Ameresco, Inc.

Stockholder Proposals

Stockholder proposals, including information about a proposed director candidate, submitted pursuant to Exchange Act Rule 14a-8 and intended to be presented at our 2027 annual meeting of stockholders must be received by our Secretary at the address noted below no later than December 25, 2026 to be eligible for inclusion in our proxy statement and form of proxy relating to that meeting. However, if the 2027 annual meeting of stockholders is called for a date that is not within 30 days before or after June 4, 2027, then we must receive your stockholder proposal or information about your proposed director candidate at the address noted below a reasonable time before we begin to print and mail our proxy materials for the 2027 annual meeting of stockholders.

If you wish to present a proposal at the 2027 annual meeting of stockholders, but do not wish to have the proposal considered for inclusion in our proxy statement and proxy card, you must give written notice at the address noted below. The required notice must be in writing and must otherwise meet the requirements set forth in our bylaws (including providing the information required by Rule 14a-19 under the Exchange Act). We must receive this required notice by March 6, 2027 (90 days fromthe anniversary of the 2026 annual meeting), but no sooner than February 4, 2027 (120 days fromthe anniversary of the 2026 annual meeting). However, if the date of the 2027 annual meeting of stockholders is held before May 5, 2027 or after August 3, 2027, we must receive the stockholder’s notice not earlier than the close of business on the 120th day before the 2027 annual meeting of stockholders and not later than the close of business on the later of (1)

the 90th day before the 2027 annual meeting of stockholders and (2) the 10th day following the day on which public announcement of the date of the 2027 annual meeting of stockholders is first made, whether by mail or public disclosure.

All stockholder proposals for our 2027 annual meeting of stockholders should be sent to the Secretary, Ameresco, Inc., 111 Speen Street, Suite 410, Framingham, Massachusetts 01701.

Other Stockholder Communications

Generally, stockholders who have questions or concerns should contact our Investor Relations department at (508) 598-3003 or via the form at https://www.ameresco.com/contact-us/. However, stockholders who wish to communicate directly with our board of directors, or any individual director, should direct questions in writing to the Secretary, Ameresco, Inc., 111 Speen Street, Suite 410, Framingham, Massachusetts 01701. See “Corporate Governance—Communicating with our Board of Directors” for more information about communicating with our board of directors.

Incorporation by Reference

Notwithstanding anything to the contrary set forth in any of our previous filings under the securities laws that might incorporate future filings, including this proxy statement, in whole or in part, the Compensation Committee Report, the contents of www.ameresco.com, including the charters of the committees of our board of directors, corporate governance guidelines, the Audit Committee Report and code of business conduct and ethics, included or referenced in this proxy statement shall not be incorporated by reference into any such filings.

Householding of Annual Meeting Materials

Some broker, bank or other agents may participate in thepractice of householding proxy statements and annual reports. This means that, unless you have instructed otherwise, only one copy ofthe Notice our proxy statement and annual report may have been sent to multiple stockholders in your household. If you want to receive separate copies of our proxy statement or annual report in the future, or if you are receiving multiple copies and would like to receive only one copy for your household, you should contact your broker, bank or other agent. Stockholders who currently receive multiple copies of the proxy statement at their address and would like to request “householding” of their communications should contact their broker, bank or other agent.

In addition, we will promptly deliver, upon written or oral request to Investor Relations, Ameresco, Inc., 111 Speen Street, Suite 410, Framingham, Massachusetts 01701, (508) 598-3003, a separate copy of the annual report and proxy statement to a stockholder at a shared address to which a single copy of the documents was delivered.