A.M. Best Co. has affirmed the financial strength rating (FSR) of A++ (Superior) and issuer credit ratings (ICR) of “aa+” of the Chubb Group of Insurance Companies (Chubb Group) and its property/casualty members. Concurrently, A.M. Best has affirmed the ICR of “aa-”, senior debt ratings of “aa-”, the debt rating of “a” on junior subordinated debt, the indicative ratings on securities and the “AMB-1+” on the commercial paper of Chubb Group’s publicly traded holding company, The Chubb Corporation (Chubb Corp) [NYSE: CB]. In addition, A.M. Best has affirmed the FSR of A++ (Superior) and ICR of “aa+” of Chubb Atlantic Indemnity Ltd. (Chubb Atlantic) (Pembroke, Bermuda). The outlook for all ratings is stable. All companies are domiciled in Warren, NJ, except where specified. (See below for a detailed list of the companies and ratings.) The ratings reflect Chubb Group’s superior risk-adjusted capitalization, excellent underwriting and overall operating performance and the sustainable competitive advantages within its specialty and upscale personal insurance businesses. The ratings also recognize Chubb Group’s comprehensive and proactive enterprise risk management, disciplined underwriting, strong franchise recognition and access to the capital markets through Chubb Corp. These rating factors are partially offset by Chubb Group’s historical adverse loss reserve development associated with its asbestos and environmental (A&E) liabilities. Given Chubb Group’s leading market position, specialty niche underwriting focus, prudent balance sheet liquidity, strong operating cash flows and excellent risk-adjusted capitalization, A.M. Best considers the group favorably positioned and sufficiently capitalized to absorb these challenges and those posed by the continued competitive market. Chubb Atlantic’s ratings recognize its solid capitalization and the implicit and explicit support provided by Chubb Corp. This financial support is evidenced by the capital contributions in recent years to support Chubb Atlantic’s operations, as well as the business of its subsidiary, Chubb do Brasil Companhia de Seguros. Furthermore, Chubb Atlantic is the beneficiary of sizable irrevocable letters of credit issued by banks on behalf of Chubb Corp. The ratings also acknowledge Chubb Atlantic’s strategic importance within the Chubb Group, including quota share reinsurance assumed from affiliates. These positive rating factors are partially offset by Chubb Atlantic’s volatility in underwriting performance in prior years, largely due to adverse loss reserve development.