A.M. Best
Weiss
Moody's
Fitch
Standard & Poor's
It may make sense to use multiple rating systems to measure the insurance companies you are interested in comparing for your coverage.
Most online life insurance quote providers will show you the premiums offered by carrier and the insurance carriers financial strength rating from AM Best Company, the leading financial rating service of life insurance companies.
Each year the III.org (Insurance Information Institute) issues a list of the largest life insurance companies in America by written premium and individual life insurance policies issued. Here is the list of top rated life insurance companies.