Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
BARRETTE RAYMOND JOSEPH RENE
   2. Issuer Name and Ticker or Trading Symbol
WHITE MOUNTAINS INSURANCE GROUP LTD [WTM] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
President & CEO
(Last)
(First)
(Middle)
C/O WHITE MOUNTAINS INSURANCE GROUP, 80 SOUTH MAIN STREET		 3. Date of Earliest Transaction (Month/Day/Year)
12/20/2004
(Street)

HANOVER, NH 03755		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Shares 11/19/2004   G V 1,500 D (1) 18,006 D  
Common Shares 12/20/2004   F   97 (2) D $ 629.75 (3) 17,909 D  
Common Shares 12/20/2004   M   435 A $ 140.57 18,344 D  
Common Shares               3,700 I By IRA
Common Shares               563 (4) I By 401(k)

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Common Share Options $ 140.57 12/20/2004 12/20/2004 M     435   (5) 02/28/2010 Common Shares 435 (6) 7,230 D  
Phantom Shares (Deferred Compensation) (7)               (8)   (8) Common Shares (7)   7,668 D  
Phantom Shares (Deferred Compensation (7)               (9)   (9) Common Shares (7)   40,903 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
BARRETTE RAYMOND JOSEPH RENE
C/O WHITE MOUNTAINS INSURANCE GROUP
80 SOUTH MAIN STREET
HANOVER, NH 03755		   X     President & CEO  

Signatures

 Dennis Beaulieu, by Power of Attorney   12/21/2004
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Value of WTM Common Shares gifted based on the closing market price of WTM's Common Shares.
(2) Common Shares delivered to WTM as payment for the December 20, 2004 exercise of options to purchase 435 Common Shares of WTM pursuant to that certain Incentive Stock Option Agreement between WTM and the Reporting Person dated January 28, 2000.
(3) Based on WTM's closing market price per Common Share on December 20, 2004.
(4) Since March 14, 2004, the date of Reporting Person's last filing, Reporting Person acquired 49 shares of WTM's Common Shares under the Folksamerica 401(k) Plan. WTM Common Shares are purchased at fair market value on the date of purchase. The information in this report is based on a plan statement dated as of November 30,2004.
(5) Reporting Person was originally granted 9,000 options to purchase Common Shares on February 28, 2000. 900 options become exercisable annually over a ten-year period. 335 options were exercised on December 27, 2001 at an exercise price of $118.15 and 1,000 options were exercised on December 30, 2002 at an exercise price of $125.30.
(6) On February 28, 2000, the Reporting Person was granted options to purchase WTM Common Shares on a 1 for 1 basis at an initial exercise price of $106.19. The exercise price increases by 6% annually on a cumulative basis.
(7) Phantom Shares are convertible into Common Shares on a 1 for 1 basis.
(8) Payment of deferred compensation balances is due in cash based on a predetermined Payment Schedule entered into in October 1999 by the Reporting Person.
(9) 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.

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