• AM. The best rating is the rating published by A.M. The best company among all life, property and casualty insurers registered in the United States and US affiliates of foreign property insurers groups operating in the United States. Ratings are often used to determine the solvency, suitability, track record, and financial strength of insurance companies. Other rating agencies include Standard & Poor’s, Conning & Company, Fitch and Moody’s.