Ambac Announces Resignation of Sean Leonard, Senior Vice President and Chief Financial Officer.

NEW YORK -- Ambac Financial Group, Inc. (NYSE: ABK) (Ambac) announced that Sean Leonard has resigned as Senior Vice President and Chief Financial Officer of Ambac to pursue other interests. Mr. Leonard's resignation is effective today and, until such time as a replacement is named, his department heads will report directly to David Wallis, President and Chief Executive Officer.

Mr. Wallis commented, "Since joining Ambac in 2005, Sean has been a very valuable and hard working member of the executive team. Sean's experience, intelligence and dedication have had a strong and positive impact on the Company. We are fortunate to have had him as part of the executive team and he will be greatly missed."

About Ambac

Ambac Financial Group, Inc., headquartered in New York City, is a holding company whose affiliates provide financial guarantees and financial services to clients in both the public and private sectors around the world. Ambac's principal operating subsidiary, Ambac Assurance Corporation, a guarantor of public finance and structured finance obligations, has a Caa2 rating (developing outlook) from Moody's Investors Service, Inc. and a CC rating (credit watch positive) from Standard & Poor's Ratings Services. Ambac Financial Group, Inc. common stock is listed on the New York Stock Exchange (ticker symbol ABK).