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 *
BYRNE MARK JAMES
   2. Issuer Name and Ticker or Trading Symbol
Flagstone Reinsurance Holdings, S.A. [FSR] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
48 PAR LA VILLE ROAD, SUITE 504		 3. Date of Earliest Transaction (Month/Day/Year)
05/25/2010
(Street)

HAMILTON, D0 HM11		 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 05/25/2010   S(1)   2,000,000 D $ 12 5,155,156 I By Limestone Business Limited (2)
Common Shares               2,849,719 I By Haverford (Bermuda) Ltd. (3)
Common Shares               50,000 I By Rebecca Byrne (4)

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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

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
BYRNE MARK JAMES
48 PAR LA VILLE ROAD
SUITE 504
HAMILTON, D0 HM11		   X   X    

Signatures

 /s/ Mark J. Byrne   05/27/2010
**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) On May 25, 2010, Limestone Business Limited ("Limestone") sold 2,000,000 common shares to the issuer for cash consideration of $12.00 per share in a private transaction.
(2) These common shares are held by Limestone, which is owned by a trust, established for the benefit of others, for which the reporting person is the settlor. The reporting person disclaims beneficial ownership of these shares.
(3) The reporting person is the Chairman and CEO of Haverford Bermuda Limited, and therefore has voting control over Haverford (Bermuda) Ltd. ("Haverford"). Approximately 92% of the equity interests of Haverford are held by Limestone, which is owned by a trust, established for the benefit of others, for which the reporting person is the settlor. 2,849,719 common shares represent the indirect proportionate interest of the reporting person in the 3,075,618 common shares of the issuer held by Haverford. The reporting person disclaims beneficial ownership of these shares.
(4) These common shares represent shares purchased in connection with the initial public offering of the issuer and are owned by Rebecca Byrne, the wife of the reporting person. The reporting person disclaims beneficial ownership of these shares.

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