This is usually the third- or fourth-highest rating that a rating agency allocates to a security or insurance carrier. It is frequently the lowest investment-grade rating, but it indicates that the issuer is quite stable with comparatively low default risk.

The ratings allocated by the several ratings agencies are on the basis of the insurer's or issuer's creditworthiness. This rating can thus be considered as a direct measure of the probability of default. Though, priority of payment and credit stability are also taken into the rating.