NEW YORK_Bond insurer Ambac Financial Group Inc. posted a $2.4 billion second-quarter loss Friday, as steep losses in residential mortgage-backed securities helped reverse its year-earlier profit.

For the three months ending June 30, the company lost $8.33 per share, compared with a profit of $823.1 million, or $2.80 per share, in the year-earlier period.

Analysts polled by Thomson Reuters forecast a loss of $1.04 per share.

Shares of Ambac slid 31 cents, or 22 percent, to $1.07, in afternoon trading.

The New York-based company said it recorded $1.23 billion in losses from its financial guarantee segment, driven primarily by residential mortgage-related securities.

Its Ambac Assurance Corp. recorded a loss of $675.4 million and its investment agreement business recorded a loss of $186.7 million as a result of selling of certain investment portfolio securities.

Net premiums earned for the quarter were $177.7 million, down 45 percent from $325.5 million a year ago.

"The quarter's financial results are obviously very disappointing, as continued poor performance of the mortgage-related portfolios and rising forward interest rates have escalated projections of future claims," Ambac's President and CEO David Wallis said in a statement.

He noted that the company is working to manage its risk. In July, the company reduced a significant portion of its exposure under a collaterized debt obligation of asset-backed securities transaction via settlement.