A.M. Best Co. has affirmed the financial strength rating (FSR) of A (Excellent) and issuer credit ratings (ICR) of “a” of Allied World Assurance Company, Ltd. (Bermuda) (Allied World) and its operating affiliates. In addition, A.M. Best has affirmed the ICR of “bbb”, the debt rating of “bbb” on $500 million of senior unsecured notes due 2016 and the indicative ratings of Allied World Assurance Company Holdings, Ltd. (Allied World Holdings) (Bermuda) [NYSE: AWH]. The outlook for all ratings is stable.

Concurrently, A.M. Best has affirmed the FSR of A (Excellent) and ICRs of “a” of Darwin National Assurance Company (Delaware) and Darwin Select Insurance Company (Arkansas) (collectively Darwin). These companies have now been incorporated into Allied World. (See below for a detailed listing of the companies and ratings.)

Allied World’s ratings reflect its strong risk-adjusted capitalization, stable management team and strong operating performance. In 2008, Allied World was one of only a few Bermuda-based property/casualty insurers to grow shareholders’ equity despite the market turmoil and catastrophe events. During 2008, Allied World established a U.S. reinsurance company, expanded its presence in Europe and Hong Kong and acquired Darwin, which provided a book of U.S. small account primary healthcare and professional liability business. Darwin represents a material component of Allied World’s primary insurance operations in the United States, and these two organizations now have been integrated into Allied World’s operations, providing for significant efficiencies and controls.

Partially offsetting these positive ratings factors is the current soft pricing environment in addition to the unstable financial markets. Although, in A.M.