Assured Guaranty post 1Q loss on increased credit losses

Meanwhile, Assured continued to expand its market share, taking advantage of major stumbles by its competitors in this once-conservative industry, which used to insure only municipal bonds.

The firm's new business reached $276.6 million in the period, more than double the year-ago result. Premium income more than tripled.

Competitors such as MBIA Inc. and Ambac Financial got caught wrong-footed when they started insuring mortgage debt and riskier, more complex investments. The risk that those types of bonds will result in higher claims cost them top-notch credit ratings that are essential in the business.

Assured has been "gaining massive market share," Lane said, because it is one of only two bond insurers with 'AAA' ratings from all three major agencies.

Last month, billionaire investor Wilbur Ross bought shares worth $250 million in the company and promised to invest another $750 million more to finance its anticipated growth.

Ross, who was appointed to Assured Guaranty's board, at the time said he was "greatly impressed" by the "dramatic gains in market share" the company had earned.

In electronic aftermarket trading, Assured shares shed $3.34, or 13 percent, to $22.05 after closing Thursday at $25.39. In the past year, the stock has ranged from $13.34 to $31.