Bloomington, Illinois-based State Farm is the top car insurance provider in 29 states. Following behind is Progressive with 10 states and GEICO (owned by Berkshire Hathaway) with nine states plus the District of Columbia. Allstate and MAPFRE are each the top insurers in just one state.

MAPFRE, a Spanish conglomerate, is the top auto insurance company in Massachusetts. This is, in part, thanks to its 2008 purchase of The Commerce Insurance Company, an agency founded in 1972 in Webster, Massachusetts, which was a dominant player in the Bay State's insurance market before the sale and has retained clients since.

Allstate is the top car insurance provider in North Carolina. In 2021, the agency acquired National General, an insurance agency originally founded in 1939 as GMAC Insurance, a part of the General Motors automaking corporation.

It's worth noting, however, that even in Washington D.C., where GEICO (owned by Berkshire Hathaway) has the largest market share of any company in any state, that market share is 38.74%. In other words, nearly 62% of motorists in the district are actually insured by another firm. In California, the state's largest auto insurance company, State Farm, has the smallest market share compared to any top insurer in other states, holding only 12.06% of the market in the Golden State.

Insurers in Ohio wrote $7.0 billion in direct premiums for passenger auto coverage in 2021. Overall, insurers in the state had a loss ratio of 64.1%, compared to about 68% nationwide. These were the top 10 auto insurers by market share in Ohio:
- #1. Progressive Group (17.5% market share)
- #2. State Farm Group (16.8%)
- #3. Allstate Insurance Group (12.0%)
- #4. Berkshire Hathaway Group (8.7%)
- #5. Nationwide Corp Group (5.6%)
- #6. Liberty Mut Group (5.3%)
- #7. Grange Mut Cas Group (4.8%)
- #8. Erie Insurance Group (3.9%)
- #9. United Serv Automobile Assn Group (3.2%)
- #10. American Family Insurance Group (2.7%)

This story features data reporting by Paxtyn Merten, writing by Natalie P. McNeal, and is part of a series utilizing data automation across 51 states.