OLDWICK, N.J.--(BUSINESS WIRE)--AM Best has commented that the Credit Ratings (ratings) 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 (see listing below) remain unchanged following its announcement that it has entered into a definitive agreement to acquire all of The Cigna Group’s (Cigna) (headquartered in Bloomfield, CT) [NYSE: CI] Medicare Advantage, ...