Press Release

Douglas Renfield-Miller, Senior Managing Director, to Present at William Blair Growth Stock Conference

NEW YORK, June 12, 2006 -- Ambac Financial Group, Inc. (NYSE:ABK) announced today that Douglas Renfield-Miller, Ambac's Senior Managing Director and Chairman of Ambac Assurance UK Limited, will present at the William Blair Growth Stock Conference on June 29, 2006 at 12:30pm (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.wsw.com/webcast/blair6/abk/

* * * * * * *

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, 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).