Allied World Schedules Second Quarter 2010 Earnings Announcement and Conference Call

PEMBROKE, Bermuda, July 1, 2010 - Allied World Assurance Company Holdings, Ltd (NYSE: AWH) today announced
that it will release its financial results for the second quarter ended June
30, 2010, after the close of market on Thursday, August 5, 2010.

Scott Carmilani, President and Chief Executive Officer, and Joan Dillard,
Chief Financial Officer, will host a conference call on Friday, August 6,
2010 at 8:00 am (Eastern Time) to discuss the second quarter 2010 financial
results. This call will include a question and answer session.

The conference call can be accessed by dialing +1-866-843-0890 (U.S. and
Canada callers) or +1-412-317-9250 (international callers) and entering the
passcode 7313881 approximately ten minutes prior to the call. A live webcast
of the call will be available online at www.awac.com. A replay of the
call will be available through Friday, August 20, 2010 by dialing
+1-877-344-7529 (U.S. and Canada callers) or +1-412-317-0088 (international
callers) and entering the passcode 442249. In addition, the webcast will
remain available online through Friday, August 20, 2010 at
www.awac.com.

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.

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