Company lists · Data refreshed September 2026

Top 25 Underwriting companies based in the United States

RevenueBase identified 2,227 company matches for underwriting companies associated with the United States as of September 2026 and tracks 213,754 professional contacts across them, including 97,287 with verified work emails. New York is the largest hub.

This list covers company matches for 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 22, 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 22, 2026 How this list was built
2,227Companies
213,754Contacts tracked
97,287Verified emails
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The 25 largest underwriting companies based in the United States

Ranked by team size
Top 25 of 2,227 company matches for underwriting companies based in the United States, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Sep 22, 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 22, 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 22, 2026 · View company records in RevenueBase
2Exact matchNew York, NY, United StatesHQ recorded Sep 22, 202610001+23,438 contacts →

Exact match

“American International Group, Inc.(NYSE: AIG) is a leading global insurance organization.”

Recorded in the RevenueBase company graph · Sep 22, 2026 · View company records in RevenueBase
3Exact matchChicago, IL, United StatesHQ recorded Sep 22, 202610001+14,217 contacts →

Exact match

“Hi, we’re HUB.”

Recorded in the RevenueBase company graph · Sep 22, 2026 · View company records in RevenueBase
4Exact matchWhite Plains, NY, United StatesHQ recorded Sep 22, 202610001+9,086 contacts →

Exact match

“Marsh McLennan Agency, a business of Marsh (NYSE: MRSH), is a leading provider of business insurance, employee health & benefits, retirement & wealth, and private client insurance…”

Recorded in the RevenueBase company graph · Sep 22, 2026 · View company records in RevenueBase
5Exact matchSchaumburg, IL, United StatesHQ recorded Sep 22, 20265,001-10,0008,988 contacts →

Exact match

“Zurich North America is one of the largest providers of insurance solutions and services to businesses and individuals.”

Recorded in the RevenueBase company graph · Sep 22, 2026 · View company records in RevenueBase
6Exact matchChicago, IL, United StatesHQ recorded Sep 22, 20265,001-10,0006,984 contacts →

Exact match

“CNA is one of the largest U.S.”

Recorded in the RevenueBase company graph · Sep 22, 2026 · View company records in RevenueBase
7Exact matchChicago, IL, United StatesHQ recorded Sep 22, 20265,001-10,0005,419 contacts →

Exact match

“The Kemper family of companies is one of the nation’s leading specialized insurers.”

Recorded in the RevenueBase company graph · Sep 22, 2026 · View company records in RevenueBase
8Exact matchCharlotte, NC, United StatesHQ recorded Sep 22, 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 22, 2026 · View company records in RevenueBase
9Exact matchChesterfield, MO, United StatesHQ recorded Sep 22, 20261,001-5,0004,128 contacts →

Exact match

“Reinsurance Group of America, Incorporated (NYSE: RGA) is a global industry leader specializing in life and health reinsurance and financial solutions that help clients…”

Recorded in the RevenueBase company graph · Sep 22, 2026 · View company records in RevenueBase
10Exact matchStevens Point, WI, United StatesHQ recorded Sep 22, 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 22, 2026 · View company records in RevenueBase
11Exact matchWarren, NJ, United StatesHQ recorded Sep 22, 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 22, 2026 · View company records in RevenueBase
12Exact matchGlen Allen, VA, United StatesHQ recorded Sep 22, 20261,001-5,0003,151 contacts →

Exact match

“As the insurance operations within the Markel Group Inc.(NYSE: MKL), we leverage a broad array of capabilities and expertise to create intelligent solutions for the most complex…”

Recorded in the RevenueBase company graph · Sep 22, 2026 · View company records in RevenueBase
13Exact matchCharlotte, NC, United StatesHQ recorded Sep 22, 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 22, 2026 · View company records in RevenueBase
14Exact matchChicago, IL, United StatesHQ recorded Sep 22, 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 22, 2026 · View company records in RevenueBase
15Exact matchBoston, MA, United StatesHQ recorded Sep 22, 20265,001-10,0002,206 contacts →

Exact match

“At Risk Strategies, part of the Brown & Brown team, we help our clients protect those things that matter most to them.”

Recorded in the RevenueBase company graph · Sep 22, 2026 · View company records in RevenueBase
16Exact matchMorristown, NJ, United StatesHQ recorded Sep 22, 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 22, 2026 · View company records in RevenueBase
17Exact matchHouston, TX, United StatesHQ recorded Sep 22, 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 22, 2026 · View company records in RevenueBase
18Exact matchNew York, NY, United StatesHQ recorded Sep 22, 202610001+1,883 contacts →

Exact match

“At QBE we’re driven by our purpose of enabling a more resilient future.”

Recorded in the RevenueBase company graph · Sep 22, 2026 · View company records in RevenueBase
19Exact matchBoston, MA, United StatesHQ recorded Sep 22, 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 22, 2026 · View company records in RevenueBase
20Exact matchDeerfield, IL, United StatesHQ recorded Sep 22, 20261,001-5,0001,643 contacts →

Exact match

“Alera Group is a growing leader, reimagining the complex risk management, insurance and financial services delivery experience through intentional collaboration connecting clients…”

Recorded in the RevenueBase company graph · Sep 22, 2026 · View company records in RevenueBase
21Exact matchPlymouth, MN, United StatesHQ recorded Sep 22, 20261,001-5,0001,388 contacts →

Exact match

“We are here to help people, businesses and society prosper in good times and be resilient in bad times.”

Recorded in the RevenueBase company graph · Sep 22, 2026 · View company records in RevenueBase
22Exact matchPeoria, IL, United StatesHQ recorded Sep 22, 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 22, 2026 · View company records in RevenueBase
23Exact matchWayne, PA, United StatesHQ recorded Sep 22, 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 22, 2026 · View company records in RevenueBase
24Exact matchMiddleton, WI, United StatesHQ recorded Sep 22, 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 22, 2026 · View company records in RevenueBase
25Exact matchCincinnati, OH, United StatesHQ recorded Sep 22, 20261,001-5,0001,113 contacts →

Exact match

“American Modern provides insurance solutions for customers who need coverage not readily found in the general market.”

Recorded in the RevenueBase company graph · Sep 22, 2026 · View company records in RevenueBase

Showing 25 of 2,227 underwriting companies based in the United States

See the full list, filter by size, metro and specialty, and access 97,287 tracked professional contacts with verified work emails. Direct dials are available where recorded.

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Underwriting companies based in the United States at a glance

As of Sep 22, 2026
45.5%Verified-email coverage
96.0Average contacts per company
11-50Median size (employees)
3.2%Largest-city concentration · New York
Sep 22, 2026Page data refreshed

Companies by employee count

1-10
1,010
11-50
736
51-200
248
201-500
79
501-1,000
37
1,001-5,000
48
5,001-10,000
14
10001+
51

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 2,227 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 “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 97,287 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 22, 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 “underwriting companies”; each Exact match badge shows search membership, not an individual similarity or quality score.

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

RevenueBase identified 2,227 company matches for 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 underwriting companies?

New York leads with 72 company records, followed by Houston (47) and Chicago (41).

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 97,287 professional contacts with verified work emails tracked across these 2,227 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 22, 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 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.