AM Best Ratings Explained: What Insurance Company Ratings Mean

An AM Best rating is an independent view of how strong an insurer's finances are and whether they can meet their current ongoing policy claim obligations. The Best's Financial Strength Ratings (A++) range from the highest level (Superior) to D (the lowest), as follows:

• A++, A+ - Superior
• A, A- - Excellent
• B++, B+ - Good
• B, B- - Fair
• C++, C+ - Marginal
• C, C- - Weak
• D - Poor

Separate non-rating designations E, F, and S flag insurers under regulatory supervision, in liquidation, or with a suspended rating.

The rating answers one narrow question: will this carrier still be solvent and paying when your claim arrives, possibly years after you bought the policy? That makes it one of the few numbers on a proposal worth checking before you look at price.

What is an AM Best rating?

An AM Best rating is a letter grade that AM Best, a credit rating agency founded in 1899 that specializes in insurance, assigns to an insurer after evaluating its ability to meet ongoing policy obligations. AM Best's Guide to Best's Financial Strength Ratings defines the Best's Financial Strength Rating as an independent opinion of financial strength and claims-paying ability.^[1] It measures solvency, not customer service or price.

Best's credit rating methodology relies on four building blocks for an opinion: 1) balance sheet strength, 2) operating performance, 3) business profile, and 4) enterprise risk management (ERM).^[2] The credit rating starts with the first of these: the company's financial health as measured by its balance sheet strength. AM Best is clear about the limits of an FSR. A financial strength rating is not a recommendation to purchase, retain, or cancel a policy. It is also no guarantee against insolvency.

What do AM Best rating letters mean?

AM Best rating letters map to seven categories of claims-paying ability. Superior (A++ and A+) and Excellent (A and A-) mark the strongest carriers and cover most of the standard market. Good (B++ and B+) still describes a secure insurer. The tone changes at Fair (B and B-), where the definition first mentions vulnerability, and grows harsher through Marginal (C++ and C+), Weak (C and C-), and Poor (D). The categories, not the individual letters, are the units AM Best defines:

The plus and minus signs are notches inside a category, so A- is still Excellent and B+ is still Good. A few symbols below D are not ratings at all, but non-rating designations: E for an insurer placed into conservation or rehabilitation, F for one in liquidation after an insolvency finding, and S for a rating suspended when AM Best lacks the information to evaluate a sudden event. NR means not rated. An NR is worth a phone call, since some insurers never sought a rating while others let one lapse ahead of bad news.

Is a B++ rating good?

Yes, literally. Many buyers see a B anywhere in a rating and assume the carrier is limping, but that reading is wrong. B++ and B+ ratings are categorized by AM Best as Good, the third of its seven categories and inside its secure range. B and B- ratings are the ones categorized as Fair and fit into their vulnerable to adverse underwriting and economic conditions, which is where the genuine caution starts.

In practice, much of the market prices in a higher floor. Construction insurance specifications conventionally require A- VII or better from AM Best, a floor lender mortgagee clauses echo, and excess and umbrella underwriters demand rated paper beneath them before they will sit above your excess liability program. A B++ policy can be perfectly sound and still fail the insurance specifications on your next job.

Why do AM Best ratings matter for surplus lines buyers?

The rating is most important when there is little to nothing for you to fall back on. Where an admitted carrier has a participation in their respective states guaranty fund, if the insurer fails, this fund pays those covered claims. Most states cap an individual's recovery from the fund at $300,000 per claim or the policy limit, whichever is less, as referenced by the National Conference of Insurance Guaranty Funds.^[3] With no guaranty fund behind it at all, the only source for reimbursement when a surplus lines carrier becomes insolvent mid-claim is the carrier's own balance sheet.

Eligibility rules narrow the field without grading quality. Under the federal Nonadmitted and Reinsurance Reform Act of 2010, a US-domiciled surplus lines insurer generally must hold at least $15 million in capital and surplus,^[4] and non-US insurers typically appear on the NAIC Quarterly Listing of Alien Insurers.^[5] Those are solvency floors, not quality grades. The rating separates a merely eligible carrier from a strong one, which is why your surplus lines broker should quote it as routinely as the premium and recheck it at renewal, since a downgrade below A- can trip loan covenants and contract requirements mid-term.

How do you look up an insurance company's AM Best rating?

You can find the current rating of virtually every insurance company in just a couple of minutes by using the Rating Search feature available for free at www.ambest.com after registering. You will have to know exactly how to search since an insurance company may be part of an insurance group which includes many different entities with their own ratings and they do not always share one rating. Therefore, you need the exact legal entity name on your declarations page as opposed to the Group Name.

1. Find the exact writing company name

   Take the insurer's full legal name from your declarations page or certificate, not the trade name, since a group may write your policy through a subsidiary rated differently than the flagship.

2. Search the rating on ambest.com

   Search for that exact legal name of the insurance company on Ambest.com and verify that the domicile state matches your paperwork. This will ensure you do not get ratings for another related company.

3. Read the full rating unit

   Make a note of the rating (letter grade), the outlook, and the Financial Size Category (Roman numeral indicating the surplus amount). Class VII includes $50 million to $100 million. Class XV has $2 billion or higher. That is why spec sheets have "A- VII or better".

4. Check this rating upon renewing your policy

   Verify the rating at each renewal, since a carrier that was A- at binding can be downgraded mid-term.

The other part of this check would be your State Insurance Department to see if they allow the company to write policies or if the company is surplus lines eligible and to look for complaints filed against them which are not accounted for in the financial rating.

AM Best ratings of major insurers (as of July 2026)

Most large national carriers currently hold grades in AM Best's top two categories, Superior and Excellent. The grades below are each insurer group's published Best's Financial Strength Rating as of July 2026, compiled from AM Best rating announcements, carrier disclosures, and annual SEC filings. A rating applies to a named rating unit, and individual writing companies within a group can carry different grades, so always verify the exact entity on your declarations page. Carriers are listed alphabetically:

Ratings change as AM Best completes its reviews, so please go to ambest.com and look up your specific writing company to obtain the most current rating prior to relying on the information contained within this table.^[6]

This guide is for educational purposes. Ratings are the independent opinions of the rating agency, not guarantees, and can change at any time. Verify a carrier's current rating at ambest.com and talk to a licensed broker about your actual exposures.

The Bottom Line

An AM Best rating is an independent opinion of whether an insurer can pay the claims it owes, graded from A++ down to D. B++ and B+ mean Good, not troubled, yet many contracts and lenders still demand A- or better, so a sound carrier can fail your paperwork. Before you bind, pull the exact writing company's grade and outlook at ambest.com and read it against your contract's floor.