Company lists · Data refreshed September 2026

Top 25 Private investigation companies based in the United States

Name: Private investigation companies based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 20, 2026 1,763 companies tracked

RevenueBase identified 1,763 private investigation companies headquartered in the United States as of September 2026 and tracks 11,903 professional contacts across them, including 2,853 with verified work emails. New York is the largest hub.

This list covers private investigation 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 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.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 20, 2026 86% judged on-target in blind review

1,763Companies

11,903Contacts tracked

2,853Verified emails

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The 25 largest private investigation companies based in the United States

Ranked by team size

Top 25 of 1,763 private investigation companies based in the United States, ranked by team size, largest first. Data refreshed Sep 20, 2026. RevenueBase Smart Search rates how each company's information relates to private investigation 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.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Omniplex World Services Corporation	Partial evidence	Herndon, VA, United StatesHQ checked Sep 20, 2026	1,001-5,000	677 contacts →
	Partial 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, 2026
2	DK Security	Partial evidence	Grand Rapids, MI, United StatesHQ checked Sep 20, 2026	1,001-5,000	572 contacts →
	Partial 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, 2026
3	Coventbridge Group	Partial evidence	Jacksonville, FL, United StatesHQ checked Sep 20, 2026	501-1,000	518 contacts →
	Partial 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, 2026
4	Digistream Investigations	Strong evidence	Davis, CA, United StatesHQ checked Sep 20, 2026	201-500	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, 2026
5	HUB Enterprises, INC	Partial evidence	Broussard, LA, United StatesHQ checked Sep 20, 2026	501-1,000	292 contacts →
	Partial evidence “HUB Enterprises is a national insurance defense investigative firm.” Source: RevenueBase Database · checked Sep 20, 2026
6	Frasco	Indirect evidence	Irvine, CA, United StatesHQ checked Sep 20, 2026	201-500	214 contacts →
	Indirect evidence “Frasco has hundreds of investigators and regional offices located throughout the country.” Source: RevenueBase Database · checked Sep 20, 2026
7	Advantage Investigations	Partial evidence	Kannapolis, NC, United StatesHQ checked Sep 20, 2026	201-500	214 contacts →
	Partial evidence “Advantage Investigations is a nationwide leader in the industry for investigative services.” Source: RevenueBase Database · checked Sep 20, 2026
8	Information Discovery Services LLC	Partial evidence	Fort Worth, TX, United StatesHQ checked Sep 20, 2026	51-200	146 contacts →
	Partial evidence “A federally qualified Small Business, IDS offers end to end investigative solutions tailored to meet the specific needs of our clients.” Source: RevenueBase Database · checked Sep 20, 2026
9	Beau Dietl & Associates	Strong evidence	New York, NY, United StatesHQ checked Sep 20, 2026	51-200	129 contacts →
	Strong evidence “Beau Dietl & Associates is a premier private investigation firm based in New York City with offices in New Jersey, Florida, and California.” Source: RevenueBase Database · checked Sep 20, 2026
10	Lemieux & Associates	Partial evidence	North Haven, CT, United StatesHQ checked Sep 20, 2026	501-1,000	119 contacts →
	Partial evidence “Knowledge is power" Whether you are an insurance company, TPA, insurance defense law firm, risk manager, private law firm, or corporation / business owner, we at Lemieux &…” Source: RevenueBase Database · checked Sep 20, 2026
11	Nardello & CO	Indirect evidence	New York, NY, United StatesHQ checked Sep 20, 2026	51-200	112 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 20, 2026
12	Alias Intelligence	Partial evidence	Los Angeles, TX, United StatesHQ checked Sep 20, 2026	51-200	107 contacts →
	Partial evidence “Alias Intelligence is a leading background investigations and due diligence company delivering the information and insights our clients need to grow and navigate their businesses.” Source: RevenueBase Database · checked Sep 20, 2026
13	The Robison Group	Partial evidence	Troy, MI, United StatesHQ checked Sep 20, 2026	201-500	104 contacts →
	Partial evidence “The Robison Group is an agency of professional investigators and support teams offering surveillance, SIU claims, business risk mitigation and comprehensive desktop investigation…” Source: RevenueBase Database · checked Sep 20, 2026
14	Becker & Company, INC	Indirect evidence	United StatesHQ checked Sep 20, 2026	201-500	94 contacts →
	Indirect evidence “Why Becker & Company?” Source: RevenueBase Database · checked Sep 20, 2026
15	Marshall Investigative Group LLC	Partial evidence	Park Ridge, IL, United StatesHQ checked Sep 20, 2026	201-500	84 contacts →
	Partial evidence “Marshall Investigative Group, division of Sphere Investigations, is a recognized leader in fraud and corporate investigations with more than 30 years of experience across North…” Source: RevenueBase Database · checked Sep 20, 2026
