NEW YORK (Reuters) - XL Capital Ltd (XL.N: Quote, Profile, Research), a large Bermuda-based reinsurer, on Tuesday reported a $1.06 billion fourth-quarter loss, largely stemming from write-downs for its relationship with bond insurer Security Capital Assurance Ltd (SCA.N: Quote, Profile, Research).

The net loss was $6.01 per ordinary share, and compared with a profit of $471.1 million, or $2.62 per share, a year earlier. Excluding items, XL said it posted a fourth-quarter profit of $117.1 million, or 66 cents per share. That matched the average analyst forecast, according to Reuters Estimates.

Hamilton-based XL had announced plans on Jan. 23 to write off much of its $670 million investment in Security Capital, and to set aside $330 million for loss reserves related to the company. Net realized investment losses totaled $470.6 million, slightly below the $500 million XL had projected.

Bond insurers have suffered mounting losses tied to their guarantee of a wide variety of securities, including collateralized debt obligations, that have lost value as credit market conditions tightened.

(Reporting by Jonathan Stempel; Editing by Phil Berlowitz)