AT Atlantic Power Corporation

Brower Piven, A Professional Corporation announces that a class action lawsuit has been commenced in the United States District Court for the District of Massachusetts on behalf of purchasers of Atlantic Power Corporation ("Atlantic Power" or the "Company") (NYSE:AT) common stock during the period between July 23, 2010 and March 4, 2013, inclusive (the "Class Period"), including purchasers in the Company's registered public follow-on stock offerings on October 13, 2010 at $13.35 per share, October 13, 2011 at $13.00 per share, and June 27, 2012 at $12.76 per share, and those who acquired shares pursuant to the Company's divided reinvestment plan commenced on August 8, 2012.

If you have suffered a net loss from investment in Atlantic Power Corporation common stock purchased on or after July 23, 2010, and held through March 4, 2013, you may obtain additional information about this lawsuit and your ability to become a lead plaintiff by contacting Brower Piven at www.browerpiven.com, by email at hoffman@browerpiven.com, by calling 410/415-6616, or at Brower Piven, A Professional Corporation, 1925 Old Valley Road, Stevenson, Maryland 21153. Attorneys at Brower Piven have combined experience litigating securities and class action cases of over 60 years.

No class has yet been certified in the above action. Members of the Class will be represented by the lead plaintiff and counsel chosen by the lead plaintiff. If you wish to choose counsel to represent you and the Class, you must apply to be appointed lead plaintiff no later than May 7, 2013 and be selected by the Court. The lead plaintiff will direct the litigation and participate in important decisions including whether to accept a settlement and how much of a settlement to accept for the Class in the action.  The lead plaintiff will be selected from among applicants claiming the largest loss from investment in the Company during the Class Period.

The complaint accuses the defendants of violations of the Securities Exchange Act of 1934 by virtue of the defendants' failure to disclose during the Class Period that the Company was using all of its cash to pay its 10% dividend while its losses from operations were mounting such that its dividend was unsustainable, particularly since defendants knew but did not disclose that many of the Company's project contracts were scheduled to expire over the course of 2013 without new contracts to take their place. According to the Complaint, following the Company's November 5, 2012 disclosure of its third-quarter 2012 financial results and a loss of $0.06 per share, the November 7, 2012 calculation by a stock analyst at RBC that Atlantic Power would need to make at least $750 million of accretive equity investments to maintain its 100% payout ratio on the outsized annual dividend in 2014, the January 31, 2013 disclosure that Atlantic Power intended to sell three of its Florida sites to Quantum Utility, the February 19, 2013 research report by RBC calculating that the Company would have to cut its dividend by 30% based on its fourth quarter 2012 financial results for the interim quarter and fiscal year ending December 31, 2012, the Company's February 28, 2013 disclosure that its fourth quarter loss from continuing operations was $0.20 per share and that the Company was cutting its annual dividend by 65%, and the March 4, 2013 research report by RBC that warned that investors could not assume the 65% divided cut would ensure the long-term sustainability of Atlantic Power's dividend and that the Company would have to sell additional debt and/or common equity in 2014 to fund $235 million of debt securities, the value of Atlantic Power shares declined significantly.

If you choose to retain counsel, you may retain Brower Piven without financial obligation or cost to you, or you may retain other counsel of your choice. You need take no action at this time to be a member of the class.

CONTACT: Charles J. Piven
         Brower Piven, A Professional Corporation
         Stevenson, Maryland
         410/415-6616
         hoffman@browerpiven.com