X0304 4 2012-03-12 0 0001488139 Ameresco, Inc. AMRC 0001496421 Derrington Keith A C/O AMERESCO, INC. 111 SPEEN STREET , SUITE 410 FRAMINGHAM MA 01701 0 1 0 0 Executive Vice President Class A Common Stock 2012-03-12 4 M 0 15000 3.41 A 15000 D Class A Common Stock 2012-03-12 4 S 0 15000 13.519 D 0 D Stock Option (right to purchase) 3.41 2012-03-12 4 M 0 15000 0.00 D 2017-01-24 Class A Common Stock 15000 70000 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 8, 2011. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $13.31 to $13.68, inclusive. The reporting person undertakes to provide to Ameresco, Inc., any security holder of Ameresco, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (2) to this Form 4. Of the shares subject to the option, 20% vested on January 24, 2008 and the remainder vested in 16 equal quarterly installments thereafter. David J. Corrsin, Attorney-in-fact 2012-03-13