Company lists · Data refreshed September 2026

Top 25 Managed security companies based in the United States

RevenueBase identified 6,000 managed security companies headquartered in the United States as of September 2026 and tracks 237,217 professional contacts across them, including 66,389 with verified work emails. New York is the largest hub.

This list covers managed 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
6,000Companies
237,217Contacts tracked
66,389Verified emails
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The 25 largest managed security companies based in the United States

Ranked by team size
Top 25 of 6,000 managed 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 managed 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.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Partial evidenceParsippany, NJ, United StatesHQ checked Sep 21, 202610001+38,634 contacts →

Partial evidence

Securitas knows Security.”

Source: RevenueBase Database · checked Sep 21, 2026
2Indirect evidenceSanta Clara, CA, United StatesHQ checked Sep 21, 202610001+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
3Indirect evidenceSunnyvale, CA, United StatesHQ checked Sep 21, 202610001+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
4Partial evidenceSt. Petersburg, FL, United StatesHQ checked Sep 21, 2026n/a4,038 contacts →

Partial evidence

“Excelsior Defense is a security and investigations company based out of St.”

Source: RevenueBase Database · checked Sep 21, 2026
5Partial evidencePasadena, CA, United StatesHQ checked Sep 21, 202610001+3,612 contacts →

Partial evidence

“EVERYWHERE SECURITY MATTERS.”

Source: RevenueBase Database · checked Sep 21, 2026
6Indirect evidenceRoswell, GA, United StatesHQ checked Sep 21, 202610001+3,592 contacts →

Indirect evidence

“U.S.”

Source: RevenueBase Database · checked Sep 21, 2026
7Indirect evidenceEden Prairie, MN, United StatesHQ checked Sep 21, 20261,001-5,0003,145 contacts →

Indirect evidence

“Every year new technologies, vendors, and solutions emerge-yet despite this constant innovation, high-profile breaches are all over the headlines.”

Source: RevenueBase Database · checked Sep 21, 2026
8Indirect evidenceMountain View, CA, United StatesHQ checked Sep 21, 20261,001-5,0003,052 contacts →

Indirect evidence

“SentinelOne is the world's leading AI-powered cybersecurity platform.”

Source: RevenueBase Database · checked Sep 21, 2026
9Partial evidenceBoston, MA, United StatesHQ checked Sep 21, 20261,001-5,0002,822 contacts →

Partial evidence

“Rapid7, Inc.(NASDAQ: RPD) is a global leader in AI-powered managed cybersecurity operations, trusted to advance organizations’ cyber resilience.”

Source: RevenueBase Database · checked Sep 21, 2026
10Partial evidenceCulver City, CA, United StatesHQ checked Sep 21, 20265,001-10,0002,500 contacts →

Partial evidence

“The industry leader in security, Security Industry Specialists offers unique solutions to Fortune 500 companies, international events, and celebrity clients.”

Source: RevenueBase Database · checked Sep 21, 2026
11Indirect evidenceLeawood, KS, United StatesHQ checked Sep 21, 20261,001-5,0002,222 contacts →

Indirect evidence

“Optiv is the cyber advisory and solutions leader, delivering strategic and technical expertise to nearly companies across every major industry.”

Source: RevenueBase Database · checked Sep 21, 2026
12Strong evidenceChattanooga, TN, United StatesHQ checked Sep 21, 20265,001-10,0002,174 contacts →

Strong evidence

“Through an ISO® 9001:2015 Certified Quality Management System (QMS), Walden Security has earned an award-winning reputation for business excellence and employee satisfaction…”

Source: RevenueBase Database · checked Sep 21, 2026
13Indirect evidenceCampbell, CA, United StatesHQ checked Sep 21, 20261,001-5,0002,157 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
14Indirect evidenceSanta Ana, CA, United StatesHQ checked Sep 21, 202610001+2,073 contacts →

Indirect evidence

“We've merged!”

