CWST

Represents a gift of shares to the Nagle-Green Charitable Fund at Fidelity.

Represents the award of restricted stock units (RSUs) under the Casella Waste Systems, Inc. Amended and Restated 2016 Incentive Plan. Each RSU represents a contingent right to receive one share of Casella's Class A Common Stock. The RSUs will vest in full on June 4, 2027.

Represents the award of restricted stock units (RSUs) under the Casella Waste Systems, Inc. Amended and Restated 2016 Incentive Plan. Each RSU represents a contingent right to receive one share of Casella's Class A Common Stock. The RSUs will vest in full on June 4, 2027.

Represents the award of restricted stock units (RSUs) under the Casella Waste Systems, Inc. Amended and Restated 2016 Incentive Plan. Each RSU represents a contingent right to receive one share of Casella's Class A Common Stock. The RSUs will vest in full on June 4, 2027.

Represents the award of restricted stock units (RSUs) under the Casella Waste Systems, Inc. Amended and Restated 2016 Incentive Plan. Each RSU represents a contingent right to receive one share of Casella's Class A Common Stock. The RSUs will vest in full on June 4, 2027.

Represents the award of restricted stock units (RSUs) under the Casella Waste Systems, Inc. Amended and Restated 2016 Incentive Plan. Each RSU represents a contingent right to receive one share of Casella's Class A Common Stock. The RSUs will vest in full on June 4, 2027.

Represents the award of restricted stock units (RSUs) under the Casella Waste Systems, Inc. Amended and Restated 2016 Incentive Plan. Each RSU represents a contingent right to receive one share of Casella's Class A Common Stock. The RSUs will vest in full on June 4, 2027.

Represents the award of restricted stock units (RSUs) under the Casella Waste Systems, Inc. Amended and Restated 2016 Incentive Plan. Each RSU represents a contingent right to receive one share of Casella's Class A Common Stock. The RSUs will vest in full on June 4, 2027.

Represents the award of restricted stock units (RSUs) under the Casella Waste Systems, Inc. Amended and Restated 2016 Incentive Plan. Each RSU represents a contingent right to receive one share of Casella's Class A Common Stock. The RSUs will vest in full on June 4, 2027.

Represents a gift of shares to the Spousal Lifetime Access Trust ("SLAT") for the benefit of Mr. Casella's spouse. Mr. Casella's spouse is the trustee of the SLAT.

Held by the SLAT for the benefit of Mr. Casella's spouse. Mr. Casella's spouse is the trustee of the SLAT. Mr. Casella disclaims beneficial ownership of the securities indicated to the extent to which he does not have an actual pecuniary interest in such securities.

Represents a gift of shares to the Spousal Lifetime Access Trust ("SLAT 2") for the benefit of Mr. Casella. Mr. Casella is the trustee of the SLAT 2.

Held by Mr. Casella's spouse. Mr. Casella disclaims beneficial ownership of the securities indicated to the extent to which he does not have an actual pecuniary interest in such securities.

Represents a gift of shares to the Spousal Lifetime Access Trust ("SLAT") for the benefit of Mr. Casella's spouse. Mr. Casella's spouse is the trustee of the SLAT.

Represents a gift of shares to the Spousal Lifetime Access Trust ("SLAT 2") for the benefit of Mr. Casella. Mr. Casella is the trustee of the SLAT 2.

Held by the SLAT 2 for the benefit of Mr. Casella. Mr. Casella is the trustee of the SLAT 2.

Represents the weighted average sales price for shares sold in multiple transactions, ranging from $87.45 to $87.69. Upon request of the staff of the Securities and Exchange Commission, the issuer or a security holder of the issuer, the reporting person will provide full information regarding the number of shares sold at each separate price.

Represents the weighted average sales price for shares sold in multiple transactions, ranging from $89.00 to $89.27. Upon request of the staff of the Securities and Exchange Commission, the issuer or a security holder of the issuer, the reporting person will provide full information regarding the number of shares sold at each separate price.

Represents the weighted average sales price for shares sold in multiple transactions, ranging from $90.07 to $90.09. Upon request of the staff of the Securities and Exchange Commission, the issuer or a security holder of the issuer, the reporting person will provide full information regarding the number of shares sold at each separate price.

