X0306 4 2017-02-22 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 2017-02-22 4 M 0 931 0.00 A 17406 D Common Shares 2017-02-22 4 D 0 186 53.3769 D 17220 D Common Shares 2017-02-22 4 F 0 359 53.12 D 16861 D Common Shares 76917 I By Trust Restricted Stock Units 2017-02-22 4 M 0 931 D Common Shares 931 6087 D On February 22, 2016, the reporting person was granted 3,725 Restricted Stock Units for no monetary consideration. The Restricted Stock Units convert into (i) 2,980 common shares and (ii) cash equal to the market value of 745 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 common shares for the five consecutive trading days up to and including February 22, 2017. 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 76,917 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, 2017. Represents Restricted Stock Units held by the reporting person that vest in whole or in part in cash. /s/ Theodore Neos, by Power of Attorney 2017-02-24