ABK Ambac Financial Grp. Common Stock

Ambac Financial Group, Inc. (NYSE:ABK) today announced that its Board of Directors declared a regular quarterly cash dividend of $0.18 per share of common stock. The dividend is payable on June 6, 2007 to stockholders of record on May 22, 2007. 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 leading guarantor of public finance and structured finance obligations, has earned triple-A ratings, the highest ratings available from Moody�s Investors Service, Inc., Standard & Poor�s Ratings Services and Fitch, Inc. Ambac Financial Group, Inc. common stock is listed on the New York Stock Exchange (ticker symbol ABK).