An insurer's promise is only as good as its ability to pay. Independent rating organizations, such as AM Best, Fitch, Moody's and Standard and Poor's (S&P), study insurers' finances and publish ratings.
A rating is an opinion of the insurer's financial strength and its ability to meet its obligations.
It is not a promise that any particular claim will be paid. That still depends on the policy terms and the facts of the loss.
It is not approval by the Department of Insurance, and it says nothing about price.
Each agency uses its own scale. AM Best's top grade is A++, and S&P's top insurer financial strength grade is AAA. Because the scales are separate, the symbols cannot be compared letter by letter across agencies.