OLDWICK, N.J.--(BUSINESS WIRE)-- A.M. Best Co. has affirmed the financial strength rating (FSR) of A (Excellent) and issuer credit ratings (ICR) of "a" of the property/casualty subsidiaries of AmTrust Financial Services, Inc. (AFSI) (New York, NY) [NASDAQ: AFSI] also known as AmTrust Group (AmTrust). Concurrently, A.M. Best has affirmed the ICR of "bbb" of AFSI. The outlook for all ratings is stable. (See below for a detailed list of the companies.)