Company lists · Data refreshed September 2026

Top 25 Inland marine insurance underwriters based in the United States

Name: Inland marine insurance underwriters based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 17, 2026 77 companies tracked

RevenueBase identified 77 inland marine insurance underwriters headquartered in the United States as of September 2026 and tracks 2,453 professional contacts across them, including 1,410 with verified work emails. Houston is the largest hub.

This list covers inland marine insurance underwriters 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 17, 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.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 17, 2026 86% judged on-target in blind review

77Companies

2,453Contacts tracked

1,410Verified emails

Explore this list → Free signup · no credit card · 500 free credits

The 25 largest inland marine insurance underwriters based in the United States

Ranked by team size

Top 25 of 77 inland marine insurance underwriters based in the United States, ranked by team size, largest first. Data refreshed Sep 17, 2026. RevenueBase Smart Search rates how each company's information relates to inland marine insurance underwriters: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Core Specialty Insurance Holdings, INC	Strong evidence	Cincinnati, OH, United StatesHQ checked Sep 17, 2026	1,001-5,000	635 contacts →
	Strong evidence “Core Specialty, through its subsidiary insurers, offers a diversified range of property, casualty, and marine insurance products for small to mid-sized businesses.” Source: RevenueBase Database · checked Sep 17, 2026
2	Palomar	Indirect evidence	La Jolla, CA, United StatesHQ checked Sep 17, 2026	501-1,000	363 contacts →
	Indirect evidence “Founded in 2014, by a team with deep experience across underwriting, analytics, reinsurance and capital markets, Palomar is an innovative specialty insurer serving residential and…” Source: RevenueBase Database · checked Sep 17, 2026
3	Atlantic Casualty Insurance CO	Strong evidence	Goldsboro, NC, United StatesHQ checked Sep 17, 2026	201-500	335 contacts →
	Strong evidence “Atlantic Casualty Insurance Company (Atlantic Casualty) was formed by Strickland Insurance Group (SIG) in 1983 to underwrite a substantial book of non-standard personal auto.” Source: RevenueBase Database · checked Sep 17, 2026
4	Turn Services	Indirect evidence	New Orleans, LA, United StatesHQ checked Sep 17, 2026	201-500	133 contacts →
	Indirect evidence “Turn Services is one of the largest independent fleeting and shifting companies in the United States.” Source: RevenueBase Database · checked Sep 17, 2026
5	Cochrane & Company	Indirect evidence	Spokane, WA, United StatesHQ checked Sep 17, 2026	51-200	71 contacts →
	Indirect evidence “Cochrane & Company was established in 1960 in Spokane, Washington.” Source: RevenueBase Database · checked Sep 17, 2026
6	Berkley Fire & Marine A Berkley Company	Strong evidence	Schaumburg, IL, United StatesHQ checked Sep 17, 2026	5,001-10,000	62 contacts →
	Strong evidence “Berkley Fire & Marine was launched in 2013 and is a Berkley company offering preferred inland marine and related property risks and services.” Source: RevenueBase Database · checked Sep 17, 2026
7	Universal Fire & Casualty Insurance Company	Strong evidence	Waterford, MI, United StatesHQ checked Sep 17, 2026	11-50	49 contacts →
	Strong evidence “Universal Fire & Casualty Insurance Company (UFCIC) currently underwrites commercial property, general liability, business owner’s package (BOP), commercial multi-peril (CMP), and…” Source: RevenueBase Database · checked Sep 17, 2026
8	International Marine Underwriters	Strong evidence	New York, NY, United StatesHQ checked Sep 17, 2026	201-500	49 contacts →
	Strong evidence “International Marine Underwriters (IMU) traces its roots to the early 1900s, and offers a full range of ocean and inland marine insurance solutions.” Source: RevenueBase Database · checked Sep 17, 2026
9	Deans & Homer	Indirect evidence	San Francisco, CA, United StatesHQ checked Sep 17, 2026	51-200	44 contacts →
	Indirect evidence “Deans & Homer was established in 1856 and is one of the oldest continuously operating companies in California.” Source: RevenueBase Database · checked Sep 17, 2026
10	Riscom Regional Insurance Services Company, LLC	Strong evidence	Shreveport, LA, United StatesHQ checked Sep 17, 2026	51-200	42 contacts →
	Strong evidence “We are a professional insurance underwriting management company specializing in Commercial Automobile, Commercial General Liability, Commercial Property, Inland Marine and Garage…” Source: RevenueBase Database · checked Sep 17, 2026
11	One80 Marine	Partial evidence	Westbrook, CT, United StatesHQ checked Sep 17, 2026	51-200	42 contacts →
	Partial evidence “Our history dates back to the early 1990’s, when Maritime General Agency and Marine MGA were founded.” Source: RevenueBase Database · checked Sep 17, 2026
12	OLD Republic Inland Marine	Strong evidence	Chicago, IL, United StatesHQ checked Sep 17, 2026	201-500	37 contacts →
	Strong evidence “Old Republic Inland Marine is a collaborative team of highly specialized, experienced underwriters with the authority to deliver thoughtful, timely underwriting decisions for…” Source: RevenueBase Database · checked Sep 17, 2026
13	Trident Marine Managers	Strong evidence	Houston, TX, United StatesHQ checked Sep 17, 2026	11-50	25 contacts →
	Strong evidence “Trident Marine Managers is a leading specialty marine and offshore energy managing general underwriter (MGU) that delivers capacity and solid protection.” Source: RevenueBase Database · checked Sep 17, 2026
14	Nbis, A Dual Company	Partial evidence	Atlanta, GA, United StatesHQ checked Sep 17, 2026	51-200	25 contacts →
	Partial evidence “NBIS specializes in providing policyholders with the most effective risk management products and innovative insurance solutions for the heavy construction and related…” Source: RevenueBase Database · checked Sep 17, 2026
15	Continental Underwriters, LTD	Strong evidence	Covington, LA, United StatesHQ checked Sep 17, 2026	11-50	18 contacts →
	Strong evidence “Continental Underwriters, Ltd, provides all classes of commercial marine insurance coverages.” Source: RevenueBase Database · checked Sep 17, 2026
16	International Special Risks	Strong evidence	Lynnfield, MA, United StatesHQ checked Sep 17, 2026	11-50	16 contacts →
	Strong evidence “International Special Risks, Inc.(ISR), with offices from Maine to Florida, is the largest Marine intermediary insurance broker on the East Coast.” Source: RevenueBase Database · checked Sep 17, 2026
17	Pmer Insurance Services	Strong evidence	Milwaukie, OR, United StatesHQ checked Sep 17, 2026	1-10	14 contacts →
	Strong evidence “Business and Personal Insurance; Special programs; Wet Marine experts (Yachts, Fish Boats, Charter Boats, marinas, etc); Workers' Compensation placements (all state); Lloyds of…” Source: RevenueBase Database · checked Sep 17, 2026
18	Seven Seas Insurance Company	Partial evidence	Riviera Beach, FL, United StatesHQ checked Sep 17, 2026	11-50	13 contacts →
	Partial evidence “Seven Seas Insurance Company specializes in cargo insurance.” Source: RevenueBase Database · checked Sep 17, 2026
19	AMG Insurance International LLC	Strong evidence	West Palm Beach, FL, United StatesHQ checked Sep 17, 2026	1-10	10 contacts →
	Strong evidence “AMG Insurance International was established to fill the relationship gap in the marine insurance industry.” Source: RevenueBase Database · checked Sep 17, 2026
20	Boater's Insurance Agency, INC	Partial evidence	Danville, CA, United StatesHQ checked Sep 17, 2026	11-50	7 contacts →
	Partial evidence “Founded in 1989 by Hillary Swiggett, Boater’s Insurance Agency, Inc.(BIA) is a family owned and operated agency that specializes in providing insurance products and services…” Source: RevenueBase Database · checked Sep 17, 2026
21	Skisafe	Partial evidence	New Hyde Park, NY, United StatesHQ checked Sep 17, 2026	11-50	6 contacts →
	Partial evidence “SkiSafe™ is a premier “specialty” provider of personal pleasure boat, yacht, and watercraft insurance.” Source: RevenueBase Database · checked Sep 17, 2026
22	Capacity Marine Corporation	Strong evidence	Mahwah, NJ, United StatesHQ checked Sep 17, 2026	1-10	6 contacts →
	Strong evidence “Capacity Marine Corporation is an insurance company based out of 1 International Blvd, Mahwah, New Jersey, United States.” Source: RevenueBase Database · checked Sep 17, 2026
23	American Marine Insurance SVC	Partial evidence	Ventura, CA, United StatesHQ checked Sep 17, 2026	1-10	5 contacts →
	Partial evidence “Our Founder is a former Merchant Mariner and we've stayed true to our marine roots.” Source: RevenueBase Database · checked Sep 17, 2026
24	Southern Marine	Strong evidence	Houston, TX, United StatesHQ checked Sep 17, 2026	1-10	5 contacts →
	Strong evidence “Southern Marine is a marine insurance specialist headquartered in Houston, Texas.” Source: RevenueBase Database · checked Sep 17, 2026
25	Inland Marine Underwriters Association Imua	Strong evidence	New York, NY, United StatesHQ checked Sep 17, 2026	1-10	4 contacts →
	Strong evidence “Founded in 1930, Inland Marine Underwriters Association (IMUA) is the national association for the commercial inland marine insurance industry in the US.” Source: RevenueBase Database · checked Sep 17, 2026

