Company lists · Data refreshed September 2026

Top 25 Managed IT security services providers worldwide

RevenueBase identified 19,751 managed IT security services providers worldwide as of September 2026 and tracks 296,289 professional contacts across them, including 99,623 with verified work emails. The United States is the largest market and London the largest hub.

This list covers managed IT security services providers worldwide, 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. Country and city lists for managed IT security services providers follow the table.

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
19,751Companies
296,289Contacts tracked
99,623Verified emails
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The 25 largest managed IT security services providers worldwide

Ranked by team size
Top 25 of 19,751 managed IT security services providers worldwide, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to managed IT security services providers: 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
1Indirect evidenceUnited StatesHQ checked Sep 21, 2026n/a12,771 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 21, 2026
2Indirect evidenceAbingdon, United KingdomHQ checked Sep 21, 20265,001-10,0004,925 contacts →

Indirect evidence

“Sophos is a cybersecurity leader defending organizations globally with an AI-driven platform and expert-led services.”

Source: RevenueBase Database · checked Sep 21, 2026
3Partial evidenceBengaluru, IndiaHQ checked Sep 21, 20265,001-10,0004,328 contacts →

Partial evidence

“CMS IT is a leading India-focused, tier-1 preferred IT provider with a legacy of four decades.”

Source: RevenueBase Database · checked Sep 21, 2026
4Indirect 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
5Strong evidenceFoster City, CA, United StatesHQ checked Sep 21, 20261,001-5,0003,058 contacts →

Strong evidence

“Qualys, Inc.(NASDAQ: QLYS) is a leading provider of disruptive cloud-based security, compliance and IT solutions with more than subscription customers worldwide, including a…”

Source: RevenueBase Database · checked Sep 21, 2026
6Indirect 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
7Strong evidenceRockville, MD, United StatesHQ checked Sep 21, 2026n/a1,906 contacts →

Strong evidence

“Established in 1995, GURU is an IT managed service provider that specializes in infrastructure support, systems integration, data architecture, data hosting, and cloud services.”

Source: RevenueBase Database · checked Sep 21, 2026
8Partial evidenceHerndon, VA, United StatesHQ checked Sep 21, 20261,001-5,0001,749 contacts →

Partial evidence

“ePlus is a customer-first, services-led, results-driven and trusted industry leader that helps organizations secure, modernize, optimize, and scale every aspect of their IT…”

Source: RevenueBase Database · checked Sep 21, 2026
9Indirect evidenceMeudon La Foret, FranceHQ checked Sep 21, 2026n/a1,519 contacts →

Indirect evidence

“Société d'infogérance”

Source: RevenueBase Database · checked Sep 21, 2026
10Indirect evidenceMaidenhead, United KingdomHQ checked Sep 21, 20265,001-10,0001,372 contacts →

Indirect evidence

“We are Architects of Change™.”

Source: RevenueBase Database · checked Sep 21, 2026
11Partial 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
12Indirect evidenceSan Jose, CA, United StatesHQ checked Sep 21, 20261,001-5,0001,181 contacts →

Indirect evidence

“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: RevenueBase Database · checked Sep 21, 2026
13Indirect evidenceSeattle, WA, United StatesHQ checked Sep 21, 20261,001-5,0001,059 contacts →

Indirect evidence

“WatchGuard® Technologies, Inc.”

Source: RevenueBase Database · checked Sep 21, 2026
14Partial evidenceCosta Mesa, CA, United StatesHQ checked Sep 21, 20261,001-5,0001,037 contacts →

Partial evidence

“Synoptek is a leading global managed services provider and technology consulting firm that delivers transformative business results.”

Source: RevenueBase Database · checked Sep 21, 2026
15Indirect evidenceBaltimore, MD, United StatesHQ checked Sep 21, 2026501-1,000904 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 21, 2026
16Indirect evidenceSingaporeHQ checked Sep 21, 2026501-1,000888 contacts →

Indirect evidence

“Ensign InfoSecurity is the largest pure-play end-to-end cybersecurity service provider in Asia.”

