Allied World Provides Initial Estimates for Chilean Earthquake and European Windstorm Xynthia

PEMBROKE, Bermuda, March 19, 2010 - Allied World Assurance Company Holdings, Ltd (NYSE: AWH) announced today
that its initial loss estimate for the recent catastrophe event in Chile
ranges from $55 million to $75 million and its initial estimate for European
Windstorm Xynthia is $2 million. Both estimates are pre-tax and net of
reinsurance.

President and Chief Executive Officer Scott Carmilani commented, "Allied
World's estimated losses from the catastrophe events that have taken place in
the first quarter are well within our accepted risk tolerances and are in
line with our assessments of account risks and aggregate exposures for the
areas affected and compared to our models thus far. Given the size and
magnitude of the earthquake in Chile, we remain focused on helping our
customers directly affected with claims assessments and claims support during
the recovery and engineering efforts to get back to business."

Allied World's loss estimates for these events are derived from
preliminary information obtained from clients and brokers, a review of the
terms of in-force policies and contracts and from its catastrophe modeling
analysis. Actual losses from these events may vary materially from the
current estimates due to inherent uncertainties resulting from several
factors, including the preliminary nature of loss data available, potential
inaccuracies and inadequacies in the data that has been provided and the
potential for catastrophe modeling inaccuracies.

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 including those related to the ongoing financial crisis; 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