X0306 4 2013-02-19 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 2013-02-19 4 A 0 6180 0.00 A 18598 D Common Shares 2013-02-19 4 F 0 3024 87.73 D 15574 D Restricted Stock Units 2013-02-19 4 A 0 2501 A Common Shares 2501 2501 D Represents the Company's Common Shares that were earned pursuant to a 2010 performance-based award for no monetary consideration and which vested at 103% of target based on the achievement of pre-established performance criteria during the applicable three-year performance period established under the Company's Third Amended and Restated 2004 Stock Incentive Plan. Includes 175 Common Shares acquired on December 31, 2012 pursuant to the Company's Amended and Restated 2008 Employee Share Purchase Plan. Exclusively represents shares withheld by the Company with respect to the payment of withholding tax liability incurred upon the vesting of performance-based awards. Grant of Restricted Stock Units for no monetary consideration. Restricted Stock Units convert into cash equal to the market value of 2,501 Common Shares (measured at the date of vesting) upon the vesting of such Restricted Stock Units. The Restricted Stock Units vest in four equal installments with the first installment vesting on February 19, 2014. /s/ Wayne H. Datz, by Power of Attorney 2013-02-21