Company lists · Data refreshed September 2026
Top 25 Casualty insurance underwriting companies based in the United States
RevenueBase identified 874 casualty insurance underwriting companies headquartered in the United States as of September 2026 and tracks 154,570 professional contacts across them, including 72,079 with verified work emails. New York is the largest hub.
This list covers casualty insurance underwriting companies headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 15, 2026.
Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.
The 25 largest casualty insurance underwriting companies based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 32,682 contacts → | ||||
Partial evidence “Travelers provides insurance coverage to protect the things that are important to you – your home, your car, your valuables and your business.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 2 | 30,330 contacts → | ||||
Indirect evidence “At Liberty Mutual, we believe progress happens when people feel secure.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 3 | 5,132 contacts → | ||||
Partial evidence “Rooted in our commitment to be with you, every step, The Hanover Insurance Group, Inc.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 4 | 4,926 contacts → | ||||
Partial evidence “Amwins is the largest wholesale distributor of specialty insurance products and services in the U.S.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 5 | 4,734 contacts → | ||||
Strong evidence “AmTrust Financial Services, Inc, through its subsidiaries, operates as a multinational property and casualty insurance company.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 6 | 3,963 contacts → | ||||
Partial evidence “Sentry Insurance got its start in 1904, when members of the Wisconsin Retail Hardware Association formed their own insurance company.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 7 | 3,411 contacts → | ||||
Strong evidence “Everest Group, Ltd.(“Everest”) is a global underwriting leader providing best-in-class property, casualty, and specialty reinsurance and insurance solutions that address…” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 8 | 3,186 contacts → | ||||
Indirect evidence “At Mercury, we have been guided by our purpose to help people reduce risk and overcome unexpected events for more than 60 years.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 9 | 3,021 contacts → | ||||
Indirect evidence “When it comes to protecting what matters most in business and everyday life, at McGriff we believe our clients should never settle for less than the best.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 10 | 2,955 contacts → | ||||
Partial evidence “RT Specialty is a leading wholesale distributor of specialty insurance products and services and the wholesale broking specialty for Ryan Specialty.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 11 | 2,704 contacts → | ||||
Partial evidence “Arch Insurance Group Inc, a division of Arch Capital Group Ltd.(ACGL), is a market-leading specialty insurer.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 12 | 2,105 contacts → | ||||
Strong evidence “Crum & Forster (C&F) provides market leading property & casualty, accident & health, specialty and standard commercial lines insurance solutions.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 13 | 2,006 contacts → | ||||
Indirect evidence “Tokio Marine HCC focuses on what matters most; our people.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 14 | 1,799 contacts → | ||||
Partial evidence “Berkshire Hathaway Specialty Insurance is an organization committed to providing long-term risk solutions and claims care to our customers backed by the financial strength of…” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 15 | 1,386 contacts → | ||||
Partial evidence “RLI is a U.S-based specialty insurer that serves niche property, casualty and surety markets.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 16 | 1,314 contacts → | ||||
Strong evidence “We aspire to be the very best insurance company at underwriting insurance products for our customers.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 17 | 1,266 contacts → | ||||
Strong evidence “ICW Group Insurance Companies is a top-tier, national, multi-line Property & Casualty insurance company, providing comprehensive coverage to safeguard our customers’ world.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 18 | 1,262 contacts → | ||||
Indirect evidence “ESIS®, Inc.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 19 | 1,145 contacts → | ||||
Strong evidence “CapSpecialty® is a leading provider of specialty insurance for small to mid-sized businesses in the U.S, offering casualty, professional liability, surety and fidelity products in…” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 20 | 1,097 contacts → | ||||
Strong evidence “Underwriting solutions at Verisk is a leading provider of advanced tools and analytics for the property/casualty and life insurance industries.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 21 | 1,079 contacts → | ||||
Strong evidence “Ryan Specialty (NYSE: RYAN) is an international specialty insurance firm that provides distribution, underwriting, product development, administration and risk management services…” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 22 | 1,036 contacts → | ||||
Strong evidence “FCCI Insurance Group provides commercial property and casualty insurance.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 23 | 1,008 contacts → | ||||
Strong evidence “Founded in 1946 as United Fire & Casualty Company, UFG Insurance (Nasdaq: UFCS) is engaged in the business of writing property and casualty insurance through its insurance company…” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 24 | 851 contacts → | ||||
Strong evidence “Argo Group is a U.S-focused underwriter of specialty insurance products in the property and casualty market.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 25 | 843 contacts → | ||||
Strong evidence “Rated A+ Superior by AM Best (as of 8/13/25), Berkshire Hathaway GUARD Insurance Companies provides Property & Casualty insurance including Excess & Surplus lines.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
RevenueBase Smart Search
RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: casualty insurance underwriting companies. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.
- Strong evidence
- The company's own public description of its business names casualty insurance underwriting companies.
- Partial evidence
- Its own public description names part of casualty insurance underwriting companies, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name casualty insurance underwriting companies. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.
RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.
Showing 25 of 874 casualty insurance underwriting companies based in the United States
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Casualty insurance underwriting companies based in the United States at a glance
As of Sep 15, 2026Companies by employee count
Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 874 companies.
How this list was built
Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among casualty insurance underwriting companies, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.
- Source
- The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
- What qualifies
- Companies headquartered in the United States whose own description of what they do matches “casualty insurance underwriting companies”. Matching reads each company's description, not its industry code or its name.
- RevenueBase Smart Search
- RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names casualty insurance underwriting companies), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
- What we exclude
- Companies whose own description does not clearly place them among casualty insurance underwriting companies, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
- Match quality
- In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
- Ranking
- Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
- Verification
- Every listed company carries at least one verified work email, 72,079 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
- Refresh
- This page's figures were pulled from the company graph on September 15, 2026. Lists refresh periodically as the graph is re-checked.
- Corrections
- Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.
Casualty insurance underwriting companies by metro
- Casualty insurance underwriting companies in New York27
Frequently asked
What is RevenueBase Smart Search?
RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names casualty insurance underwriting companies, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.
How many casualty insurance underwriting companies are there based in the United States?
RevenueBase identified 874 casualty insurance underwriting companies headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.
What is the largest company on this list?
Travelers, headquartered in New York, tops this list with the largest team on record.
Which city has the most casualty insurance underwriting companies?
New York leads with 27 headquartered companies, followed by Houston (17) and Chicago (14).
How do I get contact information for these companies?
A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 72,079 verified decision-maker contacts tracked across these 874 companies.
How current is this list?
The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 15, 2026.
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About this data
RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.
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