NAIC market share reports: who writes auto insurance in your state

To see which companies write the most car insurance in your state, open the NAIC's annual Property/Casualty Market Share Report and look at the private passenger auto table for your state, which ranks the top ten groups by direct premiums written. Many state insurance departments publish their own version with every company listed. The ranking is by corporate group, not by brand, and a group can contain a dozen legally separate insurance companies, so the first job when reading a list is to find out which companies sit under which group.

The reports measure size, not quality. They are good for answering "who are the big writers here, who is growing, and how did their claims run last year," and poor for answering "who should I buy from." This article explains each column, shows what the data looked like for 2025 in the national report and in two state versions, and lists what the numbers cannot tell you.

What the reports are and where to find them

The NAIC's 2025 Market Share Reports for Property/Casualty Groups and Companies, dated August 2026, take their figures from insurers' annual statements. Direct written premium comes from the Exhibit of Premiums and Losses in the NAIC property/casualty annual statement. The report covers 36 lines of business, shows the top 125 groups and companies countrywide for each line, and the top 10 by state.

Timing matters. The NAIC releases an early look in the spring using filings received to date: its March 2025 release for the 2024 data year said only about 84% of property/casualty companies had reported at that point, and that the full reports would follow in the summer. If you are reading a number from a news story in March or April, it may come from a partial data set.

Three state departments illustrate the state-level versions:

• Ohio posts a 2025 market share report listing the top 15 groups with every company in each group, using NAIC data as of June 23, 2026.
• California has produced a market share report every year since Proposition 103 passed in 1988, according to the preface of its 2025 report, and adds a combined private passenger auto line.
• North Carolina publishes a 2025 private passenger auto file with a row for each company: premiums written and earned, losses paid and incurred, group name and market share.

Other states publish similar documents. Search your state department's site for "market share."

Which line of business to read

Auto insurance is spread across several lines on the annual statement. For personal auto the relevant ones are line 19.1 (private passenger auto no-fault, meaning personal injury protection), line 19.2 (other private passenger auto liability) and line 21.1 (private passenger auto physical damage, meaning collision and comprehensive), as the Ohio report's appendix lists them. California's preface notes that it combines 19.2 and 21.1 for its combined line, since California does not have no-fault coverage.

The NAIC report itself combines no-fault and liability because no-fault data are reported inconsistently across companies and states, so you will see a liability table and a total private passenger auto table. Pick the one that matches your question:

Pay attention to the heading, because "Total All Lines" and "Total Private Passenger Auto" are very different tables.

The columns, one by one

The NAIC's technical notes define the main columns. Here is how to read them.

Direct premiums written (DPW). The premium on policies the insurer issued during the year, before reinsurance. The NAIC takes it from the statement's state page. "Direct" means business written directly, not assumed from other insurers.

Direct premiums earned (DPE). The part of premium that applies to coverage actually provided during the year. A six-month policy written in November is mostly unearned at year end. Earned premium is the fair denominator for a loss ratio, because losses incurred in a year come from coverage given in that year. See earned premium.

Market share. Per the technical notes, a company's or group's direct premiums written divided by total direct premiums written, either countrywide or for the state. It is a share of premium dollars, not of drivers or vehicles. An insurer that sells expensive policies has more share per customer than one selling cheap ones.

Cumulative market share. The running total down the list. It tells you how concentrated a market is. If the top four groups together hold 60% of the premium, the market is more concentrated than if the top four hold 35%. For a fuller discussion see how concentrated the auto insurance market is, nationally and by state.

Loss ratio and loss and cost containment ratio. See the section below.

Rank and codes. Rank is by premium. The group code is the NAIC's numerical identifier, useful when a name changes.

The NAIC also notes that only companies with positive written premium appear in the tables; companies with negative premium are left off the list, but their amounts are included in the totals.

Group versus company: the distinction that matters most

The NAIC explains that an insurance group is a set of companies related by ownership, and that showing data by group lets the report more accurately reflect how many distinct entities compete. An index at the back of the report lists the individual companies in each group as a snapshot of group structures as of when the report was generated, because insurers merge, rename and buy and sell companies.

