Ameresco, Inc. — Director's Dealing 2011

May 19, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Ameresco, Inc. (AMRC)
CIK: 0001488139
Period of Report: 2011-05-18

Reporting Person: Derrington Keith A (Executive Vice President)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-05-18	Class A Common Stock	M	5600	$2.75	Acquired	5600	Direct
2011-05-18	Class A Common Stock	S	5600	$15.00	Disposed	0	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2011-05-16	Stock Option (right to purchase)	$2.75	M	5600	Disposed	2014-06-25	Class A Common Stock (5600)	Direct

Footnotes

F1: The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 8, 2011.

F2: Of the shares subject to the option, 20% vested on June 25, 2005, and the remainder vested in 16 equal quarterly installments thereafter.