Allied World’s Chief Risk Officer to Participate in Panel at ERM and Capital Modeling Conference, May 27, 2009

PEMBROKE, Bermuda - Allied World Assurance Company Holdings, Ltd (NYSE: AWH) today announced that Ralph Rathjen, Chief Risk Officer, will be participating in a panel at Aon Benfield’s ERM and Capital Modeling Conference in Chicago on May 27, 2009. The panel will discuss ERM implementation issues and priorities over the next 12-18 months.

At Allied World, Mr. Rathjen is responsible for managing the Company’s comprehensive risk management process, including identification, measurement, management and monitoring of risk exposures as well as assisting in optimizing the company’s risk-adjusted returns. Ralph has over 25 years of insurance and reinsurance experience.

Previous to his work with Allied World, Mr. Rathjen was Senior Vice President, Actuarial of American International Company Ltd. Prior to this, Mr. Rathjen was a Consulting Actuary with Tillinghast/Towers Perrin where he managed a wide variety of consulting assignments including modeling and pricing for specialty lines. Mr. Rathjen holds a Masters degree in Actuarial Science from the University of Nebraska. He is a Fellow of the Casualty Actuarial Society and holds the CPCU, ARM and ARe Insurance 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, the United States, Europe and Hong Kong. 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 the ability to recognize the benefits of the Darwin Professional Underwriters, Inc. acquisition; 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.

Source: Allied World Assurance Company Holdings, Ltd

Media, Faye Cook, VP, Marketing & Communications, +1-646-794-0543, 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