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: inland marine insurance underwriters. 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 inland marine insurance underwriters.
Partial evidence: Its own public description names part of inland marine insurance underwriters, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name inland marine insurance underwriters. 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 77 inland marine insurance underwriters based in the United States

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 1,410 reachable decision-makers.

Free signup · no credit card

View the full list →

Inland marine insurance underwriters based in the United States at a glance

As of Sep 17, 2026

57.5%Verified-email coverage

31.9Average contacts per company

1-10Median size (employees)

3.9%Largest-city concentration · Houston

Sep 17, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

501-1,000

1,001-5,000

5,001-10,000

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 77 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 inland marine insurance underwriters, 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 “inland marine insurance underwriters”. 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 inland marine insurance underwriters), 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 inland marine insurance underwriters, 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, 1,410 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 17, 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.

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 inland marine insurance underwriters, 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 inland marine insurance underwriters are there based in the United States?

RevenueBase identified 77 inland marine insurance underwriters 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?

Core Specialty Insurance Holdings, INC, headquartered in Cincinnati, tops this list with the largest team on record.

Which city has the most inland marine insurance underwriters?

Houston leads with 3 headquartered companies, followed by New Orleans (3) and New York (3).

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 1,410 verified decision-maker contacts tracked across these 77 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 17, 2026.

Ready to reach these companies? Verified emails and direct dials for all 77 inland marine insurance underwriters based in the United States. Start with a free account, no credit card.

Download this list →

Related lists

Browse the directory

Browse: Companies home · All United States lists · All Inland marine insurance underwriters lists · New 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 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.