Company lists · Data refreshed September 2026

Top 25 Internet security companies based in the United States

Name: Internet security companies based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 21, 2026 790 companies tracked

RevenueBase identified 790 internet security companies headquartered in the United States as of September 2026 and tracks 67,723 professional contacts across them, including 29,506 with verified work emails. New York is the largest hub.

This list covers internet security 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 21, 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 21, 2026 86% judged on-target in blind review

790Companies

67,723Contacts tracked

29,506Verified emails

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The 25 largest internet security companies based in the United States

Ranked by team size

Top 25 of 790 internet security companies based in the United States, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to internet security companies: 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	Palo Alto Networks	Indirect evidence	Santa Clara, CA, United StatesHQ checked Sep 21, 2026	10001+	18,431 contacts →
	Indirect evidence “Palo Alto Networks, the global cybersecurity leader, is shaping the cloud-centric future with technology that is transforming the way people and organizations operate.” Source: RevenueBase Database · checked Sep 21, 2026
2	Fortinet	Indirect evidence	Sunnyvale, CA, United StatesHQ checked Sep 21, 2026	10001+	14,289 contacts →
	Indirect evidence “Fortinet makes possible a digital world that we can always trust through its mission to protect people, devices, and data everywhere.” Source: RevenueBase Database · checked Sep 21, 2026
3	Symantec	Partial evidence	San Jose, CA, United StatesHQ checked Sep 21, 2026	10001+	11,169 contacts →
	Partial evidence “Your backstage pass to the most epic cybersecurity solutions on the market for Endpoint, Network, Data and Cloud security.” Source: RevenueBase Database · checked Sep 21, 2026
4	Mcafee	Indirect evidence	San Jose, CA, United StatesHQ checked Sep 21, 2026	1,001-5,000	4,868 contacts →
	Indirect evidence “We’re creating what’s next in online protection.” Source: RevenueBase Database · checked Sep 21, 2026
5	Barracuda	Indirect evidence	Campbell, CA, United StatesHQ checked Sep 21, 2026	1,001-5,000	2,157 contacts →
	Indirect evidence “Barracuda is a leading global cybersecurity company providing complete protection against complex threats for all size business.” Source: RevenueBase Database · checked Sep 21, 2026
6	Imperva	Indirect evidence	Austin, TX, United StatesHQ checked Sep 21, 2026	10001+	1,217 contacts →
	Indirect evidence “On Dec.” Source: RevenueBase Database · checked Sep 21, 2026
7	Trustwave, A Levelblue Company	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 21, 2026	501-1,000	874 contacts →
	Indirect evidence “Trustwave, a LevelBlue Company, is a globally recognized cybersecurity leader that reduces cyber risk and fortifies organizations against disruptive and damaging cyber threats.” Source: RevenueBase Database · checked Sep 21, 2026
8	Nortonlifelock	Indirect evidence	Tempe, AZ, United StatesHQ checked Sep 21, 2026	n/a	740 contacts →
	Indirect evidence “NortonLifeLock and Avast merged in 2022 and are now Gen™ (NASDAQ: GEN)- a global company dedicated to powering Digital Freedom through its trusted Cyber Safety brands.” Source: RevenueBase Database · checked Sep 21, 2026
9	Vectra AI	Indirect evidence	San Jose, CA, United StatesHQ checked Sep 21, 2026	501-1,000	651 contacts →
	Indirect evidence “Vectra AI is the cybersecurity AI leader in protecting modern networks from modern attacks.” Source: RevenueBase Database · checked Sep 21, 2026
10	Malwarebytes	Partial evidence	Santa Clara, CA, United StatesHQ checked Sep 21, 2026	501-1,000	604 contacts →
	Partial evidence “Malwarebytes is reimagining security to safeguard devices, data, and people, no matter their location, lifestyle or means.” Source: RevenueBase Database · checked Sep 21, 2026
11	Comodo	Partial evidence	Bloomfield, NJ, United StatesHQ checked Sep 21, 2026	51-200	566 contacts →
	Partial evidence “Comodo - Protecting Your Digital World At Comodo, we are dedicated to safeguarding your digital property with Comodo Website Security.” Source: RevenueBase Database · checked Sep 21, 2026
12	Guidance Software	Indirect evidence	Pasadena, CA, United StatesHQ checked Sep 21, 2026	501-1,000	492 contacts →
	Indirect evidence “Guidance (NASDAQ: GUID) exists to turn chaos and the unknown into order and the known-so that companies and their customers can go about their daily lives as usual without worry…” Source: RevenueBase Database · checked Sep 21, 2026
13	DUO Security	Partial evidence	Ann Arbor, MI, United StatesHQ checked Sep 21, 2026	501-1,000	435 contacts →
	Partial evidence “We are Duo, and we’re here to democratize security.” Source: RevenueBase Database · checked Sep 21, 2026
14	Novacoast	Partial evidence	Wichita, KS, United StatesHQ checked Sep 21, 2026	201-500	369 contacts →
	Partial evidence “Novacoast is an international cybersecurity company specializing in IT services and software development.” Source: RevenueBase Database · checked Sep 21, 2026
15	Cujo AI	Indirect evidence	Covina, CA, United StatesHQ checked Sep 21, 2026	201-500	239 contacts →
