Largest Auto Insurance Companies in the US, Ranked by Market Share
The biggest US auto insurance companies ranked by NAIC-reported market share and written premium -- the actual size of each carrier's book of business, not a marketing claim.
Research period:
What this ranks: NAIC-reported market share, the size of each carrier's written auto premium, not price, service quality, complaint record, or which insurer is right for you. See PlainInsurer's complaint and denial-rate rankings for those dimensions, and compare quotes directly before you buy.
Research question
Among the 25 largest US auto insurers by NAIC-reported market share, what share of total written premium is concentrated in the top 10, and what is the absolute gap between the largest and the tenth-largest insurer?
Methodology
This ranking reflects the 10 largest auto insurers by market share, drawn from the National Association of Insurance Commissioners' NAIC Market Share Annual Report. Every figure updates automatically as new NAIC filings are processed; nothing on this page is hand-entered.
Coverage and exclusions: NAIC occasionally suppresses values for confidentiality, small sample size, or quality control, and suppressed rows are excluded from this ranking rather than shown as zero. If NAIC later revises a figure, the revised value replaces the old one automatically the next time the portal's data is refreshed.
Data provenance: NAIC publishes the Market Share Annual Report on its own release schedule. We pull each release as it becomes available and normalize it into our database; a later release simply supersedes the one before it, so readers never see a mix of old and new figures on the same page.
Comparability across years: when NAIC revises its release schedule, definitions, or coverage, we note the affected years on the methodology page so readers can compare like-with-like rather than across a changed measurement.
Editorial governance: PlainInsurer publishes its editorial policy and corrections process. If an insurer disputes a figure attributed to it, the correction is checked against the official NAIC record before any change is made.
Every number on this page can be traced back to its NAIC source by following the entity links and the citation below, so independent verification never requires anything beyond the original public source.
See the methodology page for the complete ETL pipeline, source vintage, and column lineage.
Largest auto insurers by market share
Live data: reflects the current NAIC Market Share Annual Report snapshot
The ranked top 10
Every row below reflects the current 10-company dataset. Reload the page after new NAIC data is processed to see the latest values.
| # | Rank | Auto insurer | Insurance group | Market share % | Written premium ($M) |
|---|---|---|---|---|---|
| 1 | 1 | State Farm Group | State Farm Mutual Automobile Insurance Co. | 17.1% | 47,910 |
| 2 | 2 | Progressive Group | Progressive Corporation | 14.3% | 39,990 |
| 3 | 3 | Allstate Insurance Group | Allstate Insurance Company | 10.7% | 30,070 |
| 4 | 4 | GEICO (Berkshire Hathaway) | Government Employees Insurance Co. (GEICO) | 9.8% | 27,340 |
| 5 | 5 | USAA Group | United Services Automobile Association | 6.1% | 17,070 |
| 6 | 6 | Farmers Insurance Group | Farmers Group, Inc. | 4.5% | 12,540 |
| 7 | 7 | Liberty Mutual Group | Liberty Mutual Insurance Companies | 4.2% | 11,890 |
| 8 | 8 | Travelers Group | The Travelers Companies, Inc. | 2.3% | 6,310 |
| 9 | 9 | American Family Insurance Group | American Family Mutual Insurance Co. | 2.1% | 6,030 |
| 10 | 10 | Nationwide Group | Nationwide Mutual Insurance Company | 2.1% | 5,920 |
Source: National Association of Insurance Commissioners, NAIC Market Share Annual Report. Values reflect the current dataset, refreshed as new NAIC filings are processed. National Association of Insurance Commissioners, NAIC Market Share Annual Report. Values reflect the current dataset, refreshed as new NAIC filings are processed.
Findings
Top entity in the ranking
The top-ranked record in this dataset is State Farm Group, with a market share of 17.1%. The full top-10 set is rendered in the table above. When the source agency publishes a revision, the ranking and the prose around it update automatically.
Distribution shape
The gap between the top-ranked record (17.1%) and the 10th-ranked record (2.1%) characterizes how concentrated the top of the distribution is. Where the top value is many multiples of the median value of the visible set, the population is highly concentrated, a small number of entities accumulate the bulk of the measured quantity. Where the top and bottom of the visible set are close together, the distribution is relatively flat across the top end. The full distribution beyond this top-10 cut is summarized in the aggregate context section below and explored in the linked entity profiles.
Aggregate context
Across the full population behind this ranking, here are the summary statistics: how many records exist in total, the sum of the ranking metric across all qualifying records, and the mean per-record value. The methodology page documents the exact filter applied (records with null or zero values on the ranking metric are excluded). This aggregate row is computed from the same dataset that powers the ranking above.
Source provenance
The records in this ranking originate from National Association of Insurance Commissioners, specifically the NAIC Market Share Annual Report. Plaininsurer ingests the source vintage published by the agency and keeps this page current, there is no static export carrying stale numbers, and a newly published dataset is reflected here within hours. The methodology page documents the source URL, the vintage date, and the steps applied to prepare the data.
Why this ranking matters
Rankings like this one let a reader scan a population quickly and identify outliers, concentrations, and patterns that warrant deeper investigation. The detail pages linked from each entity in the table above give the full per-entity context: time-series history where available, related metrics from adjacent tables, and links onward to the underlying source records. The methodology page explains how an entity earns inclusion in the dataset and how the ranking column is computed at the source.
What this analysis cannot tell us
NAIC market-share figures aggregate written premium across all auto-insurance lines (private passenger auto, commercial auto, both liability and physical damage). Companies belonging to the same insurance group may file under separate NAIC company codes, which can split apparent market share across multiple rows; the group_name column shows the parent group where the relationship is recorded. Market share is computed from NAIC Annual Statement filings for the displayed data year and lags current market conditions. Mutual companies, fraternal benefit societies, and reciprocal exchanges follow different reporting practices than stock companies, but all are included in the NAIC consolidated rollup. State-level rate adequacy, profitability, and policy availability are not captured by national market share; consumers in any given state should consult their state insurance commissioner for state-specific guidance.
Secondary cut from the same source
Top 10 auto insurers by written premium (millions of dollars)
Sources
- NAIC Annual Statement Database - https://content.naic.org
- NAIC Market Share Reports - https://content.naic.org
- NAIC Auto Insurance Database Reports - https://content.naic.org/sites/default/files/aut-db_1.pdf