 2023-2025 Long-Term Incentive Plan under Rule 16b-3(d).

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of PSUs granted to the Reporting Person.

Represents shares of common stock acquired by the Reporting Person upon the vesting of PSUs granted in connection with the Issuer's 2023-2025 Long-Term Incentive Plan under Rule 16b-3(d).

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of RSUs previously granted to the Reporting Person on January 1, 2023.

Shares withheld by the Issuer to satisfy tax obligations in connection with the vesting of PSUs granted to the Reporting Person.