An insurance policy is a promise that may need to be kept years from now. Financial strength ratings are independent opinions on whether an insurer will be able to keep that promise. Four agencies dominate insurer ratings in the US: AM Best, S&P Global Ratings, Moody's and Fitch Ratings. Their scales look different, so here is how to read them side by side.
What a financial strength rating measures
AM Best defines its Financial Strength Rating (FSR) as an independent opinion of an insurer's financial strength and ability to meet its ongoing insurance policy and contract obligations. The rating applies to the insurance company, not to a specific policy. The other agencies' insurer financial strength ratings have the same focus: the ability to pay policyholder claims, as opposed to the credit rating of the holding company's bonds.
Ratings are opinions, not guarantees. AM Best, for example, evaluates balance sheet strength, operating performance, business profile and enterprise risk management, and stresses that a rating is a forward-looking opinion that cannot be considered a guarantee. Ratings can be upgraded, downgraded or withdrawn.
AM Best: the most widely used scale for US insurers
| Category | Ratings | AM Best's description |
|---|---|---|
| Superior | A++, A+ | Superior ability to meet ongoing insurance obligations |
| Excellent | A, A- | Excellent ability |
| Good | B++, B+ | Good ability |
| Fair | B, B- | Fair ability; financial strength vulnerable to adverse changes |
| Marginal | C++, C+ | Marginal ability; vulnerable |
| Weak | C, C- | Weak ability; very vulnerable |
| Poor | D | Poor ability; extremely vulnerable |
AM Best also uses status codes: E for insurers placed under regulatory supervision (conservation or rehabilitation) and F for insurers placed in liquidation after a finding of insolvency. Ratings are usually published together with an outlook, such as "stable," that signals the likely direction of the rating.
S&P Global Ratings
S&P's insurer financial strength scale runs from AAA (extremely strong financial security characteristics) through AA (very strong), A (strong) and BBB (good) down to BB (marginal), B (weak), CCC (very weak) and CC (extremely weak). SD and D indicate default on policy obligations. Ratings from AA to CCC can carry a plus or minus. Insurers rated BB or lower are described as having vulnerable characteristics.
Moody's and Fitch
Moody's insurance financial strength ratings use 21 notches, from Aaa (exceptional) through Aa1–Aa3 (excellent), A1–A3 (good), Baa1–Baa3 (adequate), Ba1–Ba3 (questionable), B1–B3 (poor), Caa1–Caa3 (very poor), Ca (extremely poor) to C (lowest). The numbers 1, 2 and 3 show whether a company sits at the higher, middle or lower end of its category.
Fitch's insurer financial strength ratings range from AAA to C, with plus and minus modifiers from AA through CCC. Fitch describes the AA category as "very strong," the same word S&P uses for that level.
One insurer, four ratings
Because the scales differ, it helps to see how one company is rated by all four agencies. Insurers usually publish this on their own websites:
| Company (as published) | AM Best | S&P | Moody's | Fitch |
|---|---|---|---|---|
| Metropolitan Life Insurance Company (as of July 6, 2026) | A+ | AA- | Aa3 | AA- |
| Jackson National Life Insurance Company (as of February 18, 2026) | A | A | A3 | A |
In these examples, AM Best's A+ coincided with AA- at S&P and Fitch and Aa3 at Moody's, while AM Best's A coincided with A at S&P and Fitch and A3 at Moody's. These pairings are illustrations, not official equivalences: each agency uses its own methodology, and the same letter does not mean the same thing on every scale.
How to use ratings when you buy insurance
- Check the insuring company, not just the brand. Groups have several legal entities, sometimes with different ratings. The name on your policy is what counts.
- Match the rating to the length of the promise. For a six-month auto policy, a solid rating and good claims service matter. For permanent life insurance, annuities or long-term care, prefer the strongest ratings you can find, because the insurer must stay healthy for decades.
- Watch the outlook and recent changes. A downgrade or negative outlook is an early warning.
- Combine ratings with other data. Look at complaint records and regulatory capital as well (see how to check insurer reliability).
- Know the safety net. If an insurer fails, state guaranty associations protect policyholders up to legal limits (see what happens when an insurer fails).
Bottom line
Use ratings as a filter: shortlist companies with ratings in the upper categories of at least one major agency, then compare coverage, price and service. You can look up AM Best ratings on ambest.com and on most insurers' websites. Polis Re can help you compare rated insurers for life, annuity, home or business coverage; request a quote.