UNITED STATES

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                  -------------

                                    FORM 8-K

                                 CURRENT REPORT

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


                                OCTOBER 31, 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) 643-1567
              (Registrant's telephone number, including area code)





ITEM 7.   FINANCIAL STATEMENTS AND EXHIBITS.

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

   EXHIBIT NO.       DESCRIPTION

   99 (a) Letter to shareholders from White Mountains' Chairman, John J. Byrne.

ITEM 9.   REGULATION FD DISCLOSURE.

White Mountains Insurance Group, Ltd.'s (the "Registrant") Chairman, John J.
Byrne, issued a letter dated October 31, 2001 providing recent developments
concerning White Mountains' subsidiaries, OneBeacon Corporation and Folksamerica
Reinsurance Company. The Chairman's letter to shareholders dated October 31,
2001 is furnished herewith as Exhibit 99(a) and is incorporated by reference in
its entirety.







                                   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: November 1, 2001                 BY: /s/ J. Brian Palmer
                                            ----------------------------
                                            J. Brian Palmer
                                            Chief Accounting Officer