UNITED STATES

                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                    FORM 8-K/A

                                 CURRENT REPORT

                Pursuant to Section 13 or 15(d) of the Securities
                              Exchange Act of 1934

                                NOVEMBER 1, 2001
                Date of Report (Date of earliest event reported)


                      WHITE MOUNTAINS INSURANCE GROUP, LTD.

             (Exact name of registrant as specified in its charter)



                                                  
            BERMUDA                       1-8993              94-2708455
(State or other jurisdiction of        (Commission         (I.R.S. Employer
 incorporation or organization)        file number)       Identification No.)



               80 SOUTH MAIN STREET, HANOVER, NEW HAMPSHIRE 03755
                    (Address of principal executive offices)


                                 (603) 640-2202
              (Registrant's telephone number, including area code)




EXPLANATORY PARAGRAPH

White Mountains Insurance Group, Ltd. ("White Mountains" or the "Registrant")
is filing this Form 8-K/A to amend its Form 8-K/A dated November 1, 2001
(filed July 15, 2002) to reflect changes to the historical financial
statements of CGU Corporation and its subsidiaries ("OneBeacon") for the five
months ended May 31, 2001, a period which was prior to the Registrant's
acquisition of OneBeacon. These changes have no impact on the Registrant's
financial statements or tangible book value per share in any period. More
information on these changes is available on the Registrant's Form 8-K/A
dated June 1, 2001 (filed March 27, 2003).





ITEM 2. DISPOSITION OF ASSETS (OR BUSINESS)

White Mountains' wholly owned subsidiary, OneBeacon, previously announced
that it has executed a definitive agreement with Liberty Mutual Insurance
Group ("Liberty Mutual"). The agreement calls for Liberty Mutual, beginning
November 1, 2001 (the "Effective Date"), to assume new and renewal commercial
and personal lines business produced by OneBeacon agents in 42 states and the
District of Columbia. Additionally, OneBeacon will reinsure 67% of the
renewal premiums written and the net liability for loss and loss adjustment
expense of all renewal policies subject to the agreement during the first
twelve months after the Effective Date of the transaction and 33% of such net
premiums written and net liability for loss and loss adjustment expenses
during the following twelve months.

The press release issued by OneBeacon dated September 5, 2001 and a summary of
significant terms of the agreement in principle between OneBeacon and Liberty
Mutual were previously filed as Exhibits 99 (a) and 99 (b), respectively, to the
Form 8-K dated September 5, 2001 (filed September 7, 2001). The press release
issued by OneBeacon dated October 30, 2001 was previously filed as Exhibit 99
(c) to the Form 8-K amendment dated September 5, 2001 (filed October 31, 2001).

Also previously filed as Exhibits 99(d), 99(e), 99(f), 99(g) and 99(h) to Form
8-K dated September 5, 2001 (filed November 6, 2001) were the Master Agreement
by and among the Registrant, OneBeacon and Liberty Mutual, a Glossary of Terms
to the Master Agreement, the Renewal Rights Agreement by and among OneBeacon and
Liberty Mutual, the Peerless Post-Closing Indemnity Reinsurance Agreement by and
between OneBeacon and Peerless Insurance Company and the Rewritten Indemnity
Reinsurance Agreement by and between Peerless Insurance Company and OneBeacon,
respectively. The unaudited pro forma condensed combined income statements of
the Registrant for the year ended December 31, 2000 and the nine month period
ended September 30, 2001 were previously filed as Exhibit 99(i) to Form 8-K
dated November 1, 2001 (filed January 14, 2002).

The unaudited pro forma condensed combined income statement of the Registrant
for the year ended December 31, 2001 is enclosed herein as Exhibit 99(j), which
is incorporated by reference in its entirety.

ITEM 7. FINANCIAL STATEMENTS AND EXHIBITS.

    (b) PRO FORMA FINANCIAL INFORMATION.

The unaudited pro forma condensed combined income statement of the Registrant
for the year ended December 31, 2001, and the notes thereto, are enclosed herein
as Exhibit 99(j).


    (c) Exhibits.  The following exhibits are filed herewith:



EXHIBIT NO.               DESCRIPTION
            
   99(j)         The unaudited pro forma condensed combined income statement
                 of the Registrant for the year ended December 31, 2001 and the
                 notes thereto.






                                   SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.

                      WHITE MOUNTAINS INSURANCE GROUP, LTD.



DATED: MARCH 27, 2003           BY:  /s/  J. BRIAN PALMER
                                     ------------------------------------------
                                     CHIEF ACCOUNTING OFFICER