Sec Form 4 Filing - HANCOCK PAUL J @ BERKLEY W R CORP - 2010-03-02

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 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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1. Name and Address of Reporting Person HANCOCK PAUL J 2. Issuer Name and Ticker or Trading Symbol BERKLEY W R CORP [ WRB] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) SVP - Chief Corporate Actuary (Last) (First) (Middle) W. R. BERKLEY CORPORATION, 475 STEAMBOAT ROAD 3. Date of Earliest Transaction (MM/DD/YY) 03/02/2010 (Street) GREENWICH, CT06830 4. If Amendment, Date Original Filed (MM/DD/YY) 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 (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 03/02/2010 A 12,000 ( 1 ) A $ 0 87,875 D Common Stock 03/02/2010 M 15,187 A $ 3.06 103,062 ( 2 ) D

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 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 Employee Stock Option (Right to Buy) $ 3.06 ( 3 ) 03/02/2010 M 15,187 ( 3 ) ( 4 ) 03/16/2010 Common Stock 15,187 ( 3 ) $ 0 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other HANCOCK PAUL J W. R. BERKLEY CORPORATION 475 STEAMBOAT ROAD GREENWICH, CT06830 SVP - Chief Corporate Actuary Signatures Paul J. Hancock 03/03/2010 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents restricted stock units granted under the W. R. Berkley Corporation 2003 Stock Incentive Plan that are scheduled to vest on March 2, 2015. ( 2 )Includes 66,375 restricted stock units, 30,375 of which have vested (the receipt of which have been deferred) and the balance of which are scheduled to vest as follows: 12,000 on December 5, 2010, 12,000 on December 17, 2012 and 12,000 on March 2, 2015. ( 3 )This stock option grant was originally reported as covering 6,000 shares with an exercise price of $15.50 per share and has been adjusted to reflect the 3-for-2 stock splits of July 2002, August 2003, April 2005 and April 2006. ( 4 )Stock option grant vested in four equal installments on March 16, 2003, March 16, 2004, March 16, 2005 and March 16, 2006.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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