Exhibit 99(b)
CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
We hereby consent to the incorporation by reference in the Registration Statement on Form S-8 (No. 333-68438) of White Mountains Insurance Group, Ltd. of our report dated June 27, 2006 relating to the financial statements of the OneBeacon Insurance Savings Plan, which appears in this Form 11-K.
/s/ PricewaterhouseCoopers LLP
Boston, Massachusetts
June 28, 2006