X0303 4 2010-02-26 0 0001163348 ALLIED WORLD ASSURANCE CO HOLDINGS LTD AWH 0001368443 Carmilani Scott A ALLIED WORLD ASSURANCE CO HOLDINGS, LTD 27 RICHMOND ROAD PEMBROKE D0 HM 08 BERMUDA 1 1 0 0 President, CEO and Chrmn of Bd Common Shares 2010-02-26 4 M 0 2500 0.00 A 213659 D Common Shares 2010-02-26 4 D 0 1250 46.1354 D 212409 D Common Shares 2010-03-02 4 S 0 2508 46.39 D 209901 D Restricted Stock Units 2010-02-26 4 M 0 2500 D 2010-02-26 2013-02-26 Common Shares 1250 20500 D On February 26, 2009, the reporting person was granted 10,000 Restricted Stock Units for no monetary consideration. The Restricted Stock Units convert into (i) 5,000 of the Company's Common Shares and (ii) cash equal to the market value of 5,000 Common Shares (measured at the date of vesting) upon the 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, 2010. The sale of Common Shares reported in this Form 4 were for tax purposes and were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on February 24, 2009. The Restricted Stock Units vest in four equal annual installments with the first installment vesting on February 26, 2010. /s/ Wesley D. Dupont, by Power of Attorney 2010-03-02