MEXICO CITY--(BUSINESS WIRE)-- A.M. Best has upgraded the Financial Strength Rating to A (Excellent) from A- (Excellent), the Long-Term Issuer Credit Rating to "a" from "a-" and the Mexico National Scale Rating to "aaa.MX" from "aa.MX" of MAPFRE Fianzas, S.A. (MAPFRE Fianzas) (Mexico City, Mexico). The outlook of these Credit Ratings (ratings) is stable.