A.M. Best, the insurance ratings agency, affirmed its A+ (Superior) rating of Lehman Re Ltd., the Bermuda-based reinsurance subsidiary of Lehaman Brothers, the investment bank.

The outlook for the rating is stable.

Best attributed the rating to Lehman Re's "substantial capitalization, limited insurance liabilities, advanced risk management capabilities and the operating and strategic benefits it receives as an integral part of Lehman Brothers investment bank."

The benefits include a guarantee of its financial obligations by Lehman Brothers.

But the ratings agency noted that the reinsurer's advantages were offset by a brief operating history of four years and "certain potential uncertainties asssociated with Lehman Brothers' innovative (strategies)."