16	Horsemen Investigations	Partial evidence	Huntington Beach, CA, United StatesHQ checked Sep 20, 2026	51-200	84 contacts →
	Partial evidence “Horsemen Investigations is a full service investigation company, specializing in investigating insurance fraud and in minimizing risk exposure.” Source: RevenueBase Database · checked Sep 20, 2026
17	AJ Squared Security	Partial evidence	New York, NY, United StatesHQ checked Sep 20, 2026	201-500	82 contacts →
	Partial evidence “AJ Squared Security, Inc.(AJ2), is a privately owned security organization founded in May 2003 and incorporated in November 2003.” Source: RevenueBase Database · checked Sep 20, 2026
18	Integrated Security Services	Indirect evidence	New York, NY, United StatesHQ checked Sep 20, 2026	201-500	72 contacts →
	Indirect evidence “Integrated Security Services, Inc.” Source: RevenueBase Database · checked Sep 20, 2026
19	CSI Corporate Security And Investigations	Partial evidence	Monaca, PA, United StatesHQ checked Sep 20, 2026	201-500	69 contacts →
	Partial evidence “CSI is a full-service investigative firm that delivers key facts to give our clients an actionable advantage in a wide range of situations.” Source: RevenueBase Database · checked Sep 20, 2026
20	THURO	Indirect evidence	Cleveland, OH, United StatesHQ checked Sep 20, 2026	51-200	68 contacts →
	Indirect evidence “Hiring the right people isn’t just about checking a box-it’s about ensuring accuracy, mitigating risk, and protecting your organization.” Source: RevenueBase Database · checked Sep 20, 2026
21	Claims Bureau USA	Partial evidence	Woburn, MA, United StatesHQ checked Sep 20, 2026	201-500	67 contacts →
	Partial evidence “Claims Bureau USA has been providing Insurers, TPA's and their defense counsel with quality, in-depth investigative services since 1956.” Source: RevenueBase Database · checked Sep 20, 2026
22	Investigative Group International	Partial evidence	Washington, DC, United StatesHQ checked Sep 20, 2026	11-50	66 contacts →
	Partial evidence “Investigative Group International (IGI) is the premier investigative firm conducting independent, high-touch investigations worldwide.” Source: RevenueBase Database · checked Sep 20, 2026
23	Apex Investigation	Partial evidence	Sacramento, CA, United StatesHQ checked Sep 20, 2026	51-200	57 contacts →
	Partial evidence “Today’s professionals rely on investigative firms to help manage risk by detecting and preempting problem situations.” Source: RevenueBase Database · checked Sep 20, 2026
24	Roman & Associates	Partial evidence	Uniondale, NY, United StatesHQ checked Sep 20, 2026	51-200	55 contacts →
	Partial evidence “For over 30 years, Roman & Associates has been a prominent and full-service Investigations & Risk Management firm.” Source: RevenueBase Database · checked Sep 20, 2026
25	Stewart & Associates INC	Indirect evidence	Freeport, IL, United StatesHQ checked Sep 20, 2026	201-500	52 contacts →
	Indirect evidence “Stewart & Associates was founded in 1987 by Brian W.” Source: RevenueBase Database · checked Sep 20, 2026

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: private investigation companies. 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 private investigation companies.
Partial evidence: Its own public description names part of private investigation companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name private investigation companies. 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 1,763 private investigation companies based in the United States

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Private investigation companies based in the United States at a glance

As of Sep 20, 2026

24.0%Verified-email coverage

6.8Average contacts per company

1-10Median size (employees)

2.9%Largest-city concentration · New York

Sep 20, 2026Page data refreshed

Companies by employee count

1-10

1,212

11-50

401

51-200

105

201-500

501-1,000

1,001-5,000

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 1,763 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 private investigation 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 “private investigation 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 private investigation 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 private investigation 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, 2,853 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.

Private investigation companies by metro

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 private investigation 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 private investigation companies are there based in the United States?

RevenueBase identified 1,763 private investigation 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?

Omniplex World Services Corporation, headquartered in Herndon, tops this list with the largest team on record.

Which city has the most private investigation companies?

New York leads with 51 headquartered companies, followed by Houston (26) and Miami (26).

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 2,853 verified decision-maker contacts tracked across these 1,763 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.