CASELLA WASTE SYSTEMS INC

Director and Officer Trading Arrangements

A portion of the compensation of our directors and officers (as defined in Rule 16a-1(f) under the Securities Exchange Act of 1934, as amended (“Exchange Act”)) is in the form of equity awards, including restricted stock units (“RSU(s)”) and performance stock units (“PSU(s)”), and, from time to time, directors and officers engage in open-market transactions with respect to the securities acquired pursuant to such equity awards or other securities of ours, including to satisfy tax withholding obligations when equity awards vest or are exercised, and for diversification or other personal reasons.

Transactions in our securities by directors and officers are required to be made in accordance with our insider trading policy, which requires that the transactions be in accordance with applicable U.S. federal securities laws that prohibit trading while in possession of material nonpublic information. Rule 10b5-1 under the Exchange Act provides an affirmative defense that enables directors and officers to prearrange transactions in our securities in a manner that avoids concerns about initiating transactions while in possession of material nonpublic information.

The following table describes, for the fourth quarter of fiscal year 2023, each trading arrangement for the sale or purchase of our securities adopted or terminated by our directors and officers that is either (1) a contract, instruction or written plan intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) (a “Rule 10b5-1 trading arrangement”) or (2) a “non-Rule 10b5-1 trading arrangement” (as defined in Item 408(c) of Regulation S-K):

(1)The number of shares subject to covered RSUs or PSUs that will be sold to satisfy applicable tax withholding obligations upon vesting is unknown as the number will vary based on the extent to which vesting conditions are satisfied, the market price of our common stock at the time of settlement and the potential future grant of additional RSUs or PSUs subject to this arrangement. This trading arrangement, which applies to RSUs or PSUs whether vesting is based on the passage of time and/or the achievement of performance goals, provides for the automatic sale of shares that would otherwise be issuable on each settlement date of a covered RSU or PSU in an amount sufficient to satisfy the applicable withholding obligation, with the proceeds of the sale delivered to us in satisfaction of the applicable withholding obligation.

None of our directors or officers terminated a Rule 10b5-1 trading arrangement oradopted orterminated a non-Rule 10b5-1 trading arrangement (as defined in Item 408(c) of Regulation S-K) during the fourth quarter of fiscal year 2023.