OREANDA-NEWS. A.M. Best has downgraded the financial strength rating (FSR) to A (Excellent) from A+ (Superior) and the issuer credit ratings (ICR) to “a+” from “aa-” of Health Care Service Corporation, a Mutual Legal Reserve Company (d/b/a Blue Cross Blue Shield of Illinois/Texas/New Mexico/Oklahoma/Montana) (HCSC) (headquartered in Chicago, IL) and its subsidiaries, HCSC Insurance Services Company (Chicago, IL) and GHS Health Maintenance Organization (Tulsa, OK). Concurrently, A.M. Best has downgraded the issue rating to “a” from “a+” on HCSC’s existing $500 million 4.7% senior unsecured notes, due 2021 (approximately $345 million outstanding). The outlook for each of these ratings is stable.