SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* BERKSHIRE HATHAWAY INC (Last) (First) (Middle) 1440 KIEWIT PLAZA (Street) OMAHA NE 68131 (City) (State) (Zip)	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) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 06/29/2004
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

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, $1.00 par value(1)	06/29/2004		C		1,724,200	A	$170.51	1,724,200	D(2)

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 Securities Underlying Derivative Security (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: 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
Warrant (right to buy)	$170.51	06/29/2004		C			1,724,200	06/29/2004	06/01/2008	Common Shares(1)	1,724,200	$175	0	D(2)

1. Name and Address of Reporting Person* BERKSHIRE HATHAWAY INC (Last) (First) (Middle) 1440 KIEWIT PLAZA (Street) OMAHA NE 68131 (City) (State) (Zip)

1. Name and Address of Reporting Person* BUFFETT WARREN E (Last) (First) (Middle) 1440 KIEWIT PLAZA (Street) OMAHA NE 68131 (City) (State) (Zip)

1. Name and Address of Reporting Person* GENERAL RE CORP (Last) (First) (Middle) BERKSHIRE HATHAWAY INC. 1440 KIEWIT PLAZA (Street) OMAHA NE 68131 (City) (State) (Zip)

Explanation of Responses:

1. These securities include (i) 544,285 common shares issuable upon the exercise of Series B Warrants pursuant to the approval of White Mountain's shareholders on August 23, 2001 and (ii) 9,915 common shares issuable upon the exercise of the Series A Warrants and Series B Warrants due to an issuance of convertible preference shares and common shares by White Mountains on October 24, 2002.

2. These securities are owned directly by General Reinsurance Corporation, which is a wholly-owned subsidiary of General Re Corporation, which is a wholly-owned subsidiary of Berkshire Hathaway Inc. General Re Corporation and Berkshire Hathaway Inc. are indirect beneficial owners of the reported securities.

	/s/ Marc D. Hamburg, Chief Financial Officer on behalf of Berkshire Hathaway Inc.	07/01/2004
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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Joint Filer Information                                     Exhibit 99

Name:  Warren E. Buffett

Address:  Berkshire Hathaway Inc.
	  1440 Kiewit Plaza
	  Omaha, Nebraska  68131

Designated Filer: Berkshire Hathaway Inc.

Issuer & Ticker
Symbol:  White Mountains Insurance Group,
Ltd.

Date of Event
	Requiring Statement: June 29, 2004


Signature:    /s/ Warren E. Buffett
                  Warren E. Buffett


Name:   General Re Corporation

Address:   Berkshire Hathaway Inc.
           1440 Kiewit Plaza
           Omaha, Nebraska  68131

Designated Filer: Berkshire Hathaway Inc.

Issuer & Ticker
Symbol: White Mountains Insurance Group,
Ltd.

Date of Event
	Requiring Statement: June 29, 2004


Signature:    /s/ William G. Gasdaska
		  Senior Vice President and CFO


Name:   General Reinsurance Corporation

Address:   Berkshire Hathaway Inc.
           1440 Kiewit Plaza
           Omaha, Nebraska  68131

Designated Filer: Berkshire Hathaway Inc.

Issuer & Ticker
Symbol: White Mountains Insurance Group,
Ltd.

Date of Event
	Requiring Statement: June 29, 2004


Signature:    /s/ Timothy T. McCaffrey
		  Secretary