Ratings on life insurance carriers are actually financial strength ratings based on a review of the financial statements of an insurer by an independent financial rating service.
There are several rating services that review insurers, including AM Best, Standard & Poor's, and Moody's, among others.
The financial strength rating is an indicator of the insurance carrier's ability ability to meet their financial obligations and pay their claims.
The higher the rating, the more financially secure the insurer.
For instance, an "A++" Superior rating is the highest available from AM Best and means the insurer is financially sound and able to meet their financial obligations.
Here is a list of some of the leading life insurance carriers in America.