X0306 4 2013-02-26 0 0001163348 Allied World Assurance Co Holdings, AG AWH 0001456268 Gauthier John J ALLIED WORLD ASSURANCE CO. HOLDINGS, AG LINDENSTRASSE 8 BAAR/ZUG V8 CH-6340 SWITZERLAND 0 1 0 0 EVP & CIO, AWAC ServCo. Common Shares 2013-02-26 4 M 0 750 0.00 A 16755 D Common Shares 2013-02-26 4 D 0 375 87.6999 D 16380 D Common Shares 2013-02-26 4 F 0 201 88.18 D 16179 D Restricted Stock Units 2013-02-26 4 M 0 750 D Common Shares 750 5966 D On February 26, 2009, the reporting person was granted 3,000 Restricted Stock Units for no monetary consideration. The Restricted Stock Units convert into (i) 1,500 of the Company's Common Shares and (ii) cash equal to the market value of 1,500 Common Shares (measured at the date of vesting) of such Restricted Stock Units. 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 26, 2013. Exclusively represents shares withheld by the Company with respect to the payment of withholding tax liability incurred upon the vesting of Restricted Stock Units. The Restricted Stock Units vested in four equal annual installments with the first installment vesting on February 26, 2010. /s/ Wayne H. Datz, by Power of Attorney 2013-02-28