Largest Workers’ Compensation Insurers in the U.S.: Top 100 by Direct Premiums Written — NAIC 2025 Report
U.S. Workers’ Compensation Market Leaders by Premium Volume
Hartford Fire & Casualty Group ranks first with $3.734 billion in direct premiums written, followed by Travelers Group at $3.692 billion and AmTrust Financial Services Group at $3.517 billion.
This 2026 snapshot uses the NAIC 2025 Property/Casualty Market Share Report, published August 2026, for the States and U.S. Territories aggregation. The ranking covers the first 100 of the 125 published workers’ compensation groups, companies and state funds. Raw source values are reported in U.S. dollar thousands and are displayed here in millions or billions. Higher direct premiums written rank higher.
The ranking contains 100 official published NAIC values. Most observations use 2025 underlying data. Four state-fund observations use prior-year 2024 data incorporated by NAIC into the 2025 report; those rows are identified individually.
Hartford Fire & Casualty Group ranks first by direct premiums written.
Society Insurance, A Mutual Co is rank 100 in this Top 100.
Official NAIC cumulative market share at rank 100.
NAIC industry total for the workers’ compensation table.
What this workers’ compensation ranking measures
The metric is workers’ compensation direct premiums written for NAIC annual-statement line 16. Direct written premium represents premium written directly by an insurer before adjustments for premiums ceded to reinsurers. Related insurance companies may be aggregated into groups based on ownership, while individual companies and state funds can also appear separately.
In this ranking, “largest” means largest by workers’ compensation direct premiums written. It does not mean largest by assets, policy count, covered workers, profitability or claims volume.
The geographic scope is the NAIC States and U.S. Territories aggregation. It does not use the separate aggregation that also adds Canada and Aggregate Other Alien business.
Top 10 workers’ compensation writers by direct premiums written
The ten largest entries account for an official cumulative 41.80% of workers’ compensation direct premiums written in the NAIC States and U.S. Territories table. Five entries exceed $2 billion in direct premiums written.
Top 10 by direct premiums written — NAIC 2025 report
| Rank | Entity | Direct premiums written | Source / method note |
|---|---|---|---|
| 1 | Hartford Fire & Casualty Group | $3.734B | Official NAIC value · underlying data year 2025. |
| 2 | Travelers Group | $3.692B | Official NAIC value · underlying data year 2025. |
| 3 | AmTrust Financial Services Group | $3.517B | Official NAIC value · underlying data year 2025. |
| 4 | Zurich Insurance Group | $2.786B | Official NAIC value · underlying data year 2025. |
| 5 | Chubb Ltd Group | $2.387B | Official NAIC value · underlying data year 2025. |
| 6 | Berkshire Hathaway Group | $1.919B | Official NAIC value · underlying data year 2025. |
| 7 | State Insurance Fund Workers' Compensation | $1.600B | Official NAIC value · underlying data year 2025. |
| 8 | Liberty Mutual Group | $1.578B | Official NAIC value · underlying data year 2025. |
| 9 | Old Republic Group | $1.505B | Official NAIC value · underlying data year 2025. |
| 10 | BCBS of Michigan Group | $1.411B | Official NAIC value · underlying data year 2025. |
Raw NAIC values are reported in $000. Display labels are converted to millions or billions only for readability; ranking is based on unrounded source values.
Chart: Top 20 workers’ compensation writers
The chart uses the same direct-premium values as the ranking table. Hartford and Travelers are close at the top, while official cumulative market share reaches 61.06% at rank 20.
Methodology
The ranking uses the NAIC 2025 Property/Casualty Market Share Report, published August 2026, line 16, Workers’ Compensation, for the States and U.S. Territories aggregation. All ranks and premium values come from the NAIC report.
Metric and direction
Metric: workers’ compensation direct premiums written. Source unit: U.S. dollars in thousands ($000). Entries are sorted from highest to lowest unrounded premium value.