Represents a gift of shares to the Spousal Lifetime Access Trust for the benefit of Mr. Casella's spouse ("SLAT"). Mr. Casella's spouse is the trustee of the SLAT. The original Form 4 filed on March 24, 2026 (the "Original Form 4") incorrectly reported the gift as a transfer of the shares to the Spousal Lifetime Access Trust for the benefit of Mr. Casella ("SLAT 2"). This amendment reflects the transfer of the shares to the SLAT and the correct amount of securities beneficially owned by the SLAT following the transaction reported in the Original Form 4.

Held by the SLAT. Mr. Casella's spouse is the trustee of the SLAT. Mr. Casella disclaims beneficial ownership of the securities indicated to the extent to which he does not have an actual pecuniary interest in such securities.

Represents a gift of shares to the SLAT 2. Mr. Casella is the trustee of the SLAT 2. The Original Form 4 incorrectly reported the gift as a transfer of the shares to the SLAT. This amendment reflects the transfer of the shares to the SLAT 2 and the correct amount of securities beneficially owned by the SLAT 2 following the transaction reported in the Original Form 4.

Held by the SLAT 2. Mr. Casella is the trustee of SLAT 2.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of RSUs previously granted to the reporting person. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 22, 2023 and does not represent a discretionary sale by the reporting person.

Represents the weighted average sales price for shares sold in multiple transactions, ranging from $87.77 to $87.85. Upon request of the staff of the Securities and Exchange Commission, the issuer or a security holder of the issuer, the reporting person will provide full information regarding the number of shares sold at each separate price.

Represents the award of Restricted Stock Units (RSUs) under the Casella Waste Systems, Inc. Amended and Restated 2016 Incentive Plan. Each RSU represents a contingent right to receive one share of Casella's Class A Common Stock. RSUs vest in three equal annual installments beginning on March 12, 2027.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of RSUs previously granted to the reporting person. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 2, 2023 and does not represent a discretionary sale by the reporting person.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of RSUs previously granted to the reporting person. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on November 16, 2023 and does not represent a discretionary sale by the reporting person.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of RSUs previously granted to the reporting person. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 2, 2023 and does not represent a discretionary sale by the reporting person.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of RSUs previously granted to the reporting person. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 2, 2023 and does not represent a discretionary sale by the reporting person.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of RSUs previously granted to the reporting person. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 2, 2023 and does not represent a discretionary sale by the reporting person.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of RSUs previously granted to the reporting person. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 2, 2023 and does not represent a discretionary sale by the reporting person.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of RSUs previously granted to the reporting person. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 22, 2023 and does not represent a discretionary sale by the reporting person.

Represents the award of Restricted Stock Units (RSUs) under the Casella Waste Systems, Inc. Amended and Restated 2016 Incentive Plan. Each RSU represents a contingent right to receive one share of Casella's Class A Common Stock. RSUs vest in three equal annual installments beginning on March 12, 2027.

Represents the award of Restricted Stock Units (RSUs) under the Casella Waste Systems, Inc. Amended and Restated 2016 Incentive Plan. Each RSU represents a contingent right to receive one share of Casella's Class A Common Stock. RSUs vest in three equal annual installments beginning on March 12, 2027.

Represents the award of Restricted Stock Units (RSUs) under the Casella Waste Systems, Inc. Amended and Restated 2016 Incentive Plan. Each RSU represents a contingent right to receive one share of Casella's Class A Common Stock. RSUs vest in three equal annual installments beginning on March 12, 2027.

Represents the award of Restricted Stock Units (RSUs) under the Casella Waste Systems, Inc. Amended and Restated 2016 Incentive Plan. Each RSU represents a contingent right to receive one share of Casella's Class A Common Stock. RSUs vest in three equal annual installments beginning on March 12, 2027.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of RSUs previously granted to the reporting person. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 2, 2023 and does not represent a discretionary sale by the reporting person.

Represents the award of Restricted Stock Units (RSUs) under the Casella Waste Systems, Inc. Amended and Restated 2016 Incentive Plan. Each RSU represents a contingent right to receive one share of Casella's Class A Common Stock. RSUs vest in three equal annual installments beginning on March 12, 2027.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of RSUs previously granted to the reporting person. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 2, 2023 and does not represent a discretionary sale by the reporting person.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of RSUs previously granted to the reporting person. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 2, 2023 and does not represent a discretionary sale by the reporting person.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of PSUs previously granted to the reporting person on March 10, 2023. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 2, 2023 and does not represent a discretionary sale by the reporting person.

