OLDWICK, N.J.–(BUSINESS WIRE)–A.M. Best has upgraded the Financial Strength Rating (FSR) to A (Excellent) from A- (Excellent) and the Long-Term Issuer Credit Ratings (Long-Term ICR) to “a” from “a-” of the wholly owned subsidiaries of Medical Professional Mutual Insurance Company (ProMutual) (Boston, MA): MHA Insurance Company (MHA) (East Lansing, MI), Washington Casualty Company (Washington Casualty) (Maple Valley, WA) and Preferred Professional Insurance Company (PPIC) (Omaha, NE). The outl