Report year and underlying years
The ranking is drawn from the NAIC 2025 report. Most observations use 2025 underlying data, while four included state-fund observations use prior-year 2024 data incorporated by NAIC into the 2025 table.
Coverage
NAIC publishes the top 125 countrywide groups and companies for this line. This page includes exactly ranks 1–100 from the States and U.S. Territories table.
Group treatment
Related insurance companies may be aggregated into groups based on ownership. The official table therefore contains a mix of insurance groups, individual companies and state funds.
State-fund treatment
Ohio Bureau of Workers’ Compensation, Workers’ Safety & Compensation Division of Wyoming, Workforce Safety & Insurance of North Dakota and South Carolina State Accident Fund use prior-year 2024 underlying premium data incorporated into the NAIC 2025 report.
Missing and excluded values
Washington State Department of Labor & Industries data were not available for 2025, so no Washington state-fund value is estimated. Excess workers’ compensation is reported separately by NAIC under line 17.3 and is not combined with line 16.
Positive-premium reporting caveat: NAIC displays entities with positive written premium in the market-share report. Negative written-premium amounts are not shown as separate ranking rows, but they remain included in industry total calculations. Official cumulative market shares should therefore be read from the NAIC totals rather than reconstructed only from the displayed positive-premium rows.
Display conversion: source $000 ÷ 1,000 = displayed $ millions; source $000 ÷ 1,000,000 = displayed $ billions. Conversion affects display only and does not change the ranking.
Market share: writer direct premiums written ÷ industry direct premiums written × 100.
What this metric does not measure: profitability, combined ratio, loss ratio, claims service, policy count, covered payroll, number of covered workers, self-insured employer exposure, financial strength or overall insurer quality.
Rounding: ranks are based on the unrounded NAIC source values. Displayed values are rounded only after rank order is fixed.
Main ranking: Top 100 U.S. workers’ compensation writers
Use the controls to search the Top 100, filter by source or status, change sort order, or switch between the Top 10, Top 20 and full ranking.
Top 100 by direct premiums written — NAIC 2025 report, States and U.S. Territories
| Rank | Entity | Direct premiums written | Source / method note |
|---|---|---|---|
| 1 | Hartford Fire & Casualty Group | $3.734B | Official NAIC value · underlying data year 2025. |
| 2 | Travelers Group | $3.692B | Official NAIC value · underlying data year 2025. |
| 3 | AmTrust Financial Services Group | $3.517B | Official NAIC value · underlying data year 2025. |
| 4 | Zurich Insurance Group | $2.786B | Official NAIC value · underlying data year 2025. |
| 5 | Chubb Ltd Group | $2.387B | Official NAIC value · underlying data year 2025. |
| 6 | Berkshire Hathaway Group | $1.919B | Official NAIC value · underlying data year 2025. |
| 7 | State Insurance Fund Workers' Compensation | $1.600B | Official NAIC value · underlying data year 2025. |
| 8 | Liberty Mutual Group | $1.578B | Official NAIC value · underlying data year 2025. |
| 9 | Old Republic Group | $1.505B | Official NAIC value · underlying data year 2025. |
| 10 | BCBS of Michigan Group | $1.411B | Official NAIC value · underlying data year 2025. |
| 11 | American Financial Group | $1.365B | Official NAIC value · underlying data year 2025. |
| 12 | American International Group | $1.260B | Official NAIC value · underlying data year 2025. |
| 13 | W. R. Berkley Corp Group | $1.254B | Official NAIC value · underlying data year 2025. |
| 14 | CNA Insurance Group | $1.217B | Official NAIC value · underlying data year 2025. |
| 15 | Ohio Bureau of Workers' Compensation | $1.211B | Official NAIC value · underlying state-fund data year 2024 · incorporated into the NAIC 2025 report. |
| 16 | ICW Group Assets Inc Group | $1.149B | Official NAIC value · underlying data year 2025. |
