A.M. Best Co. has assigned a debt rating of “bbb” to the recently issued $300 million 5.5% senior unsecured notes due 2020 of Allied World Assurance Company Holdings, Ltd (Allied World) (Bermuda) (NYSE: AWH). The assigned outlook is stable.

The proceeds from the debt offering will be used for general corporate purposes. The debt-to-adjusted capital ratio and fixed charge coverage remain comfortably within the range that is commensurate with the assigned rating.

Allied World is a diversified property/casualty insurer/reinsurer with significant geographic reach. The company has strong risk-adjusted capitalization, an experienced management team and a historically strong operating performance.

The principal methodology used in determining these ratings is Best’s Credit Rating Methodology -- Global Life and Non-Life Insurance Edition, which provides a comprehensive explanation of A.M. Best’s rating process and highlights the different rating criteria employed. Additional key criteria utilized include: “Risk Management and the Rating Process for Insurance Companies”; “Understanding BCAR for Property/Casualty Insurers”; and “A.M. Best’s Ratings & the Treatment of Debt.” Methodologies can be found at www.ambest.com/ratings/methodology.

Founded in 1899, A.M. Best Company is the world's oldest and most authoritative insurance rating and information source. For more information, visit www.ambest.com.