Guides
The largest workers' comp insurers (2025)
The 25 largest U.S. workers' compensation insurers by 2025 direct premiums written, from NAIC data, and what the ranking means for employers.
Workers' compensation is the one commercial line most employers are required by law to buy, and it is written by an unusual mix of companies: national carriers, regional mutuals, specialists that do little else, and state funds. In 2025 the U.S. market came to $57.71 billion in direct premiums written, according to NAIC market share data, and the 25 groups below wrote 66.5% of it.
The list includes state funds because, in their states, they are often the largest writer. Some are competitive (they sell alongside private carriers and serve as the insurer of last resort); a few are monopolistic, meaning an employer in that state has no private option at all. Our Monopolistic state funds: workers' comp in ND, OH, WA and WY guide explains the difference, and workers' comp requirements by state: who must carry it covers who must buy coverage where.
The top 25
Ranked by 2025 direct premiums written in workers' compensation, U.S. states and territories, by insurance group. Share is of the line's national total ($57.71 billion).
| Rank | Insurer group | 2025 premiums | Share |
|---|---|---|---|
| 1 | The Hartford | $3.73 billion | 6.47% |
| 2 | Travelers | $3.69 billion | 6.40% |
| 3 | AmTrust Financial | $3.52 billion | 6.09% |
| 4 | Zurich North America | $2.79 billion | 4.83% |
| 5 | Chubb | $2.39 billion | 4.14% |
| 6 | Berkshire Hathaway | $1.92 billion | 3.32% |
| 7 | New York State Insurance Fund (NYSIF) | $1.60 billion | 2.77% |
| 8 | Liberty Mutual | $1.58 billion | 2.73% |
| 9 | Old Republic | $1.51 billion | 2.61% |
| 10 | AF Group (Accident Fund) | $1.41 billion | 2.44% |
| 11 | Great American Insurance Group | $1.36 billion | 2.36% |
| 12 | AIG | $1.26 billion | 2.18% |
| 13 | W. R. Berkley | $1.25 billion | 2.17% |
| 14 | CNA | $1.22 billion | 2.11% |
| 15 | Ohio Bureau of Workers' Compensation (monopolistic state fund) | $1.21 billion | 2.10% |
| 16 | ICW Group | $1.15 billion | 1.99% |
| 17 | State Compensation Insurance Fund (State Fund) | $962.0 million | 1.67% |
| 18 | Arch Insurance | $942.6 million | 1.63% |
| 19 | Texas Mutual | $941.9 million | 1.63% |
| 20 | Fairfax Financial | $808.3 million | 1.40% |
| 21 | EMPLOYERS | $747.5 million | 1.30% |
| 22 | Starr Insurance Companies | $662.3 million | 1.15% |
| 23 | Markel | $605.9 million | 1.05% |
| 24 | SAIF Corporation (Oregon state fund) | $580.2 million | 1.01% |
| 25 | Encova Insurance | $568.1 million | 0.98% |
The five largest groups wrote 27.9% of the line, and The Hartford alone wrote 6.5%.
How much of each leader's business this is
Some of the largest writers are specialists for whom workers' compensation is most of what they do; for others it is one line among many. The share below is the line's portion of each group's 2025 premium across the 17 commercial lines in our overall ranking.
| Insurer group | Workers' compensation premiums | Share of its commercial premiums |
|---|---|---|
| The Hartford | $3.73 billion | 26% |
| Travelers | $3.69 billion | 14% |
| AmTrust Financial | $3.52 billion | 56% |
| Zurich North America | $2.79 billion | 19% |
| Chubb | $2.39 billion | 10% |
| Berkshire Hathaway | $1.92 billion | 10% |
| New York State Insurance Fund (NYSIF) | $1.60 billion | 100% |
| Liberty Mutual | $1.58 billion | 8% |
| Old Republic | $1.51 billion | 20% |
| AF Group (Accident Fund) | $1.41 billion | 52% |
Reading the numbers
Direct premiums written are the premiums an insurer booked in the year for policies it issued, before it passed any of the risk to reinsurers. They are the cleanest measure of who sells the most workers' compensation coverage, but they move with price as well as volume: in a year of steep rate increases a carrier can climb the table without insuring a single extra business, and a carrier that shrinks a troubled book on purpose will fall. They also say nothing about profit. NAIC publishes loss ratios beside the premiums, and a large writer with a poor loss ratio may be the one raising rates or tightening appetite next year. Finally, group totals hide brands. The policy you buy is issued by one company inside the group, often under a name you will not see in this table; the how to judge a business insurance company guide explains how to check the company actually named on your quote.
What the ranking means for a buyer
Size alone tells you little about whether a carrier fits your business. Comp is priced from your payroll, your class codes and your experience mod, and carriers differ more in appetite than in price: one writes restaurants and offices online in minutes, another wants contractors with safety programs, a third takes only large accounts on a large-deductible basis. What the national carriers bring is multistate capability (one policy covering employees in many states) and in-house nurse case management and return-to-work programs; what specialists and state funds bring is focus.
If your business is small, start with an agent who can quote several of these markets at once, and check your state's own rules first with workers' comp and benefits requirements by state.
Two cautions when reading the table. First, a state fund's volume is concentrated in one state, so its rank says nothing about its availability elsewhere. Second, premium volume reflects payroll and price as much as the number of employers insured: a carrier with a book of large construction accounts can outrank one that insures many more small offices. A carrier's results matter more than its size for long-tail claims like comp, so read its financial strength rating on the profile.
Questions to ask before you choose a carrier
- Does the carrier write my class codes in every state where I have employees, or will I need a second policy (or a monopolistic state fund policy plus stop gap coverage)?
- How are claims handled: an in-house adjuster or a third-party administrator, and is there 24/7 nurse triage for injured workers?
- What return-to-work and loss control support comes with the policy, and is it included in the premium?
- Is the policy guaranteed cost, or a dividend, retrospective or large-deductible plan, and what collateral would that require?
- How will the premium audit be done, and how is payroll for uninsured subcontractors treated?
How this list was built
The figures are direct premiums written in calendar year 2025 for NAIC's workers' compensation line, for business in the 50 states, D.C. and U.S. territories, from the NAIC's 2025 Market Share Reports for Property/Casualty Groups and Companies (published August 2026). NAIC reports by insurance group, combining affiliated companies under common ownership as filed with the NAIC in August 2025, so a group may sell under several brand names, and ownership changes since then are not reflected. Direct premiums are what the companies wrote before reinsurance; they measure size, not profitability, service or financial strength. Where a group has a profile on this site its name links to it, with its ratings, contacts and history.
For the overall picture across all commercial lines, see The 100 largest U.S. business insurance companies.
Key takeaways
- U.S. workers' compensation direct premiums came to $57.71 billion in 2025 (NAIC).
- The 25 largest groups wrote 66.5% of the line; The Hartford was the largest.
- Size measures premium volume, not price, appetite or claims service; check ratings and fit on each profile.
- Groups combine several companies and brands, so the company on your policy may carry a different name.