FORM 5 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Form 3 Holdings Reported Form 4 Transactions Reported

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ANNUAL 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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1. Name and Address of Reporting Person * Lone Tree Holdings Ltd 2. Issuer Name and Ticker or Trading Symbol OneBeacon Insurance Group, Ltd. [OB] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O WHITE MOUNTAINS INSURANCE GROUP LTD., 80 SOUTH MAIN ST. 3. Statement for Issuer's Fiscal Year Ended (Month/Day/Year) 12/31/2011 (Street) HANOVER, NH 03755 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Reporting (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 at end of Issuer's Fiscal Year (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Amount (A) or (D) Price Class B Common Shares     3         D   Class B Common Shares 03/15/2007   S4 645,262 D $ 25.85 64,327,289 (2) D   Class B Common Shares     3         I by Sirius International Holdings (NL) B.V. Class B Common Shares     3         I by Star Re Ltd.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

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SEC 2270 (9-02)

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 at End of Issuer's Fiscal Year (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Lone Tree Holdings Ltd C/O WHITE MOUNTAINS INSURANCE GROUP LTD. 80 SOUTH MAIN ST. HANOVER, NH 03755	Â	  X	Â	Â

Signatures

Jason R. Lichtenstein by Power of Attorney		02/02/2012
**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)	The Reporting Person is an indirect wholly-owned subsidiary of White Mountains Insurance Group, Ltd. ("WMIG"), a public company which also reports beneficial ownership of all the Class B Common Shares ("Class B Shares") referenced in this filing. The Reporting Person became the direct beneficial owner of 72,400,000 Class B Shares via a contribution from its direct parent on December 14, 2006 (the contributor was also an indirect wholly-owned subsidiary of WMIG). On March 15, 2007, 645,262 Class B Shares were sold by the Reporting Person to the Issuer's ESOP (as disclosed in this filing and in a Form 4 filed by WMIG on such date). The remaining 71,754,738 Class B Shares have been held directly by the Reporting Person, or by one or more of its wholly-owned subsidiaries, since that time.
(2)	Reflects reduction in Class B Shares reported as held directly as a result of transfers from the Reporting Person to its indirect wholly-owned subsidiary, Sirius International Holdings (NL) B.V. ("SIH") on August 15, 2008 and July 1, 2011. Class B Shares were transferred from SIH to Star Re Ltd. ("Star Re") on December 6, 2011.
(3)	Reflects Class B Shares transferred to SIH from the Reporting Person on August 15, 2008 and July 1, 2011, less 1,249,178 Class B Shares transferred by SIH to Star Re on December 6, 2011.
(4)	Reflects Class B Shares transferred from SIH to Star Re on December 6, 2011.

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