| 17 | State Compensation Insurance Fund | $962.0M | Official NAIC value · underlying data year 2025. |
| 18 | Arch Insurance Group | $942.6M | Official NAIC value · underlying data year 2025. |
| 19 | Texas Mutual Group | $941.9M | Official NAIC value · underlying data year 2025. |
| 20 | Fairfax Financial Group | $808.3M | Official NAIC value · underlying data year 2025. |
| 21 | Employers Holdings Group | $747.5M | Official NAIC value · underlying data year 2025. |
| 22 | Starr Group | $662.3M | Official NAIC value · underlying data year 2025. |
| 23 | Markel Group | $605.9M | Official NAIC value · underlying data year 2025. |
| 24 | SAIF Corp | $580.2M | Official NAIC value · underlying data year 2025. |
| 25 | Encova Mutual Insurance Group | $568.1M | Official NAIC value · underlying data year 2025. |
| 26 | AXA Insurance Group | $542.1M | Official NAIC value · underlying data year 2025. |
| 27 | Pinnacol Assurance | $529.1M | Official NAIC value · underlying data year 2025. |
| 28 | CopperPoint Group | $509.9M | Official NAIC value · underlying data year 2025. |
| 29 | Nationwide Corp Group | $504.4M | Official NAIC value · underlying data year 2025. |
| 30 | PIE Group Holdings Inc Group | $477.9M | Official NAIC value · underlying data year 2025. |
| 31 | New Jersey Manufacturers Group | $474.1M | Official NAIC value · underlying data year 2025. |
| 32 | Sentry Insurance Group | $470.1M | Official NAIC value · underlying data year 2025. |
| 33 | The Hanover Insurance Group | $447.8M | Official NAIC value · underlying data year 2025. |
| 34 | Erie Insurance Group | $444.7M | Official NAIC value · underlying data year 2025. |
| 35 | Maine Employers Mutual Insurance Group | $437.9M | Official NAIC value · underlying data year 2025. |
| 36 | Tokio Marine Holdings Inc Group | $427.5M | Official NAIC value · underlying data year 2025. |
| 37 | QBE Insurance Group | $405.0M | Official NAIC value · underlying data year 2025. |
| 38 | Federated Mutual Group | $390.8M | Official NAIC value · underlying data year 2025. |
| 39 | WCF Insurance Co Group | $387.3M | Official NAIC value · underlying data year 2025. |
| 40 | Selective Insurance Group | $326.0M | Official NAIC value · underlying data year 2025. |
| 41 | Everest Reinsurance Holdings Group | $313.4M | Official NAIC value · underlying data year 2025. |
| 42 | Amerisafe Group | $305.0M | Official NAIC value · underlying data year 2025. |
| 43 | Service Insurance Holdings Group | $304.0M | Official NAIC value · underlying data year 2025. |
| 44 | West Bend Insurance Group | $291.4M | Official NAIC value · underlying data year 2025. |
| 45 | Acuity, A Mutual Insurance Co | $287.0M | Official NAIC value · underlying data year 2025. |
| 46 | Amerisure Companies Group | $286.0M | Official NAIC value · underlying data year 2025. |
| 47 | SFM Group | $269.1M | Official NAIC value · underlying data year 2025. |
| 48 | Missouri Employers Mutual Group | $267.8M | Official NAIC value · underlying data year 2025. |
| 49 | Brookfield Wealth Solutions Group | $262.5M | Official NAIC value · underlying data year 2025. |
| 50 | Sompo Group | $258.5M | Official NAIC value · underlying data year 2025. |
| 51 | Builders Group | $257.0M | Official NAIC value · underlying data year 2025. |
| 52 | Louisiana Workers' Compensation Group | $255.6M | Official NAIC value · underlying data year 2025. |
| 53 | Auto-Owners Group | $255.3M | Official NAIC value · underlying data year 2025. |
| 54 | Group 1001 Insurance Holdings Group | $251.9M | Official NAIC value · underlying data year 2025. |
| 55 | Cincinnati Financial Group | $244.5M | Official NAIC value · underlying data year 2025. |
| 56 | State Farm Group | $239.1M | Official NAIC value · underlying data year 2025. |
| 57 | EMC Insurance Companies Group | $233.9M | Official NAIC value · underlying data year 2025. |
| 58 | ProAssurance Corp Group | $230.4M | Official NAIC value · underlying data year 2025. |
| 59 | Idaho State Insurance Fund | $225.4M | Official NAIC value · underlying data year 2025. |
| 60 | Benchmark Holding Group | $224.1M | Official NAIC value · underlying data year 2025. |
