Radian Group Inc. (RDN) posted a net loss of $119.3 million, or 90 cents a share, in the second quarter as the mortgage insurer faced losses on the changing fair value of derivatives and financial instruments.

That compares to 2Q income of $137.1 million, or $1.03 a share, for the same period a year earlier.

At the same time, new mortgage insurance volumes tripled in the first half of the year, suggesting positive growth on the new business side. The company reported $8.3 billion in new primary insurance business in 2Q, up from $2.2 billion a year earlier. In just the first half, the company recorded $14.8 billion in newly written insurance, up from $4.9 billion in the first part of 2011.  

Most of the newly written insurance was tied to loans with FICO scores of 740 or above. In that category alone, the insurer noted $6.3 billion in new business in the second quarter.

FICO scores in the 680-to-739 range accounted for $1.8 billion in new contracts. Meanwhile, borrowers with FICO scores in the 620-to-679 range accounted for only $193 million in new primary insurance.

Like other mortgage insurers, Radian continues to battle fluctuations in its risk-to-capital ratio. The insurer's ratio hit 21-to-1 in June, up from 20.6-to-1 in March.