AM Best has affirmed the credit ratings of re/insurer Allied World Assurance Co Holdings Ltd and its subsidiaries, citing the group’s strong operating performance and balance sheet strength.

The ratings agency affirmed Allied World’s Financial Strength Rating of A+ (Superior) and the Long-Term Issuer Credit Ratings of “aa-” (Superior) for its operating affiliates. It also affirmed the Long-Term Issuer Credit Ratings of “a-” (Excellent) for Allied World Holdings and its downstream holding company, Allied World Assurance Co Holdings I Ltd. The outlook for all ratings remains stable.

AM Best said the ratings reflected Allied World’s “strongest” level of balance sheet strength, as well as strong operating performance, a favourable business profile and appropriate enterprise risk management.

The agency said Allied World had produced strong underwriting results in recent years as it shifted its focus towards casualty and speciality lines while reducing exposure to property catastrophe business.

AM Best added that the company had benefited from an expense ratio advantage as it expanded operations and from higher net investment income after reallocating assets into higher-yielding bonds.

The affirmed ratings apply to a number of Allied World subsidiaries, including Allied World Assurance Co Ltd, Allied World Specialty Insurance Co, Allied World Insurance Co and Allied World Assurance Co (United States) Inc.

Allied World, headquartered in Bermuda, provides has operations in North America, Europe and Asia-Pacific.