This matters for three reasons.

1. Brands are not groups. GEICO sells through companies in the Berkshire Hathaway group. An insurer whose name you know may appear under a different name. who owns whom: car insurance brands and their parent companies maps the common ones.
2. One group can hold many companies. Ohio's company-level page for 2025 private passenger auto shows State Farm's group with State Farm Mutual Automobile Insurance Company writing 20.1% of Ohio's premium and State Farm Fire and Casualty another 1.5%. The Allstate group in the same table spans about 17 companies, from Allstate Fire and Casualty to several Integon and Esurance entities.
3. Rankings can flip depending on the view. Ranked by company, a well-known single-company writer can top the list; ranked by group, a parent with many subsidiaries can overtake it.

Example: North Carolina, 2025

North Carolina's 2025 file covers lines 19.1, 19.2 and 21.1 and totals about $9.97 billion in direct premium written. State Farm Mutual Automobile Insurance Company is the largest single company, with 14.6% of the premium. But if you add up company rows by the group name column (our arithmetic), the Allstate group, which includes the Integon companies as well as Allstate's own, comes to about 20.4%, ahead of Progressive's group at about 15.5%, State Farm's group at 14.6% and the Berkshire Hathaway group (GEICO) at about 10.4%. North Carolina Farm Bureau, a regional mutual, holds about 10.4% in its home state, though it is a tiny fraction of the national market. (North Carolina has an unusual rate-setting system; see North Carolina's rate bureau and Reinsurance Facility: a system apart.)

The lesson: the same data supports "State Farm is the biggest company in North Carolina" and "Allstate is the biggest group." Both are true.

The national picture, 2025

In the NAIC's countrywide table for total private passenger auto in the 2025 report, the leading groups by direct premiums written were State Farm (18.62% of premium and $69.16 billion), Progressive (18.58%, $69.01 billion), Berkshire Hathaway (11.54%) and Allstate (10.14%), together holding 58.87%. The industry's direct loss ratio for the line was about 61.5%.

State lists look different. In Ohio, the 2025 report shows State Farm's group at 21.8% of the state's private passenger auto premium, Progressive at 21.5%, Allstate at 11.6% and Berkshire Hathaway at 6.5%, out of $9.26 billion. Your own state's top ten will not match the country's.

Reading the loss ratio columns

Most tables include two ratios, defined in the NAIC's technical notes:

• Loss ratio = direct losses incurred divided by direct premiums earned, times 100.
• Loss and cost containment ratio = direct losses incurred plus direct defense and cost containment expenses incurred, divided by direct premiums earned, times 100.

For the 2025 national table, the loss ratios of the four largest groups were 65.49% for State Farm, 59.07% for Progressive, 67.16% for Berkshire Hathaway and 55.64% for Allstate. In North Carolina's file, the same calculation (our arithmetic from the direct losses incurred and direct premiums earned columns) gives about 61% for State Farm and for Progressive, about 56% for the Allstate group and about 66% for Berkshire Hathaway.

A worked example. Say a group has $2.0 billion of direct premiums earned in a state and $1.2 billion of direct losses incurred that year. The loss ratio is 1.2 divided by 2.0, or 60%. The remaining 40 cents of each premium dollar had to cover agent commissions, advertising, salaries, adjusting costs, taxes and profit, and defense costs are in the second ratio, not the first. These numbers are hypothetical.

The NAIC is explicit about limits. Its report says the ratios "reflect a simple calendar-year result" and should not be considered measures of overall profitability, since expenses and investment income are not included. A few cautions follow:

• A low loss ratio can mean careful underwriting, high prices relative to risk, or a mild year. It does not mean policyholders got a better deal.
• A high loss ratio can mean a bad year, rates that lag costs, or growth into riskier business. It can also be a signal of rate increases to come.
• Ratios from small writers swing wildly from one year to the next. Treat a single year at a small insurer as noise. The same small-numbers problem affects complaint ratios (see the small-numbers problem in insurer complaint ratios).
• Ratios are not comparable across states with different coverage mixes, such as no-fault states with personal injury protection.

