Company lists · Data refreshed September 2026

Top 25 Casualty insurance underwriting companies based in the United States

RevenueBase identified 874 company matches for casualty insurance underwriting companies associated with 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 company matches for casualty insurance underwriting companies associated with the United States, found by RevenueBase SmartSearch using the meaning of business descriptions in its company graph at Exact. Ranked by professionals tracked, largest first. Rows show recorded descriptions where available, Exact search membership and the snapshot date. Data refreshed September 15, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase SmartSearch, 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.

How to read this list RevenueBase SmartSearch · Exact Recorded Sep 15, 2026 How this list was built
874Companies
154,570Contacts tracked
72,079Verified emails
Explore this list → Free signup · no credit card · 500 free credits

The 25 largest casualty insurance underwriting companies based in the United States

Ranked by team size
Top 25 of 874 company matches for casualty insurance underwriting companies based in the United States, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Sep 15, 2026. The RevenueBase SmartSearch column shows Exact match membership in this saved search. Click a contact count to view that company's people. Totals use company locations recorded by RevenueBase; the displayed preview is a smaller selection.
#CompanyRevenueBase SmartSearchHeadquartersEmployeesContacts
1Exact matchNew York, NY, United StatesHQ recorded Sep 15, 202610001+32,682 contacts →

Exact match

“Travelers provides insurance coverage to protect the things that are important to you – your home, your car, your valuables and your business.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
2Exact matchBoston, MA, United StatesHQ recorded Sep 15, 202610001+30,330 contacts →

Exact match

“At Liberty Mutual, we believe progress happens when people feel secure.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
3Exact matchWorcester, MA, United StatesHQ recorded Sep 15, 20265,001-10,0005,132 contacts →

Exact match

“Rooted in our commitment to be with you, every step, The Hanover Insurance Group, Inc.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
4Exact matchCharlotte, NC, United StatesHQ recorded Sep 15, 20265,001-10,0004,926 contacts →

Exact match

“Amwins is the largest wholesale distributor of specialty insurance products and services in the U.S.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
5Exact matchNew York, NY, United StatesHQ recorded Sep 15, 20265,001-10,0004,734 contacts →

Exact match

“AmTrust Financial Services, Inc, through its subsidiaries, operates as a multinational property and casualty insurance company.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
6Exact matchStevens Point, WI, United StatesHQ recorded Sep 15, 20265,001-10,0003,963 contacts →

Exact match

“Sentry Insurance got its start in 1904, when members of the Wisconsin Retail Hardware Association formed their own insurance company.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
7Exact matchWarren, NJ, United StatesHQ recorded Sep 15, 20261,001-5,0003,411 contacts →

Exact match

“Everest Group, Ltd.(“Everest”) is a global underwriting leader providing best-in-class property, casualty, and specialty reinsurance and insurance solutions that address…”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
8Exact matchBrea, CA, United StatesHQ recorded Sep 15, 20265,001-10,0003,186 contacts →

Exact match

“At Mercury, we have been guided by our purpose to help people reduce risk and overcome unexpected events for more than 60 years.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
9Exact matchCharlotte, NC, United StatesHQ recorded Sep 15, 20261,001-5,0003,021 contacts →

Exact match

“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.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
10Exact matchChicago, IL, United StatesHQ recorded Sep 15, 20261,001-5,0002,955 contacts →

Exact match

“RT Specialty is a leading wholesale distributor of specialty insurance products and services and the wholesale broking specialty for Ryan Specialty.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
11Exact matchJersey City, NJ, United StatesHQ recorded Sep 15, 20261,001-5,0002,704 contacts →

Exact match

“Arch Insurance Group Inc, a division of Arch Capital Group Ltd.(ACGL), is a market-leading specialty insurer.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
12Exact matchMorristown, NJ, United StatesHQ recorded Sep 15, 20261,001-5,0002,105 contacts →

Exact match

“Crum & Forster (C&F) provides market leading property & casualty, accident & health, specialty and standard commercial lines insurance solutions.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
13Exact matchHouston, TX, United StatesHQ recorded Sep 15, 20261,001-5,0002,006 contacts →

Exact match

“Tokio Marine HCC focuses on what matters most; our people.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
14Exact matchBoston, MA, United StatesHQ recorded Sep 15, 20261,001-5,0001,799 contacts →

Exact match

“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…”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
15Exact matchPeoria, IL, United StatesHQ recorded Sep 15, 20261,001-5,0001,386 contacts →

Exact match

“RLI is a U.S-based specialty insurer that serves niche property, casualty and surety markets.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
16Exact matchWayne, PA, United StatesHQ recorded Sep 15, 20261,001-5,0001,314 contacts →

Exact match

“We aspire to be the very best insurance company at underwriting insurance products for our customers.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
17Exact matchSan Diego, CA, United StatesHQ recorded Sep 15, 20261,001-5,0001,266 contacts →

Exact match

“ICW Group Insurance Companies is a top-tier, national, multi-line Property & Casualty insurance company, providing comprehensive coverage to safeguard our customers’ world.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
18Exact matchPhiladelphia, PA, United StatesHQ recorded Sep 15, 20261,001-5,0001,262 contacts →

