X0306 4 2015-02-22 0 0001163348 Allied World Assurance Co Holdings, AG AWH 0001368328 Dupont Wesley D ALLIED WORLD ASSURANCE CO. HOLDINGS, AG GUBELSTRASSE 24, PARK TOWER, 15TH FLOOR ZUG V8 6300 SWITZERLAND 0 1 0 0 EVP & General Counsel Common Shares 2015-02-22 4 M 0 2631 0.00 A 202537 D Common Shares 2015-02-22 4 M 0 1290 0.00 A 203827 D Common Shares 2015-02-22 4 D 0 2751 40.4481 D 201076 D Common Shares 2015-02-22 4 F 0 588 40.54 D 200488 D Restricted Stock Units 2015-02-22 4 M 0 2631 D Common Shares 2631 20316 D Restricted Stock Units 2015-02-22 4 M 0 1290 D Common Shares 1290 19026 D On February 22, 2012, the reporting person was granted 10,530 Restricted Stock Units for no monetary consideration. The Restricted Stock Units convert into (i) 2,106 common shares and (ii) cash equal to the market value of 8,424 common shares (measured at the date of vesting) upon the vesting of such Restricted Stock Units. These Restricted Stock Units were previously reported as a grant of 3,510 Restricted Stock Units converting into (i) 702 common shares and (ii) cash equal to the market value of 2,808 common shares. These amounts have been adjusted to reflect the issuer's 3-for-1 stock split paid on May 23, 2014. On February 22, 2011, the reporting person was granted 5,160 Restricted Stock Units for no monetary consideration. The Restricted Stock Units convert into (i) 2,580 common shares and (ii) cash equal to the market value of 2,580 common shares (measured at the date of vesting) upon the vesting of such Restricted Stock Units. These Restricted Stock Units were previously reported as a grant of 1,720 Restricted Stock Units converting into (i) 860 common shares and (ii) cash equal to the market value of 860 common shares. These amounts have been adjusted to reflect the issuer's 3-for-1 stock split paid on May 23, 2014. The fair market value of the cash portion was determined using the daily volume-weighted average sales price of the common shares for the five consecutive trading days prior to February 22, 2015, which was on a Sunday. 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 vest in four equal installments with the first installment vesting on February 22, 2013. Represents Restricted Stock Units held by the reporting person that vest in whole or in part in cash. The Restricted Stock Units vested in four equal installments with the first installment vesting on February 22, 2012. /s/ Wayne H. Datz, by Power of Attorney 2015-02-24