Company lists · Data refreshed September 2026
Top 25 Investigation firms based in the United States
RevenueBase identified 4,013 investigation firms headquartered in the United States as of September 2026 and tracks 43,349 professional contacts across them, including 11,857 with verified work emails. New York is the largest hub.
This list covers investigation firms 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 20, 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.
The 25 largest investigation firms based in the United States
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 | 1,230 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. | |||||
| 3 | 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. | |||||
| 4 | 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. | |||||
| 5 | 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. | |||||
| 6 | 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. | |||||
| 7 | 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. | |||||
| 8 | 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. | |||||
| 9 | 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. | |||||
| 10 | 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. | |||||
| 11 | 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. | |||||
| 12 | 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. | |||||
| 13 | 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. | |||||
| 14 | 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. | |||||
| 15 | 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. | |||||
| 16 | 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. | |||||
| 17 | 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. | |||||
| 18 | 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. | |||||
| 19 | 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. | |||||
| 20 | 252 contacts → | ||||
Strong evidence “ADC supports government and corporate clients with two primary services - personnel security, ranging from pre-employment checks to comprehensive background investigations and…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 21 | 232 contacts → | ||||
Strong evidence “Founded in 1998, Resolution Economics provides sophisticated economic, statistical, and financial analyses, forensic investigations, forensic technology, dispute advisory, expert…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 22 | 230 contacts → | ||||
Indirect evidence “A national portfolio of premier forensic services companies, Aperture uses proven science and accepted industry standards to deliver accurate and efficient expert analysis.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 23 | 216 contacts → | ||||
Strong evidence “T&M USA provides seamlessly integrated executive protection, investigative and consulting services.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 24 | 214 contacts → | ||||
Indirect evidence “Frasco has hundreds of investigators and regional offices located throughout the country.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 25 | 214 contacts → | ||||
Strong evidence “Advantage Investigations is a nationwide leader in the industry for investigative 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 4,013 investigation firms based in the United States
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Investigation firms based in the United States at a glance
As of Sep 20, 2026Companies by employee count
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 4,013 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 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.
- What qualifies
- Companies headquartered in the United States 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. 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, 11,857 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 metro
- Investigation firms in New York145
- Investigation firms in Houston74
- Investigation firms in Chicago65
- Investigation firms in Los Angeles61
- Investigation firms in Miami60
- Investigation firms in Washington48
- Investigation firms in Dallas46
- Investigation firms in Atlanta45
- Investigation firms in Phoenix37
- Investigation firms in Denver34
- Investigation firms in Fort Lauderdale31
- Investigation firms in Tampa31
- Investigation firms in Boston29
- Investigation firms in San Diego29
- Investigation firms in Seattle29
- Investigation firms in Orlando28
- Investigation firms in Las Vegas27
- Investigation firms in Austin25
- Investigation firms in Nashville25
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 based in the United States?
RevenueBase identified 4,013 investigation firms 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?
U.S. Security Associates, INC, headquartered in Roswell, tops this list with the largest team on record.
Which city has the most investigation firms?
New York leads with 145 headquartered companies, followed by Houston (74) and Chicago (65).
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 11,857 verified decision-maker contacts tracked across these 4,013 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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Investigation firms by geography
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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.
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