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 *
Grossack Marshall J
   2. Issuer Name and Ticker or Trading Symbol
Allied World Assurance Co Holdings, AG [AWH] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
EVP, Chief Actuary
(Last)
(First)
(Middle)
ALLIED WORLD ASSURANCE CO. HOLDINGS, AG, LINDENSTRASSE 8		 3. Date of Earliest Transaction (Month/Day/Year)
02/22/2013
(Street)

BAAR/ZUG, V8 CH-6340		 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 02/22/2013   M   487 A $ 0 (1) 64,354 D  
Common Shares 02/22/2013   M   298 A $ 0 (2) 64,652 D  
Common Shares 02/22/2013   M   825 A $ 0 (3) 65,477 D  
Common Shares 02/22/2013   D   869 D $ 87.3758 (4) 64,608 D  
Common Shares 02/22/2013   F   378 (5) D $ 88.03 64,230 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
Restricted Stock Units (1) 02/22/2013   M     487 (1)   (6)   (6) Common Shares 487 (1) (1) 7,576 (7) D  
Restricted Stock Units (2) 02/22/2013   M     298 (2)   (8)   (8) Common Shares 298 (2) (2) 7,278 D  
Restricted Stock Units (3) 02/22/2013   M     825 (3)   (9)   (9) Common Shares 825 (3) (3) 6,453 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Grossack Marshall J
ALLIED WORLD ASSURANCE CO. HOLDINGS, AG
LINDENSTRASSE 8
BAAR/ZUG, V8 CH-6340		       EVP, Chief Actuary  

Signatures

 /s/ Wayne H. Datz, by Power of Attorney   02/26/2013
**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 February 22, 2012, the reporting person was granted 1,950 Restricted Stock Units for no monetary consideration. The Restricted Stock Units convert into (i) 390 of the Company's Common Shares and (ii) cash equal to the market value of 1,560 Common Shares (measured at the date of vesting) upon the vesting of such Restricted Stock Units.
(2) On February 22, 2011, the reporting person was granted 1,190 Restricted Stock Units for no monetary consideration. The Restricted Stock Units convert into (i) 595 of the Company's Common Shares and (ii) cash equal to the market value of 595 Common Shares (measured at the date of vesting) upon the vesting of such Restricted Stock Units.
(3) On February 22, 2010, the reporting person was granted 3,300 Restricted Stock Units for no monetary consideration. The Restricted Stock Units convert into (i) 1,980 of the Company's Common Shares and (ii) cash equal to the market value of 1,320 Common Shares (measured at the date of vesting) upon the vesting of such Restricted Stock Units.
(4) The fair market value of the cash portion was determined using the daily volume-weighted average sales price of the Company's Common Shares for the five consecutive trading days up to and including February 22, 2013.
(5) Exclusively represents shares withheld by the Company with respect to the payment of withholding tax liability incurred upon the vesting of Restricted Stock Units.
(6) The Restricted Stock Units vest in four equal installments with the first installment vesting on February 22, 2013.
(7) Represents all Restricted Stock Units held by the reporting person that vest in whole or in part in cash.
(8) The Restricted Stock Units vest in four equal installments with the first installment vesting on February 22, 2012.
(9) The Restricted Stock Units vest in four equal installments with the first installment vesting on February 22, 2011.

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