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

OMB APPROVAL OMB Number: 3235-0287 Expires: January 31, 2005 Estimated average burden hours per response... 0.5

(Print or Type Responses)

1. Name and Address of Reporting Person * Decleir Allan Carl   2. Issuer Name and Ticker or Trading Symbol PLATINUM UNDERWRITERS HOLDINGS LTD [PTP] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) EVP & Chief Financial Officer (Last) (First) (Middle) THE BELVEDERE BUILDING, 69 PITTS BAY ROAD 3. Date of Earliest Transaction (Month/Day/Year) 02/21/2011 (Street) PEMBROKE, D0 HM 08 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 02/21/2011   M   601 A $ 0 5,649 D   Common Shares 02/21/2011   M   553 A $ 0 6,202 D   Common Shares 02/22/2011   M   678 A $ 0 6,880 D   Common Shares 02/23/2011   M   873 A $ 0 7,753 D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
	Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.		SEC 1474 (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 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
Share units	(1)	02/21/2011		M			601	(2)	(2)	Common Shares (2)	601	$ 0	0	D
Share units	(1)	02/21/2011		M			553	(3)	(3)	Common Shares (3)	553	$ 0	553	D
Share units	(1)	02/22/2011		M			678	(4)	(4)	Common Shares (4)	678	$ 0	2,033	D
Share units	(1)	02/23/2011		M			873	(5)	(5)	Common Shares (5)	873	$ 0	1,745	D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Decleir Allan Carl THE BELVEDERE BUILDING 69 PITTS BAY ROAD PEMBROKE, D0 HM 08			EVP & Chief Financial Officer

Signatures

/s/ Michael E. Lombardozzi, Attorney-in-Fact		02/23/2011
**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)	1-for-1
(2)	These share units were awarded on May 30, 2007 under the 2006 Share Incentive Plan of Platinum Underwriters Holdings, Ltd. (the "Company"). On February 21, 2011, the remaining 50% of these share units vested and the Company issued to the reporting person one Common Share for each vested share unit.
(3)	These share units were awarded on February 21, 2008 under the 2006 Share Incentive Plan. On February 21, 2011, 50% of these share units vested and the Company issued to the reporting person one Common Share for each vested share unit. On February 21, 2012, the Company will issue to the reporting person one Common Share for each of the remaining 50% of the share units awarded to the reporting person.
(4)	These share units were granted on February 22, 2010 under the 2006 Share Incentive Plan. On February 22, 2011, the first quarter of these share units vested and the Company issued to the reporting person one Common Share for each vested share unit. The remaining share units will vest ratably on the second, third and fourth anniversaries of the date of grant and on these vesting dates the Company will issue to the reporting person one Common Share for each vested share unit.
(5)	These share units were granted on February 23, 2009 under the 2006 Share Incentive Plan. On February 23, 2011, the second quarter of these share units vested and the Company issued to the reporting person one Common Share for each vested share unit. The remaining shares will vest ratably on the third and fourth anniversaries of the date of grant and on these vesting dates the Company will issue to the reporting person one Common Share for each vested share unit.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.