Source: RevenueBase Database · checked Sep 21, 2026
15Partial evidenceRaleigh, NC, United StatesHQ checked Sep 21, 20265,001-10,0001,639 contacts →

Partial evidence

“Sunstates Security, LLC is one of the industry's leading providers of contract security services with a differentiated approach to providing successful, cost-effective, quality…”

Source: RevenueBase Database · checked Sep 21, 2026
16Strong evidenceBethesda, MD, United StatesHQ checked Sep 21, 20265,001-10,0001,441 contacts →

Strong evidence

“Admiral Security Services provides professional armed and unarmed uniformed security officers, unparalleled site management and unwavering corporate support that exceeds client…”

Source: RevenueBase Database · checked Sep 21, 2026
17Partial evidenceRomeoville, IL, United StatesHQ checked Sep 21, 20261,001-5,0001,406 contacts →

Partial evidence

“As of May 2016, Protection 1 and ADT merged together to become the leading company in the electronic security industry.”

Source: RevenueBase Database · checked Sep 21, 2026
18Partial evidenceNew Orleans, LA, United StatesHQ checked Sep 21, 20261,001-5,0001,399 contacts →

Partial evidence

“Weiser Security Services is the 11th largest security service provider in the U.S.”

Source: RevenueBase Database · checked Sep 21, 2026
19Partial evidenceWarrendale, PA, United StatesHQ checked Sep 21, 20261,001-5,0001,287 contacts →

Partial evidence

“Vector Security® has protected people and property by providing intelligent security solutions tailored to the needs of the customer for more than 50 years.”

Source: RevenueBase Database · checked Sep 21, 2026
20Partial evidenceTampa, FL, United StatesHQ checked Sep 21, 20261,001-5,0001,285 contacts →

Partial evidence

“ReliaQuest exists to Make Security Possible.”

Source: RevenueBase Database · checked Sep 21, 2026
21Indirect evidenceAustin, TX, United StatesHQ checked Sep 21, 20261,001-5,0001,252 contacts →

Indirect evidence

“Thales is a global leader in cybersecurity, helping the most trusted organizations in the world protect their most critical applications, data, and identities anywhere at scale.”

Source: RevenueBase Database · checked Sep 21, 2026
22Partial evidenceReston, VA, United StatesHQ checked Sep 21, 20261,001-5,0001,232 contacts →

Partial evidence

“GuidePoint Security provides trusted cybersecurity expertise, solutions, and services that help organizations make informed decisions and minimize risk.”

Source: RevenueBase Database · checked Sep 21, 2026
23Partial evidenceDothan, AL, United StatesHQ checked Sep 21, 20261,001-5,0001,190 contacts →

Partial evidence

“DSI Security Services offers armed and unarmed uniformed security guard services.”

Source: RevenueBase Database · checked Sep 21, 2026
24Partial evidenceParsippany, NJ, United StatesHQ checked Sep 21, 202610001+1,151 contacts →

Partial evidence

“SOS Security is a known innovator and leader in the security and protective services industry.”

Source: RevenueBase Database · checked Sep 21, 2026
25Partial evidenceChicago, IL, United StatesHQ checked Sep 21, 20261,001-5,0001,138 contacts →

Partial evidence

“At Titan Security Group, we understand that each client is unique, with specific security needs shaped by the type of property and its location.”

Source: RevenueBase Database · checked Sep 21, 2026

Showing 25 of 6,000 managed security companies based in the United States

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Managed security companies based in the United States at a glance

As of Sep 21, 2026
28.0%Verified-email coverage
39.5Average contacts per company
11-50Median size (employees)
2.7%Largest-city concentration · New York
Sep 21, 2026Page data refreshed

Companies by employee count

1-10
2,351
11-50
2,084
51-200
978
201-500
298
501-1,000
138
1,001-5,000
93
5,001-10,000
19
10001+
21

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 6,000 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 managed 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 “managed 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 managed 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 managed 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, 66,389 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 managed 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 managed security companies are there based in the United States?

RevenueBase identified 6,000 managed 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?

Securitas Security Services Usa, INC, headquartered in Parsippany, tops this list with the largest team on record.

Which city has the most managed security companies?

New York leads with 160 headquartered companies, followed by Houston (128) and Miami (118).

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 66,389 verified decision-maker contacts tracked across these 6,000 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.