Des Moines-based American Enterprise Group Inc. announced that insurance rating agency AM Best has upgraded the Financial Strength Rating of its six insurance company subsidiaries to A (Excellent) from A- (Excellent). These subsidiaries operate under the brands of American Republic, Medico and Great Western Insurance Co. With the upgrade, the outlook of these credit ratings has been revised to stable from positive. “During a time when financial strength and stability is even more critical, we are especially honored to have AM Best acknowledge our strong financial profile with an upgrade,” American Enterprise CEO Tom Swank said in a news release. AM Best ratings are based on a company’s financial strength, operational performance over several years, business profile and risk management practices.