Allied World Appoints Senior Staff; Bolsters International Strategy

ZUG, Switzerland, May 31, 2011 -

Allied World Assurance Company Holdings, AG (NYSE: AWH) announced today
that Ed Moresco has been appointed Senior Vice President, Bermuda &
International Product Line Manager, Professional Lines, and Ian Theato has
been appointed Senior Vice President, International Business Development.
Both appointments are effective immediately.

Mr. Moresco will be based in Allied World's Bermuda office and will
oversee the Bermuda and International Professional Lines division,
responsible for the underwriting, marketing and management of Allied World's
Bermuda, Europe, and Asia Professional Lines insurance platforms. He has 15
years of experience in the insurance industry and has been an integral part
of Allied World's Professional Lines division in the U.S. since joining the
company in 2008. Prior to Allied World, Mr. Moresco was Senior Vice President
for Financial Lines at AIG Small Business. He received his undergraduate
degree from York College of Pennsylvania.

Mr. Theato will be based in Allied World's London office and will be
responsible for distribution management and regional business development for
Allied World's international insurance platforms. He joined Allied World in
2003 to create and lead the European Professional Lines division in London,
and in 2008 was appointed to Senior Vice President, Bermuda & International
Product Line Manager, Professional Liability. Prior to Allied World, Mr.
Theato worked at Gulf Insurance where he managed a global portfolio of
Professional Lines. He has over 25 years of experience in the industry.

Frank D'Orazio, President, Bermuda & International Insurance commented,
"We wish Ed and Ian success in their new roles within Allied World's Bermuda
and International platforms, and look forward to their future contributions
to the company."

About Allied World Assurance Company

Allied World Assurance Company Holdings, AG, through its subsidiaries, is
a global provider of innovative property, casualty and specialty insurance
and reinsurance solutions, offering superior client service through a global
network of branches and affiliates. Our insurance and reinsurance
subsidiaries are rated A (Excellent) by A.M. Best Company, and our Lloyd's
Syndicate 2232 is rated A+ (Strong) by Standard & Poor's and Fitch. Please
visit our website at www.awac.com for further information on Allied
World.

Cautionary Statement Regarding Forward-Looking Statements

Any forward-looking statements made in this press release reflect our
current views with respect to future events and financial performance and are
made pursuant to the safe harbor provisions of the Private Securities
Litigation Reform Act of 1995. Such statements involve risks and
uncertainties, which may cause actual results to differ materially from those
set forth in these statements. For example, our forward-looking statements
could be affected by pricing and policy term trends; increased competition;
the impact of acts of terrorism and acts of war; greater frequency or
severity of unpredictable catastrophic events; negative rating agency
actions; the adequacy of our loss reserves; the company or its subsidiaries
becoming subject to significant income taxes in the United States or
elsewhere; changes in regulations or tax laws; changes in the availability,
cost or quality of reinsurance or retrocessional coverage; adverse general
economic conditions; and judicial, legislative, political and other
governmental developments, as well as management's response to these factors,
and other factors identified in our filings with the U.S. Securities and
Exchange Commission. You are cautioned not to place undue reliance on these
forward-looking statements, which speak only as of the date on which they are
made. We are under no obligation (and expressly disclaim any such obligation)
to update or revise any forward-looking statement that may be made from time
to time, whether as a result of new information, future developments or
otherwise.

Faye Cook, VP, Marketing & Communications, +1-441-278-5406, faye.cook at awac.com, Keith J. Lennox, Investor Relations Officer, +1-646-794-0750, keith.lennox at awac.com