The Ambac Financial Group, Inc., generally known as Ambac, (NYSE: ABK) is an American holing company whose subsidiaries provide financial guarantee products, such as bond insurance and other financial services to clients in both the public and private sectors around the world. Ambac is regulated by the insurance commission of Wisconsin. Through its financial services subsidiaries, the company provides investment agreements, interest rate swaps, investment advisory and cash management services, primarily to states, municipalities and their authorities.