	Indirect evidence “CUJO AI® is the global leader of cutting-edge cybersecurity and network intelligence solutions that enable network operators globally to improve the digital life protection of…” Source: RevenueBase Database · checked Sep 21, 2026
16	Carbon Black	Partial evidence	Palo Alto, CA, United StatesHQ checked Sep 21, 2026	1,001-5,000	239 contacts →
	Partial evidence “Your backstage pass to the most epic cybersecurity solutions on the market for Endpoint, Network, Data and Cloud security.” Source: RevenueBase Database · checked Sep 21, 2026
17	Hillstone Networks	Partial evidence	Santa Clara, CA, United StatesHQ checked Sep 21, 2026	1,001-5,000	230 contacts →
	Partial evidence “Hillstone Networks’ Integrative Cyber Security approach delivers coverage, control, and consolidation to secure digital transformation for more than enterprises worldwide.” Source: RevenueBase Database · checked Sep 21, 2026
18	Webroot	Indirect evidence	Broomfield, CO, United StatesHQ checked Sep 21, 2026	501-1,000	199 contacts →
	Indirect evidence “Webroot, an OpenText company, was the first to harness the cloud and artificial intelligence to stop zero-day threats in real time.” Source: RevenueBase Database · checked Sep 21, 2026
19	Eset North America	Indirect evidence	San Diego, CA, United StatesHQ checked Sep 21, 2026	51-200	180 contacts →
	Indirect evidence “For more than 30 years we have been here helping to watch over and protect progress.” Source: RevenueBase Database · checked Sep 21, 2026
20	Xcitium	Partial evidence	Remote, United StatesHQ checked Sep 21, 2026	501-1,000	171 contacts →
	Partial evidence “Prevention-First Cybersecurity Powered by Patented ZeroDwell Containment Xcitium (formerly Comodo Security Solutions) is redefining cybersecurity with a prevention-first approach.” Source: RevenueBase Database · checked Sep 21, 2026
21	Defendedge	Indirect evidence	Elmhurst, IL, United StatesHQ checked Sep 21, 2026	51-200	167 contacts →
	Indirect evidence “DefendEdge is a leading US-based cybersecurity firm specializing in protecting clients' firewalls, endpoints, and applications against cyber threats and vulnerabilities.” Source: RevenueBase Database · checked Sep 21, 2026
22	At&t Cybersecurity	Partial evidence	Dallas, TX, United StatesHQ checked Sep 21, 2026	1,001-5,000	156 contacts →
	Partial evidence “AT & T Cybersecurity’s Edge-to-Edge technologies provide phenomenal threat intelligence, collaborative defense, security without the seams, and solutions that fit your business.” Source: RevenueBase Database · checked Sep 21, 2026
23	Sq1 Security	Partial evidence	Dallas, TX, United StatesHQ checked Sep 21, 2026	201-500	154 contacts →
	Partial evidence “SQ1 Security is a global cybersecurity leader offering end-to-end cybersecurity and compliance solution.” Source: RevenueBase Database · checked Sep 21, 2026
24	ESOFT	Partial evidence	Broomfield, CO, United StatesHQ checked Sep 21, 2026	51-200	141 contacts →
	Partial evidence “eSoft is a leader in providing Simply Better Network Security™ to businesses of nearly any size.” Source: RevenueBase Database · checked Sep 21, 2026
25	Tripwire	Indirect evidence	Portland, OR, United StatesHQ checked Sep 21, 2026	201-500	128 contacts →
	Indirect evidence “Tripwire is proud to be part of Fortra’s comprehensive cybersecurity portfolio.” Source: RevenueBase Database · checked Sep 21, 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: internet security 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 internet security companies.
Partial evidence: Its own public description names part of internet security companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name internet security 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 790 internet security companies based in the United States

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Internet security companies based in the United States at a glance

As of Sep 21, 2026

43.6%Verified-email coverage

85.7Average contacts per company

1-10Median size (employees)

2.7%Largest-city concentration · New York

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

400

11-50

241

51-200

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

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 790 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 internet security 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 “internet security 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 internet security 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 internet security 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, 29,506 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 21, 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 internet security 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 internet security companies are there based in the United States?

RevenueBase identified 790 internet security 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?

Palo Alto Networks, headquartered in Santa Clara, tops this list with the largest team on record.

Which city has the most internet security companies?

New York leads with 21 headquartered companies, followed by Austin (15) and San Jose (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 29,506 verified decision-maker contacts tracked across these 790 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 21, 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.