Source: RevenueBase Database · checked Sep 21, 2026
17Indirect evidenceChicago, IL, United StatesHQ checked Sep 21, 2026501-1,000874 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
18Indirect evidenceKansas City, MO, United StatesHQ checked Sep 21, 20261,001-5,000844 contacts →

Indirect evidence

“Today’s threatscape is relentless.”

Source: RevenueBase Database · checked Sep 21, 2026
19Partial evidenceStaines-upon-thames, United KingdomHQ checked Sep 21, 2026201-500764 contacts →

Partial evidence

“MTI provides award-winning, end-to-end technology solutions and services in cyber security and data centre for over 35 years.”

Source: RevenueBase Database · checked Sep 21, 2026
20Strong evidenceMumbai, IndiaHQ checked Sep 21, 2026501-1,000763 contacts →

Strong evidence

“With 35 years of experience, Softcell Technologies Global is a trusted IT services provider specialising in (i) IT security and cybersecurity solutions,(ii) cloud / on-premise…”

Source: RevenueBase Database · checked Sep 21, 2026
21Strong evidenceLisbon, PortugalHQ checked Sep 21, 20261,001-5,000753 contacts →

Strong evidence

“Claranet Portugal is the Portuguese market leader in Information Technologies and a specialist in Cloud, Workplace, Applications, Data & AI and Security solutions and managed…”

Source: RevenueBase Database · checked Sep 21, 2026
22Indirect evidenceAustin, TX, United StatesHQ checked Sep 21, 20261,001-5,000751 contacts →

Indirect evidence

“TPx is the reliable sidekick every growing business deserves, powering your tech while you take the lead.”

Source: RevenueBase Database · checked Sep 21, 2026
23Partial evidenceNorwalk, CT, United StatesHQ checked Sep 21, 20261,001-5,000731 contacts →

Partial evidence

“As a leading global provider of security and cloud-based software solutions purpose-built for MSPs, Datto, a Kaseya company, believes there is no limit to what SMBs can achieve…”

Source: RevenueBase Database · checked Sep 21, 2026
24Indirect evidenceColumbia, MD, United StatesHQ checked Sep 21, 2026501-1,000696 contacts →

Indirect evidence

“Protect Your Endpoints, Identities, Logs, and Employees.”

Source: RevenueBase Database · checked Sep 21, 2026
25Indirect evidenceMünchen, GermanyHQ checked Sep 21, 2026501-1,000692 contacts →

Indirect evidence

“Identity Excellence Delivered.”

Source: RevenueBase Database · checked Sep 21, 2026

Showing 25 of 19,751 managed IT security services providers worldwide

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Managed IT security services providers worldwide at a glance

As of Sep 21, 2026
33.6%Verified-email coverage
15.0Average contacts per company
1-10Median size (employees)
2.1%Largest-city concentration · London
Sep 21, 2026Page data refreshed

Companies by employee count

1-10
10,725
11-50
6,739
51-200
1,664
201-500
363
501-1,000
114
1,001-5,000
81
5,001-10,000
11
10001+
8

Email recency is reported on each country list linked below.

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 IT security services providers, 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.
Coverage
Every country. Country and city lists for managed IT security services providers are linked below.
What qualifies
Companies worldwide whose own description of what they do matches “managed IT security services providers”. 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 IT security services providers), 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 IT security services providers, and records with no verified work email.
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, 99,623 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.

Managed IT security services providers by location

101 lists · largest first

Every Managed IT security services providers list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.

Countries

Cities

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 IT security services providers, 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 IT security services providers are there worldwide?

RevenueBase identified 19,751 managed IT security services providers worldwide 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?

Private Sector, headquartered in Worldwide, tops this list with the largest team on record.

Which country has the most managed IT security services providers?

The United States leads with 6,736 companies, followed by the United Kingdom (1,458) and India (1,157). Every managed IT security services providers list by country and city is linked on this page.

Which city has the most managed IT security services providers?

London leads with 408 headquartered companies, followed by New York (198) and Toronto (171).

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 99,623 verified decision-maker contacts tracked across these 19,751 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.