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 * LEHMAN BROTHERS HOLDINGS INC   2. Issuer Name and Ticker or Trading Symbol Flagstone Reinsurance Holdings Ltd [FSR] 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) 745 SEVENTH AVENUE 3. Date of Earliest Transaction (Month/Day/Year) 07/27/2007 (Street) NEW YORK, NY 10019 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 Stock 07/27/2007   S   500 D $ 13.098 15,830,000 I See Footnote (1)

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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
LEHMAN BROTHERS HOLDINGS INC 745 SEVENTH AVENUE NEW YORK, NY 10019		X

Signatures

/s/ Barrett S. DiPaolo		08/01/2007
**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)	By indirect, wholly-owned subsidiaries of the Reporting Person: 5,117,509 shares held by Lehman Brothers Merchant Banking Partners III L.P.; 1,127,932 held by Lehman Brothers Merchant Banking Fund III L.P; 1,359,223 held by Lehman Brothers Merchant Banking Fund (B) III L.P.; 2,147,199 held by LB I Group Inc.; 172,182 held by Lehman Brothers Co-Investment Capital Partners L.P.; 122,082 held by Lehman Brothers Co-Investment Group L.P.; 4,705,737 held by Lehman Brothers Co-Investment Partners L.P.; 430,000 held by Lehman Brothers Fund of Funds XVIII-Co-Investment Holdings, L.P.; 248,137 held by Lehman Brothers Merchant Banking Capital Partners V L.P.; and 400,000 held by Lehman Crossroads Series XVII Master Holding Fund 66, L.P.
Remarks: See Exhibit 99.1 for Joint Filer Information.

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