ABK Ambac Financial Grp. Common Stock

Ambac Financial Group, Inc. (NYSE: ABK) (Ambac) announced today that John W. Uhlein III, Ambac's Executive Vice President, will present at the William Blair Growth Stock Conference on June 22, 2005 at 1:00pm (CST) at the Four Seasons Hotel in Chicago. The presentation will be broadcast live from Ambac's website and a replay will be available immediately after the presentation for a total of 30 days. The link is: http://www.ambac.com 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, is a leading guarantor of municipal and structured finance obligations. It has earned triple-A ratings, the highest ratings available, from Moody's Investors Service, Inc., Standard & Poor's Ratings Services, Fitch, Inc. and Rating and Investment Information, Inc. Ambac Financial Group, Inc. common stock is listed on the New York Stock Exchange (ticker symbol ABK).