Company lists · Data refreshed September 2026

Top 25 Managed security service providers based in the United States

RevenueBase identified 6,554 managed security service providers headquartered in the United States as of September 2026 and tracks 188,270 professional contacts across them, including 86,323 with verified work emails and 58,463 with mobile numbers. New York is the largest hub.

This list covers managed security service providers 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, how directly it supports the match, and when it was last checked. Data refreshed September 5, 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 HQ checked on every row Match evidence on every row Refreshed Sep 5, 2026 86% judged on-target in blind review
6,554Companies
188,270Contacts tracked
86,323Verified emails
58,463Mobile numbers
Unlock all 6,554 companies Free signup · no credit card · 500 free credits

The 25 largest managed security service providers based in the United States

Ranked by team size
Top 25 of 6,554 managed security service providers based in the United States, ranked by team size, largest first. Data refreshed Sep 5, 2026. Evidence rates how directly each company's own description names managed security service providers: strong (names it), partial (names part of it), indirect (matched on its full profile rather than the summary shown). Click a count to unlock that company's people.
#CompanyHeadquartersEmployeesContacts
1
Palo Alto NetworksIndirect evidence
Santa Clara, CA, United StatesHQ checked Sep 5, 202610001+18,431

“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: company website · checked Sep 5, 2026
2
FortinetIndirect evidence
Sunnyvale, CA, United StatesHQ checked Sep 5, 202610001+14,289

“Fortinet makes possible a digital world that we can always trust through its mission to protect people, devices, and data everywhere.”

Source: company website · checked Sep 5, 2026
3
SymantecPartial evidence
San Jose, CA, United StatesHQ checked Sep 5, 202610001+11,169

“Your backstage pass to the most epic cybersecurity solutions on the market for Endpoint, Network, Data and Cloud security.”

Source: company website · checked Sep 5, 2026
4
CrowdstrikePartial evidence
Remote, United StatesHQ checked Sep 5, 20265,001-10,00010,118

“CrowdStrike (Nasdaq: CRWD), a global cybersecurity leader, has redefined modern security with the world’s most advanced cloud-native platform for protecting critical areas of…”

Source: company website · checked Sep 5, 2026
5
BugcrowdPartial evidence
San Francisco, CA, United StatesHQ checked Sep 5, 2026n/a3,649

“We are a crowdsourced security company that safeguards organizations' assets from sophisticated threat actors before they can strike-by uniting our customers with trusted hackers…”

Source: company website · checked Sep 5, 2026
6
TrellixPartial evidence
Plano, TX, United StatesHQ checked Sep 5, 20261,001-5,0003,447

“Trellix is a global cybersecurity company delivering intelligence-led cyber resilience for security-conscious organizations at any stage of their journey.”

Source: company website · checked Sep 5, 2026
7
Arctic WolfIndirect evidence
Eden Prairie, MN, United StatesHQ checked Sep 5, 20261,001-5,0003,145

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

Source: company website · checked Sep 5, 2026
8
SentineloneIndirect evidence
Mountain View, CA, United StatesHQ checked Sep 5, 20261,001-5,0003,052

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

Source: company website · checked Sep 5, 2026
9
Rapid7Partial evidence
Boston, MA, United StatesHQ checked Sep 5, 20261,001-5,0002,822

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

Source: company website · checked Sep 5, 2026
10
OPTIVIndirect evidence
Leawood, KS, United StatesHQ checked Sep 5, 20261,001-5,0002,222

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

Source: company website · checked Sep 5, 2026
11
BarracudaIndirect evidence
Campbell, CA, United StatesHQ checked Sep 5, 20261,001-5,0002,157

“Barracuda is a leading global cybersecurity company providing complete protection against complex threats for all size business.”

Source: company website · checked Sep 5, 2026
12
FortraIndirect evidence
Eden Prairie, MN, United StatesHQ checked Sep 5, 20261,001-5,0001,648

“Fortra delivers AI-amplified cybersecurity solutions that help organizations use and protect data with confidence.”

Source: company website · checked Sep 5, 2026
13
ReliaquestPartial evidence
Tampa, FL, United StatesHQ checked Sep 5, 20261,001-5,0001,285

“ReliaQuest exists to Make Security Possible.”

