Ambac Financial Group Inc, which was the second-largest U.S. bond insurer before suffering huge losses on risky mortgages, filed for Chapter 11 bankruptcy on Monday.
The company, which filed in Manhattan bankruptcy court, said it had liabilities of $1.68 billion. The company's shares plummeted in after-hours trading to 20 cents, down from 52 cents at their close on the New York Stock Exchange.