Represents the weighted average sales price for shares sold in multiple transactions, ranging from $93.69 to $93.86. Upon request of the staff of the Securities and Exchange Commission, the issuer or a security holder of the issuer, the reporting person will provide full information regarding the number of shares sold at each separate price.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of PSUs previously granted to the reporting person on March 10, 2023. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 2, 2023 and does not represent a discretionary sale by the reporting person.

Represents the weighted average sales price for shares sold in multiple transactions, ranging from $92.88 to $92.93. Upon request of the staff of the Securities and Exchange Commission, the issuer or a security holder of the issuer, the reporting person will provide full information regarding the number of shares sold at each separate price.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of PSUs previously granted to the reporting person on March 10, 2023. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 2, 2023 and does not represent a discretionary sale by the reporting person.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of PSUs previously granted to the reporting person on March 10, 2023. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 2, 2023 and does not represent a discretionary sale by the reporting person.

Represents the sale of shares of Class A Common Stock pursuant to a "sell-to-cover" transaction in order to satisfy tax withholding obligations in connection with the vesting of PSUs previously granted to the reporting person on March 10, 2023. This sale was effected pursuant to an automatic sell-to-cover instruction adopted by the reporting person on August 22, 2023 and does not represent a discretionary sale by the reporting person.

Represents the weighted average sales price for shares sold in multiple transactions, ranging from $93.00 to $93.68. Upon request of the staff of the Securities and Exchange Commission, the issuer or a security holder of the issuer, the reporting person will provide full information regarding the number of shares sold at each separate price.

Represents shares of Class A Common Stock acquired by the reporting person upon the vesting of performance-based stock units (PSUs) granted to the reporting person on March 10, 2023, as a result of the level of achievement by Casella Waste Systems, Inc. of certain performance objectives during the period running from January 1, 2025 through December 31, 2025, and a multiplier based on relative total shareholder return for the period running from January 1, 2023 to December 31, 2025, as certified by the issuer's compensation and human capital committee on February 26, 2026.

Represents shares of Class A Common Stock acquired by the reporting person upon the vesting of performance-based stock units (PSUs) granted to the reporting person on March 10, 2023, as a result of the level of achievement by Casella Waste Systems, Inc. of certain performance objectives during the period running from January 1, 2025 through December 31, 2025, and a multiplier based on relative total shareholder return for the period running from January 1, 2023 to December 31, 2025, as certified by the issuer's compensation and human capital committee on February 26, 2026.

Represents shares of Class A Common Stock acquired by the reporting person upon the vesting of performance-based stock units (PSUs) granted to the reporting person on March 10, 2023, as a result of the level of achievement by Casella Waste Systems, Inc. of certain performance objectives during the period running from January 1, 2025 through December 31, 2025, and a multiplier based on relative total shareholder return for the period running from January 1, 2023 to December 31, 2025, as certified by the issuer's compensation and human capital committee on February 26, 2026.

Represents shares of Class A Common Stock acquired by the reporting person upon the vesting of performance-based stock units (PSUs) granted to the reporting person on March 10, 2023, as a result of the level of achievement by Casella Waste Systems, Inc. of certain performance objectives during the period running from January 1, 2025 through December 31, 2025, and a multiplier based on relative total shareholder return for the period running from January 1, 2023 to December 31, 2025, as certified by the issuer's compensation and human capital committee on February 26, 2026.

Represents shares of Class A Common Stock acquired by the reporting person upon the vesting of performance-based stock units (PSUs) granted to the reporting person on March 10, 2023, as a result of the level of achievement by Casella Waste Systems, Inc. of certain performance objectives during the period running from January 1, 2025 through December 31, 2025, and a multiplier based on relative total shareholder return for the period running from January 1, 2023 to December 31, 2025, as certified by the issuer's compensation and human capital committee on February 26, 2026.

Represents the weighted average sales price for shares sold in multiple transactions, ranging from $99.66 to $100.40. Upon request of the staff of the Securities and Exchange Commission, the issuer or a security holder of the issuer, the reporting person will provide full information regarding the number of shares sold at each separate price.

Represents a gift of shares to the Goldman Sachs Philanthropy Fund.

Represents a gift of shares to the Ned and Elizabeth Coletta Fund, a Goldman Sachs Philanthropy Fund.