OLDWICK, N.J.--(BUSINESS WIRE)--A.M. Best has upgraded the financial strength rating to A- (Excellent) from B++ (Good) and the issuer credit rating to “a-“ from “bbb+”of Triangle Insurance Company, Inc. (Triangle) (Enid, OK). The outlook for both ratings has been revised to stable from positive. The rating upgrade reflects Triangle's excellent risk-adjusted capitalization achieved through significantly improved operating profitability in recent years, management’s strong niche market knowledge