FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF 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 *   O'SHAUGHNESSY JAMES 2. Date of Event Requiring Statement (Month/Day/Year) 03/29/2007 3. Issuer Name and Ticker or Trading Symbol Flagstone Reinsurance Holdings Ltd [FSR] (Last) (First) (Middle) FLAGSTONE REINSURANCE HOLDINGS LIMITED, 23 CHURCH STREET 4. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Chief Financial Officer 5. If Amendment, Date Original Filed(Month/Day/Year) (Street) HAMILTON, D0, HM11 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 Beneficially Owned

1.Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.			SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Performance Share Units	12/31/2008(1)	03/31/2009(2)	Common Shares	40,000 (3)	$ 0 (4)	D	Â
Performance Share Units	12/31/2009(1)	03/31/2010(2)	Common Shares	35,000 (3)	$ 0 (4)	D	Â

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
O'SHAUGHNESSY JAMES FLAGSTONE REINSURANCE HOLDINGS LIMITED 23 CHURCH STREET HAMILTON, D0, HM11	Â	Â	  Chief Financial Officer	Â

Signatures

/s/ James O'Shaughnessy		03/29/2007
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(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)	These Performance Share Units ("PSUs") would vest, subject to the contingency described in note 4 below and the other terms and conditions of the issuer's PSU Plan, on the date shown.
(2)	Assumes the issuer will settle these PSUs within three months of the vesting date.
(3)	Represents the mid-point of the vesting range described in note 4 below for these PSUs.
(4)	Vesting of PSUs is contingent upon the issuer meeting certain fully diluted return-on-equity ("FDROE") goals. Upon vesting, the PSU holder shall be entitled to receive a number of common shares of the issuer (or the cash equivalent, at the election of the issuer) equal to the product of the number of PSUs granted multiplied by a factor based on the issuer's FDROE during the vesting period. The factor will range between zero and two, depending on the FDROE achieved during the vesting period.

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