Exact match

“ESIS®, Inc.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
19Exact matchMiddleton, WI, United StatesHQ recorded Sep 15, 2026201-5001,145 contacts →

Exact match

“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…”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
20Exact matchJersey City, NJ, United StatesHQ recorded Sep 15, 20265,001-10,0001,097 contacts →

Exact match

“Underwriting solutions at Verisk is a leading provider of advanced tools and analytics for the property/casualty and life insurance industries.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
21Exact matchChicago, IL, United StatesHQ recorded Sep 15, 20265,001-10,0001,079 contacts →

Exact match

“Ryan Specialty (NYSE: RYAN) is an international specialty insurance firm that provides distribution, underwriting, product development, administration and risk management services…”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
22Exact matchSarasota, FL, United StatesHQ recorded Sep 15, 2026501-1,0001,036 contacts →

Exact match

“FCCI Insurance Group provides commercial property and casualty insurance.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
23Exact matchCedar Rapids, IA, United StatesHQ recorded Sep 15, 2026501-1,0001,008 contacts →

Exact match

“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…”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
24Exact matchNew York, NY, United StatesHQ recorded Sep 15, 2026501-1,000851 contacts →

Exact match

“Argo Group is a U.S-focused underwriter of specialty insurance products in the property and casualty market.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase
25Exact matchWilkes-barre, PA, United StatesHQ recorded Sep 15, 20261,001-5,000843 contacts →

Exact match

“Rated A+ Superior by AM Best (as of 8/13/25), Berkshire Hathaway GUARD Insurance Companies provides Property & Casualty insurance including Excess & Surplus lines.”

Recorded in the RevenueBase company graph · Sep 15, 2026 · View company records in RevenueBase

Showing 25 of 874 casualty insurance underwriting companies based in the United States

See the full list, filter by size, metro and specialty, and access 72,079 tracked professional contacts with verified work emails. Direct dials are available where recorded.

Free signup · no credit card

View the full list →

Casualty insurance underwriting companies based in the United States at a glance

As of Sep 15, 2026
46.6%Verified-email coverage
176.9Average contacts per company
11-50Median size (employees)
3.1%Largest-city concentration · New York
Sep 15, 2026Page data refreshed

Companies by employee count

1-10
372
11-50
283
51-200
98
201-500
53
501-1,000
26
1,001-5,000
27
5,001-10,000
8
10001+
6

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

The recorded descriptions help you assess these company matches. Check a company’s website for its current services and locations.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase SmartSearch, the natural-language company search available to every RevenueBase user.
What qualifies
Company records associated with the United States whose business descriptions match “casualty insurance underwriting companies” by meaning at the Exact setting. Descriptions are compiled in the RevenueBase company graph from public websites, profiles and company information where available; they are not guaranteed quotations from the company's website.
RevenueBase SmartSearch
Describe a niche company in your own words to find businesses by meaning. Exact, Similar, Related and Broad control the breadth of RevenueBase SmartSearch. This saved list uses Exact. Each row's Exact match badge shows inclusion in that search, not an individual score or a service-quality judgment.
Public preview
The public preview omits records without a verified work email. Where headquarters information is recorded, preview rows are also filtered to this page’s location. Dataset totals and geographic summaries describe the full matched records before these preview filters.
Match quality
RevenueBase's August 25, 2026 study assessed 4,198 description/company pairs across matching settings. The publisher reports 86% good or better at Exact. This evaluates the method across queries; it does not audit this individual list. Recorded company descriptions, where available, help you judge each match yourself. Read the full methodology: how the lists are built and what the study measures.
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 displayed company carries at least one verified work email. RevenueBase tracks 72,079 professional contacts with verified work emails across the full matched dataset. 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.
Record context
Company records and descriptions can change. Check the company's website for its current services and locations.

Frequently asked

What is RevenueBase SmartSearch?

RevenueBase SmartSearch finds niche companies by the meaning of their business descriptions in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit your description. This list uses Exact for “casualty insurance underwriting companies”; each Exact match badge shows search membership, not an individual similarity or quality score.

How many casualty insurance underwriting companies are there based in the United States?

RevenueBase identified 874 company matches for casualty insurance underwriting companies associated with the United States as of September 2026, using the meaning of business descriptions at Exact. This is the recorded matched set in the RevenueBase company graph.

What is the largest company on this list?

Travelers tops the displayed preview by professional contacts tracked in RevenueBase. Recorded headquarters appear in the company rows.

Which city has the most casualty insurance underwriting companies?

New York leads with 27 company records, 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 limited free results with 500 credits to start. Upgrading provides access to the 72,079 professional contacts with verified work emails tracked across these 874 companies; direct dials are available where recorded.

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.

Ready to reach these companies? Verified emails and direct dials for all 874 casualty insurance underwriting companies based in the United States. Start with a free account, no credit card.

Download this list →

Related lists

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 SmartSearch, 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.