X0304 4 2012-02-23 0 0001163348 Allied World Assurance Co Holdings, AG AWH 0001368328 Dupont Wesley D ALLIED WORLD ASSURANCE CO. HOLDINGS, AG LINDENSTRASSE 8 BAAR/ZUG V8 CH-6430 SWITZERLAND 0 1 0 0 EVP, Gen. Counsel & Corp. Sec. Common Shares 2012-02-23 4 S 0 5000 67.5145 D 53621 D The sale of Common Shares reported in this Form 4 were for tax purposes. Represents a weighted average sale price: the sales prices range from $67.50 to $67.55. Upon request, the full sale information regarding the number of shares sold at each price increment will be provided to the Commission, the issuer or a security holder of the issuer. /s/ Wayne H. Datz, Power of Attorney 2012-02-27