X0306 4 2015-02-22 0 0001163348 Allied World Assurance Co Holdings, AG AWH 0001543666 McElroy John Justin ALLIED WORLD ASSURANCE CO. HOLDINGS, AG GUBELSTRASSE 24, PARK TOWER, 15TH FLOOR ZUG V8 6300 SWITZERLAND 0 1 0 0 COO Common Shares 2015-02-22 4 M 0 1680 0.00 A 11741 D Common Shares 2015-02-22 4 M 0 882 0.00 A 12623 D Common Shares 2015-02-22 4 D 0 1785 40.4481 D 10838 D Common Shares 2015-02-22 4 F 0 382 40.54 D 10456 D Common Shares 76917 I By Trust Restricted Stock Units 2015-02-22 4 M 0 1680 D Common Shares 1680 13221 D Restricted Stock Units 2015-02-22 4 M 0 882 D Common Shares 882 12339 D On February 22, 2012, the reporting person was granted 6,726 Restricted Stock Units for no monetary consideration. The Restricted Stock Units convert into (i) 1,344 common shares and (ii) cash equal to the market value of 5,382 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 2,242 Restricted Stock Units converting into (i) 448 common shares and (ii) cash equal to the market value of 1,794 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 3,510 Restricted Stock Units for no monetary consideration. The Restricted Stock Units convert into (i) 1,755 common shares and (ii) cash equal to the market value of 1,755 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 1,170 Restricted Stock Units converting into (i) 585 common shares and (ii) cash equal to the market value of 585 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. Represents shares held by an irrevocable trust for the benefit of the reporting person's children. 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