X0306 4 2013-02-19 0 0001163348 Allied World Assurance Co Holdings, AG AWH 0001368443 Carmilani Scott A ALLIED WORLD ASSURANCE CO. HOLDINGS, AG LINDENSTRASSE 8 BAAR/ZUG V8 CH-6340 SWITZERLAND 1 1 0 0 President, CEO and Chairman Common Shares 2013-02-19 4 A 0 116876 0.00 A 426784 D Common Shares 2013-02-19 4 F 0 61661 87.73 D 365123 D Common Shares 43000 I By Trust Restricted Stock Units 2013-02-19 4 A 0 17067 A Common Shares 17067 17067 D Represents the Company's Common Shares that were earned pursuant to performance-based awards granted in 2008 and 2010 for no monetary consideration and which vested at 150% and 103%, respectively, of target based on the achievement of pre-established performance criteria during the applicable performance period established under the Company's Third Amended and Restated Long-Term Incentive Plan and its Third Amended and Restated 2004 Stock Incentive 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. Represents 43,000 shares held by an irrevocable trust for the benefit of the reporting person's spouse and children. Grant of Restricted Stock Units for no monetary consideration. Restricted Stock Units convert into cash equal to the market value of 17,067 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