Source: company website · checked Sep 5, 2026
14Austin, TX, United StatesHQ checked Sep 5, 20261,001-5,0001,252

“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: company website · checked Sep 5, 2026
15
Guidepoint SecurityPartial evidence
Reston, VA, United StatesHQ checked Sep 5, 20261,001-5,0001,232

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

Source: company website · checked Sep 5, 2026
16
ImpervaIndirect evidence
Austin, TX, United StatesHQ checked Sep 5, 202610001+1,217

“On Dec.”

Source: company website · checked Sep 5, 2026
17
Forescout Technologies INCIndirect evidence
San Jose, CA, United StatesHQ checked Sep 5, 20261,001-5,0001,181

“As AI-driven vulnerability and exploitation accelerate attack velocity to machine speed, Forescout is a foundational cyber defense layer that allows organizations to segment and…”

Source: company website · checked Sep 5, 2026
18
Watchguard TechnologiesIndirect evidence
Seattle, WA, United StatesHQ checked Sep 5, 20261,001-5,0001,059

“WatchGuard® Technologies, Inc.”

Source: company website · checked Sep 5, 2026
19
CoalfireIndirect evidence
Chicago, IL, United StatesHQ checked Sep 5, 20261,001-5,000947

“Coalfire is the premier Cybersecurity and Compliance Services leader for the tech, healthcare, and finance industries.(This page is maintained by Marketing.”

Source: company website · checked Sep 5, 2026
20
ZerofoxIndirect evidence
Baltimore, MD, United StatesHQ checked Sep 5, 2026501-1,000904

“ZeroFox is the solution to discover, validate, and disrupt external cyber threats before they harm revenue or reputation.”

Source: company website · checked Sep 5, 2026
21
NetenrichPartial evidence
San Jose, CA, United StatesHQ checked Sep 5, 2026501-1,000889

“Netenrich is redefining security operations by shifting the focus from "efficiency"(speed) to "efficacy"(comprehensive coverage).”

Source: company website · checked Sep 5, 2026
22Chicago, IL, United StatesHQ checked Sep 5, 2026501-1,000874

“Trustwave, a LevelBlue Company, is a globally recognized cybersecurity leader that reduces cyber risk and fortifies organizations against disruptive and damaging cyber threats.”

Source: company website · checked Sep 5, 2026
23
CyderesIndirect evidence
Kansas City, MO, United StatesHQ checked Sep 5, 20261,001-5,000844

“Today’s threatscape is relentless.”

Source: company website · checked Sep 5, 2026
24Lansing, MI, United StatesHQ checked Sep 5, 2026n/a785

“ASK is now Convergence Networks!”

Source: company website · checked Sep 5, 2026
25
BitsightIndirect evidence
Boston, MA, United StatesHQ checked Sep 5, 2026501-1,000752

“Bitsight is the global leader in cyber risk intelligence, leveraging advanced AI to empower organizations with precise insights derived from the industry’s most extensive external…”

Source: company website · checked Sep 5, 2026

Showing 25 of 6,554 managed security service providers based in the United States

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Managed security service providers based in the United States at a glance

As of Sep 5, 2026
1-10Median size (employees)
New YorkLargest hub · 200 HQs
58,463Contacts with mobile numbers
Sep 5, 2026Data refreshed

Companies by employee count

1-10
3,538
11-50
2,123
51-200
629
201-500
131
501-1,000
53
1,001-5,000
47
5,001-10,000
7
10001+
12

Verified emails by last verification

0–30
80,106
31–60
5,323
61–90
83
90–180
52
180+
759

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 service providers, so some rows will be adjacent to the category rather than pure plays. The description and evidence 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 SmartSearch, 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 service providers”. Matching reads each company's description, not its industry code or its name.
What we exclude
Companies whose own description does not clearly place them among managed security service providers, 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 an evidence 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, 86,323 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 5, 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.

Managed security service providers by metro

Frequently asked

How many managed security service providers are there based in the United States?

RevenueBase identified 6,554 managed security service providers 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 managed security service providers?

New York leads with 200 headquartered companies, followed by Houston (120) and Austin (117).

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 86,323 verified decision-maker contacts tracked across these 6,554 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 5, 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.