X0201 4 2004-03-24 0000776867 WHITE MOUNTAINS INSURANCE GROUP LTD WTM 0001181384 CAVOORES JOHN PAUL C/O WHITE MOUNTAINS INSURANCE GROUP, LTD 80 SOUTH MAIN STREET HANOVER NH 03755 0 1 0 0 Pres & CEO, OneBeacon Common Shares 1450 D Common Shares 10 I By 401(k) Common Shares 5 I By ESOP Phantom Shares (Deferred Compensation) 2004-03-24 2004-03-24 4 A 0 1 A Common Shares 1 141 D Since December 31, 2003, the Reporting Person acquired 5 shares of WTM's Common Shares under the OneBeacon Employee Stock Option Plan. WTM Common Shares are purchased at the fair market value on the date of purchase. The information contained in this report is based on a plan statement dated as of February 27, 2004. Phantom Shares are convertible into Common Shares on a 1 for 1 basis. On March 24, 2004, the Reporting Person's deferred compensation account was credited with a Phantom Share equal in value to the ordinary dividend paid on the underlying WTM Common Shares on the dividend date. The Phantom Shares are payable, at the election of the Company, in cash or in Common Shares following termination of the Reporting Person's employment with the Company or beginning at an earlier date selected by the Reporting Person. Dividends are automatically invested in Phantom Shares at the fair market price of the underlying WTM Common Shares on March 24, 2004, the date the dividends are deemed to be paid. Dennis Beaulieu 2004-03-26