For profitability itself, the NAIC publishes separate reports that cover expenses and multiple years; see Profitability by line and state: what NAIC data says about margins.

Residual market share

Some drivers cannot find coverage in the regular market and are placed through state assigned-risk plans or similar mechanisms. See assigned risk plan and residual market. In the NAIC market share tables, such business is reported by the insurer that writes or is assigned it, like any other premium. In the NAIC and state tables we reviewed, we did not find a separate column that labels residual-market premium, so do not assume the market share figure splits voluntary and residual business. The workers' compensation section of the NAIC report does add state fund and residual market data reported directly to the NAIC, but that is a different line. If a state's residual market is large, look for a separate residual market report from the state department or the plan administrator.

A step-by-step way to use the reports

1. Choose the year. The NAIC full report for the 2025 data year is dated August 2026. Early-year releases use partial data.
2. Pick the line. For most drivers, total private passenger auto. If you care about injury coverage only, use liability.
3. Go to your state. In the NAIC report, find the "By State By Group" section. For fuller detail on every company, use your state department's version.
4. Read the group, then the companies. Check which companies sit under each group. Note the company that actually issues your policy; your policy documents name it.
5. Compare shares, not just ranks. A group in fifth place with 3% is in a different position than one in fifth place with 8%.
6. Look at the loss ratio next to the share. Rapid growth with a rising loss ratio can be a warning sign. The NAIC itself says that rapid share growth can signal an insurer growing too fast, while sharp declines can mean it is shrinking its exposure or facing trouble.
7. Cross-check elsewhere. Use financial strength ratings (AM Best financial strength ratings explained), the NAIC complaint index (The NAIC complaint index: how to look up an insurer) and your own quotes.

What the reports cannot tell you

• Price. A big writer is not necessarily cheaper. Premium share reflects customers and prices together. Use quotes (and a tool such as the compare auto insurers side by side) for price.
• Service. Market share says nothing about claims handling or customer satisfaction.
• Where you can buy. A group may be large in your state but not accept your risk profile, or not sell in your ZIP code.
• How a group sells. Large shares are built through different channels, including captive agent networks, independent agents and direct sales, and through different corporate forms such as the mutual insurance company.
• Stability of the list. Mergers, acquisitions and renamed companies change group membership. The NAIC index is a snapshot.

Common questions

Why does my insurer not appear in the top ten for my state?

The state table shows only the ten largest groups. Smaller or regional insurers are still licensed and may be a good fit. State department versions with full company lists, such as Ohio's and North Carolina's, show the rest.

Is the market share the same as the share of drivers?

No. It is a share of premium dollars. An insurer that serves higher-priced risks, such as young drivers, will show a bigger share of premium than of vehicles.

How can the same company show different numbers on different reports?

Reports may cover different lines (liability only versus total), different years, or different jurisdictions (states only versus states plus Canada and other alien business). The NAIC report itself offers both countrywide views. Group membership and data updates also change.

Do these reports show who is raising rates?

Not directly. They show premium volume and loss experience, which are inputs to rate decisions. For rate filings and approvals see how car insurance rate approval works.

Key takeaways

• The NAIC market share reports rank groups by direct premiums written, with the top 10 by state and the top 125 countrywide for each line; state insurance departments publish versions with every company listed.
• Always separate group from company: one group can include more than a dozen legal entities, and in North Carolina the largest company and the largest group were different.
• In the NAIC's 2025 countrywide private passenger auto table, State Farm, Progressive, Berkshire Hathaway and Allstate together held 58.87% of premium.
• Loss ratios are calendar-year, direct-basis results that exclude expenses and investment income, so they do not show profit, price or value to a customer.
• Use the reports to see who writes the business in your state, then check ratings, complaints and quotes before choosing.