A.M. Best Co. has assigned a debt rating of “bbb” to the $325 million 6.75% Series C preferred shares of Arch Capital Group Ltd. (Arch) (Hamilton, Bermuda) [NYSE: ACGL]. The assigned outlook is stable. The proceeds from the issuance will be used by Arch to redeem its Series A and B preferred securities. This issuance would not represent a material impact on the organization’s overall capital structure and have no impact on the company’s existing financial strength ratings. The methodology used in determining these ratings is Best’s Credit Rating Methodology, which provides a comprehensive explanation of A.M. Best’s rating process and contains the different rating criteria employed in the rating process. Key criteria utilized include: “Risk Management and the Rating Process for Insurance Companies”; “Understanding Universal BCAR”; “Catastrophe Analysis in A.M. Best Ratings”; and “A.M. Best’s Ratings & the Treatment of Debt.” Best’s Credit Rating Methodology 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. Copyright © 2012 by A.M. Best Company, Inc. ALL RIGHTS RESERVED.