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<SEC-DOCUMENT>0001047469-10-009685.txt : 20101112
<SEC-HEADER>0001047469-10-009685.hdr.sgml : 20101111
<ACCEPTANCE-DATETIME>20101112140338
ACCESSION NUMBER:		0001047469-10-009685
CONFORMED SUBMISSION TYPE:	13F-HR
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100930
FILED AS OF DATE:		20101112
DATE AS OF CHANGE:		20101112
EFFECTIVENESS DATE:		20101112

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			WHITE MOUNTAINS INSURANCE GROUP LTD
		CENTRAL INDEX KEY:			0000776867
		STANDARD INDUSTRIAL CLASSIFICATION:	FIRE, MARINE & CASUALTY INSURANCE [6331]
		IRS NUMBER:				942708455
		STATE OF INCORPORATION:			D0
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		13F-HR
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	028-01681
		FILM NUMBER:		101185374

	BUSINESS ADDRESS:	
		STREET 1:		80 SOUTH MAIN ST
		CITY:			HANOVER
		STATE:			NH
		ZIP:			03755
		BUSINESS PHONE:		603 640 2200

	MAIL ADDRESS:	
		STREET 1:		80 SOUTH MAIN STREET
		CITY:			HANOVER
		STATE:			NH
		ZIP:			03755

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	WHITE MOUNTAINS INSURANCE GROUP INC
		DATE OF NAME CHANGE:	19990603

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	FUND AMERICAN ENTERPRISES HOLDINGS INC
		DATE OF NAME CHANGE:	19920703

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	FUND AMERICAN COMPANIES INC
		DATE OF NAME CHANGE:	19920701
</SEC-HEADER>
<DOCUMENT>
<TYPE>13F-HR
<SEQUENCE>1
<FILENAME>a2201040z13f-hr.txt
<DESCRIPTION>13F-HR
<TEXT>
<Page>

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM 13F

                               FORM 13F COVER PAGE

       INFORMATION REQUIRED OF INSTITUTIONAL INVESTMENT MANAGERS PURSUANT
  TO SECTION 13(f) OF THE SECURITIES EXCHANGE ACT OF 1934 AND RULES THEREUNDER

Report for the Calendar Year or Quarter Ended: September 30, 2010.
                                               -----------------------

Check Here if Amendment / /; Amendment Number:
                                               ---------
   This Amendment (Check only one.):    / / is a restatement.
                                        / / adds new holdings entries.

Institutional Investment Manager Filing this Report:

  Name:                                   White Mountains Insurance Group, Ltd.
                                          -------------------------------------
  Address of Principal Executive Office:  80 South Main Street
                                          -------------------------------------
                                          Hanover, New Hampshire   03755-2053
                                          -------------------------------------
                                          U.S.A.
                                          -------------------------------------

Form 13F File Number: 028-01681
                          ---------------------

The institutional investment manager filing this report and the person by whom
it is signed hereby represent that the person signing the report is authorized
to submit it, that all information contained therein is true, correct and
complete, and that it is understood that all required items, statements,
schedules, lists, and tables, are considered integral parts of this form.

Person Signing this Report on Behalf of Reporting Manager:

Name:    J. Brian Palmer
         --------------------------------------------
Title:   Vice President and Chief Accounting Officer
         --------------------------------------------
Phone:   (603) 640-2200
         --------------------------------------------

Signature, Place, and Date of Signing:

    /s/   J. Brian Palmer        Boston, Massachusetts    November 12, 2010
- -----------------------------    ---------------------    -----------------
        [Signature]                  [City, State]              [Date]

Report Type (Check only one.):

/ / 13F HOLDINGS REPORT. (Check here if all holdings of this reporting
    manager are reported in this report.)

/ / 13F NOTICE. (Check here if no holdings reported are in this report,
    and all holdings are reported by other reporting manager(s).)

/X/ 13F COMBINATION REPORT. (Check here if a portion of the holdings for this
    reporting manager are reported in this report and a portion are reported by
    other reporting manager(s).)

List of Other Managers Reporting for this Manager:

No.      Form 13F File Number        Name

1.       028-12951                   OneBeacon Insurance Group, Ltd.
- --           -----------------       -------------------------------
2.       028-00470                   White Mountains Advisors LLC
- --           -----------------       -------------------------------

<Page>

                              FORM 13F SUMMARY PAGE

Report Summary:

Number of Other Included Managers:               0
                                        --------------------

Form 13F Information Table Entry Total:          1
                                        --------------------

Form 13F Information Table Value Total: $      412
                                        --------------------
                                            (thousands)

<Page>

                           FORM 13F INFORMATION TABLE

                      WHITE MOUNTAINS INSURANCE GROUP, LTD.

<Table>
<Caption>
    COLUMN 1     COLUMN 2     COLUMN 3  COLUMN 4      COLUMN 5     COLUMN 6  COLUMN 7     COLUMN 8
- -------------------------------------------------------------------------------------------------------
                                                                                      VOTING AUTHORITY
                                          VALUE  SHRS OR  SH/PUT/ INVESTMENT  OTHER   -----------------
NAME OF ISSUER TITLE OF CLASS   CUSIP   (x1,000) PRN AMT PRN CALL DISCRETION MANAGERS SOLE  SHARED NONE
- -------------------------------------------------------------------------------------------------------
<S>            <C>            <C>       <C>        <C>      <C>      <C>       <C>    <C>   <C>    <C>
SIEMENS AG     SPONSORED ADR  826197501 $    412   3,900    SH       SOLE      N/A    3,900
</Table>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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