OREANDA-NEWS. A.M. Best has placed under review with developing implications the financial strength ratings (FSR) of A+ (Superior) and the issuer credit ratings (ICR) of “aa-” of Arch Reinsurance Ltd. (Hamilton, Bermuda) [Nasdaq: ACGL] and its strategic affiliates. Additionally, A.M. Best has also placed under review with developing implications the ICRs of “a-” and the issue ratings of Arch Capital Group Ltd. (Hamilton, Bermuda) and Arch Capital Group (US) Inc. (Delaware)