| 61 | Core Specialty Insurance Holdings Group | $207.5M | Official NAIC value · underlying data year 2025. |
| 62 | Workers' Safety & Compensation Division of Wyoming | $206.3M | Official NAIC value · underlying state-fund data year 2024 · incorporated into the NAIC 2025 report. |
| 63 | Workforce Safety & Insurance of North Dakota | $205.0M | Official NAIC value · underlying state-fund data year 2024 · incorporated into the NAIC 2025 report. |
| 64 | Utica Group | $196.7M | Official NAIC value · underlying data year 2025. |
| 65 | Omaha National Group | $190.0M | Official NAIC value · underlying data year 2025. |
| 66 | AIM Mutual Group | $185.3M | Official NAIC value · underlying data year 2025. |
| 67 | RetailFirst Group | $179.8M | Official NAIC value · underlying data year 2025. |
| 68 | Farmers Insurance Group | $178.9M | Official NAIC value · underlying data year 2025. |
| 69 | Chesapeake Employers Insurance Co | $175.1M | Official NAIC value · underlying data year 2025. |
| 70 | Montana State Fund | $172.6M | Official NAIC value · underlying data year 2025. |
| 71 | RAS Dakota Group | $171.1M | Official NAIC value · underlying data year 2025. |
| 72 | CompSource Mutual Insurance Co | $160.6M | Official NAIC value · underlying data year 2025. |
| 73 | FCCI Mutual Insurance Group | $156.8M | Official NAIC value · underlying data year 2025. |
| 74 | Ascot Insurance U.S. Group | $155.7M | Official NAIC value · underlying data year 2025. |
| 75 | Kentucky Employers Mutual Insurance | $136.4M | Official NAIC value · underlying data year 2025. |
| 76 | SUNZ Holdings LLC Group | $131.0M | Official NAIC value · underlying data year 2025. |
| 77 | SECURA Insurance Group | $130.5M | Official NAIC value · underlying data year 2025. |
| 78 | Builders Insurance Group | $126.5M | Official NAIC value · underlying data year 2025. |
| 79 | UPMC Health System Group | $125.9M | Official NAIC value · underlying data year 2025. |
| 80 | LUBA Mutual Group | $118.5M | Official NAIC value · underlying data year 2025. |
| 81 | Hawaii Employers Group | $112.3M | Official NAIC value · underlying data year 2025. |
| 82 | Donegal Group | $111.2M | Official NAIC value · underlying data year 2025. |
| 83 | Western National Mutual Group | $107.2M | Official NAIC value · underlying data year 2025. |
| 84 | Beacon Mutual Group | $105.9M | Official NAIC value · underlying data year 2025. |
| 85 | AU Holding Co Group | $104.9M | Official NAIC value · underlying data year 2025. |
| 86 | Frankenmuth Group | $104.8M | Official NAIC value · underlying data year 2025. |
| 87 | New Mexico Mutual Group | $91.4M | Official NAIC value · underlying data year 2025. |
| 88 | Church Mutual Group | $90.7M | Official NAIC value · underlying data year 2025. |
| 89 | South Carolina State Accident Fund | $90.1M | Official NAIC value · underlying state-fund data year 2024 · incorporated into the NAIC 2025 report. |
| 90 | FFVA Group | $89.2M | Official NAIC value · underlying data year 2025. |
| 91 | United Fire & Casualty Group | $84.8M | Official NAIC value · underlying data year 2025. |
| 92 | MS & AD Insurance Group | $76.1M | Official NAIC value · underlying data year 2025. |
| 93 | State Workers Insurance Fund | $75.4M | Official NAIC value · underlying data year 2025. |
| 94 | Progressive Group | $74.5M | Official NAIC value · underlying data year 2025. |
| 95 | Brotherhood Mutual Insurance Co | $72.0M | Official NAIC value · underlying data year 2025. |
| 96 | Midwest Builders Casualty Group | $70.1M | Official NAIC value · underlying data year 2025. |
| 97 | Normandy Insurance Co | $68.1M | Official NAIC value · underlying data year 2025. |
| 98 | Pekin Insurance Group | $67.5M | Official NAIC value · underlying data year 2025. |
| 99 | Harford Group | $64.3M | Official NAIC value · underlying data year 2025. |
| 100 | Society Insurance, A Mutual Co | $59.6M | Official NAIC value · underlying data year 2025. |
The table includes ranks 1–100 of the 125 entries published by NAIC for Workers’ Compensation, States and U.S. Territories. Industry direct premiums written total $57.714733 billion. Official cumulative market share at rank 100 is 96.11%.
