Allied World's Anthony Kashuba Promoted to Senior Vice President; European General Casualty Manager

PEMBROKE, Bermuda, May 20, 2010 - Allied World Assurance Company Holdings, Ltd (NYSE: AWH) announced
today that Anthony Kashuba, Vice President and General Casualty Team Leader
in Bermuda has been promoted to Senior Vice President and European General
Casualty Manager. He will work from the London office, effective May 22,
2010, and will be responsible for the strategic oversight of Allied World's
European General Casualty operations.

Frank D'Orazio, President, Bermuda and International Insurance,
commented, "We are pleased to announce Anthony will manage our European
General Casualty team. His knowledge and expertise are invaluable, and we
look forward to his future success in the European marketplace."

Mr. Kashuba joined Allied World in 2008. He has 20 years of global
insurance and reinsurance experience, and has served in various underwriting
positions in the United States, Hong Kong, Germany and Bermuda. His
underwriting experience includes primary casualty insurance, including loss
sensitive programs, facultative reinsurance and excess casualty insurance.
Mr. Kashuba holds a Bachelors of Arts Degree in History from Alfred
University and has received his CPCU and ARe designations.

About Allied World Assurance Company

Allied World Assurance Company Holdings, Ltd, through its subsidiaries,
is a global provider of innovative property, casualty and specialty insurance
and reinsurance solutions, offering superior client service through offices
in Bermuda, Europe, Hong Kong, Singapore and the United States. Our insurance
and reinsurance subsidiaries are rated A (Excellent) by A.M. Best Company.
For further information on Allied World, please visit our website at
www.awac.com.

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; investigations of market
practices and related settlement terms; 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.

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