SEC FORM 4

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

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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^*

WHITE MOUNTAINS INSURANCE GROUP LTD

(Last)

(First)

(Middle)

80 SOUTH MAIN STREET

(Street)

HANOVER

03755

(City)

(State)

(Zip)

2. Issuer Name and Ticker or Trading Symbol
MONTPELIER RE HOLDINGS LTD [ MRH ]

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)
03/08/2005

4. If Amendment, Date of 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

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Shares	03/08/2005		J⁽¹⁾		3,063	A	$41.78	9,189	I	By Folksamerica Reinsurance Company⁽²⁾
Common Shares								3,600,000	I	By OneBeacon Insurance Company⁽²⁾
Common Shares								900,000	I	By OneBeacon Insurance Group LLC⁽²⁾
Common Shares								1,800,000	I	By Pennsylvania General Insurance Company⁽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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Warrant Shares	$16.67⁽³⁾							⁽⁴⁾	01/03/2012	Common Shares	7,172,357.5		7,172,357.5	I	By wholly-owned subsidiaries of White Mountains Insurance Group, Ltd. See Footnote 5.⁽⁵⁾

Explanation of Responses:

1. Pro rata distribution from Century Capital Partners LP, of which Folksamerica Reinsurance Company, an indirect wholly-owned subsidiary of White Mountains Insurance Group, Ltd., is a limited partner.

2. Folksamerica Reinsurance Company, OneBeacon Insurance Company, The Camden Fire Insurance Association, and Pennsylvania General Insurance Company are indirect wholly-owned subsidiaries of White Mountains Insurance Group, Ltd.

3. Warrants Shares are exercisable for Common Shares on a 1 for 1 basis at an exercise price of $16.67 per Warrant Share.

4. Currently exercisable.

5. Warrant Shares are held by Folksamerica Reinsurance Company, White Mountains Holdings Bermuda Ltd., Sirius International Insurance Corporation and White Mountains Financial Services Ltd., each an indirect wholly-owned subsidiary of White Mountains Insurance Group, Ltd.

Remarks:

	Dennis Beaulieu, Corporate Secretary, White Mountains Insurance Group, Ltd.	03/08/2005
	Dennis Beaulieu, by Power of Attorney on behalf of Folksamerica Reinsurance Company	03/08/2005
	Dennis Beaulieu, by Power of Attorney on behalf of OneBeacon Insurance Group, LLC, OneBeacon Insurance Company, and Pennsylvania General Insurance Company	03/08/2005
	Dennis Beaulieu, by Power of Attorney on behalf of White Mountains Holdings Bermuda Ltd.	03/08/2005
	Dennis Beaulieu, by Power of Attorney on behalf of Sirius International Insurance Corporation	03/08/2005
	Dennis Beaulieu, on behalf of White Mountains Financial Services Ltd.	03/08/2005
	** 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).
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