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 * LOMBARDOZZI MICHAEL E   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) Exec. VP, Gen. Coun.and CAO (Last) (First) (Middle) THE BELVEDERE BUILDING, 69 PITTS BAY ROAD, 2ND FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 02/21/2011 (Street) PEMBROKE, D0 HM O8 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   7,280 A $ 0 167,060 D   Common Shares 02/21/2011   M   3,446 A $ 0 170,506 D   Common Shares 02/21/2011   A   16,443 (1) A $ 0 186,949 D

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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

Share units

(2)

02/21/2011

M

7,280

(3)

(3)

Common Shares (3)

7,280

$ 0

0

D

Share units

(2)

02/21/2011

M

3,446

(4)

(4)

Common Shares (4)

3,446

$ 0

3,446

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
LOMBARDOZZI MICHAEL E THE BELVEDERE BUILDING 69 PITTS BAY ROAD, 2ND FLOOR PEMBROKE, D0 HM O8			Exec. VP, Gen. Coun.and CAO

Signatures

/s/ Michael E. Lombardozzi		02/22/2011
**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)	These share units represent the payment of an award granted on February 21, 2008 under the Amended and Restated Executive Incentive Plan of Platinum Underwriters Holdings, Ltd. (the "Company") for the 2008-2010 performance cycle.
(2)	1-for-1
(3)	These share units were awarded on May 30, 2007 under the 2006 Share Incentive Plan of 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.
(4)	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.

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