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March 14 (Reuters) - Mortgage insurer Radian Group said (RDN.N: Quote, Profile, Research) fourth-quarter loss was wider than reported earlier due to a fair value adjustment to certain non-corporate CDO transactions in the financial guaranty business.

The company, which sells policies to cover partial payment of mortgages in the event of a default, reported a net loss of $721 million, or $9.03 a share, compared with the net loss of $618 million, or $7.74 per share, reported on Feb. 15.

The company had posted a profit of $158.4 million, or $1.96 a share, in the year-ago period.

On March 3, Radian had said in a filing with the U.S. Securities and Exchange Commission that it was late with its 10-K report because it did not yet have fair value estimates for collateralized debt obligations, or CDOs, that it had insured.

In a regulatory filing on Friday, the company said the additional fair value loss has no impact on Radian Asset's claim paying resources for regulatory purposes or rating agency purposes.

Like many insurers, Philadelphia-based Radian has been battered as borrowers missed more payments and investors stopped buying a wide variety of debt perceived to carry too much credit risk.

Radian stock, which had lost about 50 percent of its value in the last three months, closed down about 7 percent at $5.15 on the New York Stock Exchange Friday. (Reporting by Supantha Mukherjee in Bangalore; Editing by Gopakumar Warrier)