A.M. Best Withdraws Ratings of White Mountains Re Bermuda Ltd.

OLDWICK, N.J. -- A.M. Best Co. has withdrawn the financial strength rating (FSR) of A- (Excellent) and issuer credit rating (ICR) of "a-" and assigned a NR-5 (Not Formally Followed) to the FSR and a "nr" to the ICR of White Mountains Re Bermuda Ltd. (WMRe Bermuda), a subsidiary of White Mountains Re Group, Ltd. (White Mountains Re), which is a subsidiary of White Mountains Insurance Group, Ltd (White Mountains) (NYSE: WTM). All the above companies are domiciled in Hamilton, Bermuda.

In July 2009, White Mountains Re announced that it would reorganize its reinsurance operations whereby the in-force business and infrastructure of WMRe Bermuda would be transferred to its affiliate, Sirius International Insurance Corporation (WMRe Sirius) (Stockholm, Sweden), which established a branch office in Bermuda to maintain the group's presence in the Bermuda marketplace. WMRe Bermuda's loss exposures have been retroceded to WMRe Sirius and upon regulatory approval, WMRe Bermuda will be contributed to WMRe Sirius and in run off.

At this time, the remaining liabilities within WMRe Bermuda are not material to the overall organization; and consequently, the ratings have been withdrawn.

For Best's Credit Ratings, an overview of the rating process and rating methodologies, please visit www.ambest.com/ratings.

The principal methodologies used in determining these ratings, including any additional methodologies and factors that may have been considered, can be found at www.ambest.com/ratings/methodology.

Founded in 1899, A.M. Best Company is a global full-service credit rating organization dedicated to serving the financial and health care service industries, including insurance companies, banks, hospitals and health care system providers. For more information, visit www.ambest.com.