OLDWICK, N.J.--(BUSINESS WIRE)--A.M. Best has commented that the financial strength rating (FSR) of A+ (Superior) and the issuer credit ratings (ICR) of “aa” of the members of Houston Casualty Group (HCC) remain unchanged following the recent acquisition announcement between HCC Insurance Holdings, Inc. (HCC Holdings) (Dover, DE) and Tokio Marine Holdings, Inc. (TMHD). Additionally, the debt rating of “a” for HCC Holdings’ senior unsecured notes remains unchanged. On June 10, 2015, it was annou