Allied World's Barry Zurbuchen to Speak at the Casualty Actuarial Society's Seminar on Reinsurance

PEMBROKE, Bermuda, May 4, 2010 - Allied World Assurance Company Holdings, Ltd (NYSE: AWH) announced today
that Barry Zurbuchen, Senior Vice President & Head of Enterprise Risk
Modeling for Allied World Assurance Company, Ltd is speaking at the Casualty
Actuarial Society's Seminar on Reinsurance. The event takes place on May 6 &
7, 2010 at the Crowne Plaza Times Square Hotel in New York City, New York.
Mr. Zurbuchen will speak on May 6 at 2:30pm (EDT) as part of a panel
entitled, "What Makes a Good Economic Capital Model?"

As Senior Vice President & Head of Enterprise Risk Modeling, Mr.
Zurbuchen is responsible for all aspects of enterprise risk modeling
including development and parameterization of Allied World's Economic Capital
Model and monitoring Allied World's aggregation of catastrophes, developing
pricing mechanisms to ensure risk adjusted returns on capital are met,
monitoring Allied World's total corporate risk to ensure it is within the
company's risk appetite, and making strategic recommendations to enhance
shareholder value. He joined Allied World in November 2002, moving from his
previous position as Vice President at Aon Re in Chicago. At Aon Re, Mr.
Zurbuchen worked with clients and brokers structuring and pricing reinsurance
placements for all property and casualty lines and performing dynamic
financial analysis of client portfolios. Prior to joining Aon Re, he held a
variety of positions at CNA, including Assistant Vice President responsible
for the pricing of all large commercial casualty accounts. Mr. Zurbuchen
graduated with Highest Departmental Distinction from the University of
Illinois with a Bachelor's of Science in Actuarial Science.

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, both of Allied World Assurance Company Holdings, Ltd