Company lists · Data refreshed September 2026
Top 25 Investigation firms worldwide
RevenueBase identified 9,839 investigation firms worldwide as of September 2026 and tracks 87,305 professional contacts across them, including 17,881 with verified work emails. The United States is the largest market and London the largest hub.
This list covers investigation firms 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 20, 2026. Country and city lists for investigation firms 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.
The 25 largest investigation firms worldwide
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 3,592 contacts → | ||||
Indirect evidence “U.S.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 2 | 1,233 contacts → | ||||
Strong evidence “BANQUE POPULAIRE BOURGOGNE FRANCHE-COM is a Security and Investigations company located in 14 BOULEVARD DE LA TREMOUILLE, DIJON, Burgundy, France.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 3 | 1,230 contacts → | ||||
Strong evidence “Cellebrite is the leader in digital intelligence and investigative analytics, partnering with public and private organizations to transform how they manage data in investigations…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 4 | 1,129 contacts → | ||||
Strong evidence “HKA is the leading global consultancy in risk mitigation, forensic investigations, dispute resolution, expert witness and litigation support services.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 5 | 748 contacts → | ||||
Indirect evidence “EFI Global is a multidisciplinary consulting firm that helps clients investigate, assess and resolve complex property, infrastructure and financial challenges.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 6 | 677 contacts → | ||||
Strong evidence “OMNIPLEX World Services Corporation is a leader and innovator in delivering professional background investigations, intelligence support, and physical security services to…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 7 | 626 contacts → | ||||
Strong evidence “Professional Security Consultants, Inc.(PSC) is a world-class provider of security guard services, patrol, investigations, backgrounds, consulting, security screening & specialty…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 8 | 572 contacts → | ||||
Strong evidence “DK Security is unique in that it offers a single company for a wide ranging availability of security and investigative services.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 9 | 518 contacts → | ||||
Strong evidence “CoventBridge Group is the leading worldwide full service investigation solutions company providing: Surveillance, SIU and Compliance, Claims Investigation, Counter-Fraud Programs…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 10 | 511 contacts → | ||||
Strong evidence “Founded in 1982, Ranger American is a professional security organization with an extensive background in the security and investigation fields.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 11 | 480 contacts → | ||||
Strong evidence “Engineering Systems Inc.(ESi) is a forensic engineering and scientific investigation firm committed to providing actionable solutions to industry and technical challenges through…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 12 | 404 contacts → | ||||
Strong evidence “American Security & Investigations has provided security and investigative services throughout the upper midwest since 1959.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 13 | 394 contacts → | ||||
Indirect evidence “Eurofins Forensic Services (formerly LGC Forensics) is the market leader in the provision of forensic services to the England and Wales Criminal Justice System and to criminal…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 14 | 383 contacts → | ||||
Indirect evidence “Founded in 1933, MDD is a leading international forensic accounting firm that provides economic damage quantification assessments for its clients.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 15 | 376 contacts → | ||||
Indirect evidence “Envista Forensics is the global leader in providing comprehensive forensic consulting and engineering services.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 16 | 373 contacts → | ||||
Indirect evidence “Ethos Risk Services is a technology-backed, full-service claims management company.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 17 | 340 contacts → | ||||
Indirect evidence “A full-service firm with the proven capabilities to manage all facets of your company’s security requirements, Norred & Associates, Inc.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 18 | 336 contacts → | ||||
Strong evidence “Vcheck is a global investigations firm that helps institutions protect their investments by providing intelligence on individuals and entities.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 19 | 330 contacts → | ||||
Strong evidence “Phangela Group is a premier security and investigations company headquartered in South Africa.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 20 | 327 contacts → | ||||
Strong evidence “DigiStream Investigations is a full-service private investigation firm specializing in insurance defense and legal support services.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 21 | 309 contacts → | ||||
Indirect evidence “Colvill Banks are experts in candidate research and identification.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 22 | 297 contacts → | ||||
Strong evidence “Established in 1970, S-E-A is a recognized worldwide leader in forensic analysis and investigation.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 23 | 292 contacts → | ||||
Strong evidence “HUB Enterprises is a national insurance defense investigative firm.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 24 | 268 contacts → | ||||
Indirect evidence “We stand at the forefront of leadership, insight, and guidance in a world marked by complexity and uncertainty.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 25 | 264 contacts → | ||||
Indirect evidence “iCOVER Group provides high-quality Third-Party Background Screening, Monitoring, and Due Diligence services.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
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: investigation firms. 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 investigation firms.
- Partial evidence
- Its own public description names part of investigation firms, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name investigation firms. 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 9,839 investigation firms worldwide
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Investigation firms worldwide at a glance
As of Sep 20, 2026Companies by employee count
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 investigation firms, 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 investigation firms are linked below.
- What qualifies
- Companies worldwide whose own description of what they do matches “investigation firms”. 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 investigation firms), 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 investigation firms, 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, 17,881 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 20, 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.
Investigation firms by location
38 lists · largest firstEvery Investigation firms list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.
Countries
- Investigation firms based in the United States4,013
- Investigation firms based in the United Kingdom687
- Investigation firms based in India411
- Investigation firms based in Italy379
- Investigation firms based in Canada333
- Investigation firms based in Brazil319
- Investigation firms based in Spain253
- Investigation firms based in France245
- Investigation firms based in Australia226
- Investigation firms based in South Africa146
- Investigation firms based in the Netherlands140
- Investigation firms based in Germany120
- Investigation firms based in Mexico80
- Investigation firms based in Poland63
- Investigation firms based in Switzerland55
- Investigation firms based in New Zealand44
- Investigation firms based in Israel37
- Investigation firms based in Ireland29
- Investigation firms based in Hong Kong28
Cities
- Investigation firms based in New York, United States145
- Investigation firms based in Houston, United States74
- Investigation firms based in Chicago, United States65
- Investigation firms based in New Delhi, India64
- Investigation firms based in Los Angeles, United States61
- Investigation firms based in Miami, United States60
- Investigation firms based in Washington, United States48
- Investigation firms based in Dallas, United States46
- Investigation firms based in Atlanta, United States45
- Investigation firms based in Mumbai, India41
- Investigation firms based in Phoenix, United States37
- Investigation firms based in Denver, United States34
- Investigation firms based in Fort Lauderdale, United States31
- Investigation firms based in Tampa, United States31
- Investigation firms based in Boston, United States29
- Investigation firms based in San Diego, United States29
- Investigation firms based in Seattle, United States29
- Investigation firms based in Orlando, United States28
- Investigation firms based in Las Vegas, United States27
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 investigation firms, 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 investigation firms are there worldwide?
RevenueBase identified 9,839 investigation firms 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?
U.S. Security Associates, INC, headquartered in Roswell, tops this list with the largest team on record.
Which country has the most investigation firms?
The United States leads with 4,013 companies, followed by the United Kingdom (687) and India (411). Every investigation firms list by country and city is linked on this page.
Which city has the most investigation firms?
London leads with 220 headquartered companies, followed by New York (145) and Sao Paulo (100).
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 17,881 verified decision-maker contacts tracked across these 9,839 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 20, 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.