Insights from the Top 100
Key Insight
The Top 10 reach 41.80% cumulative market share in the official NAIC table.
Notable Pattern
Cumulative share reaches 61.06% at rank 20, 83.20% at rank 50 and 96.11% at rank 100.
Source Concentration
All Top 100 ranking values come from the same NAIC market-share table, avoiding cross-source differences in unit, geography and ranking methodology.
Top-End Scale Break
Five entries exceed $2 billion in direct premiums written. Berkshire Hathaway Group ranks sixth at $1.919 billion.
How to interpret the ranking
A higher position means a larger amount of workers’ compensation direct premium written in the NAIC table. It does not by itself indicate better profitability, financial strength, customer service or claims handling.
Four state-fund entries use underlying 2024 observations even though NAIC incorporates them into the 2025 report. They are official published values, but they should not be read as 2025-period observations.
FAQ
Who is the largest workers’ compensation insurer in this ranking?
Hartford Fire & Casualty Group ranks first with $3.734 billion in direct premiums written.
Are these all 2025 premium observations?
No. The ranking comes from the NAIC 2025 Property/Casualty Market Share Report, published in August 2026. Most observations use 2025 underlying data, while four state-fund observations use prior-year 2024 data incorporated into the report.
Are the values officially published?
Yes. Every Top 100 premium value is published directly in the NAIC market-share table. No ranking value is modeled or imputed.
What does direct written premium mean?
It is premium written directly by an insurer before adjustment for premium ceded to reinsurers.
Why does the ranking include groups, companies and state funds?
NAIC can aggregate related insurance companies into groups based on ownership, while individual insurers and state funds can appear separately in the official table.
Which entries use prior-year data?
Ohio Bureau of Workers’ Compensation, Workers’ Safety & Compensation Division of Wyoming, Workforce Safety & Insurance of North Dakota and South Carolina State Accident Fund use underlying 2024 data incorporated into the NAIC 2025 report.
Why is Washington State Fund not included?
NAIC states that Washington State Department of Labor & Industries data were not available for 2025. No replacement estimate is used in this ranking.
Does the ranking include excess workers’ compensation?
No. This ranking uses NAIC line 16 Workers’ Compensation. Excess Workers’ Compensation is reported separately under line 17.3.
Sources
NAIC 2025 Property/Casualty Market Share Report
Primary numeric source for ranks, direct premiums written, cumulative market shares, industry totals and workers’ compensation technical notes.
https://content.naic.org/sites/default/files/publication-msr-pb-property-casualty.pdf
NAIC Glossary of Insurance Terms
Terminology reference for direct written premium and insurance reporting concepts.
NAIC Workers’ Compensation Insurance
Official background on workers’ compensation insurance.
https://content.naic.org/insurance-topics/workers%27-compensation-insurance
