The objective of Best's rating system is to provide an opinion of an insurer's financial strength and ability to meet ongoing obligations to policyholders. A.M. Best's opinions are derived from the evaluation of a company's balance sheet strength, operating performance and business profile as compared to Best's quantitative and qualitative standards. While Best's Ratings reflect an independent opinion of a company's financial strength and ability to meet its ongoing obligations to policyholders, they are not a warranty, nor are they a recommendation of a specific policy form, contract, rate or claim practice.

The scale includes 16 different rating levels ranging from A++ to S, grouped into categories. For example the Superior category contains the levels A++ and A+, while the A and A- ratings appear in the Excellent category. B++ and B+ ratings appear in the Good category.

Best's Ratings ranging from A++ to B+ are considered Secure. A.M. Best describes Secure insurers as having a strong or good ability to meet their long-term obligations to members and policyholders. Insurers assigned Secure ratings maintain a level of financial strength that can withstand unfavorable changes in the business, economic, or regulatory environment.