Company lists · Data refreshed September 2026

Top 25 Investigative research firms based in the United States

Name: Investigative research firms 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 1,750 companies tracked

RevenueBase identified 1,750 investigative research firms headquartered in the United States as of September 2026 and tracks 15,055 professional contacts across them, including 4,559 with verified work emails. New York is the largest hub.

This list covers investigative research 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.

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

1,750Companies

15,055Contacts tracked

4,559Verified emails

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The 25 largest investigative research firms based in the United States

Ranked by team size

Top 25 of 1,750 investigative research firms 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 investigative research firms: 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	Vcheck	Partial evidence	New York, NY, United StatesHQ checked Sep 20, 2026	201-500	336 contacts →
	Partial 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, 2026
5	Digistream Investigations	Partial evidence	Davis, CA, United StatesHQ checked Sep 20, 2026	201-500	327 contacts →
	Partial 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
6	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
7	Guidepost Solutions	Indirect evidence	New York, NY, United StatesHQ checked Sep 20, 2026	201-500	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, 2026
8	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
9	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
10	Alpine Intel	Indirect evidence	Charlotte, NC, United StatesHQ checked Sep 20, 2026	1,001-5,000	203 contacts →
	Indirect evidence “Alpine Intel is dedicated to innovation across the property, auto, liability, and workers' comp insurance fields-helping our customers reach peak performance throughout the policy…” Source: RevenueBase Database · checked Sep 20, 2026
11	Quadrant Strategies	Indirect evidence	Washington, DC, United StatesHQ checked Sep 20, 2026	51-200	179 contacts →
	Indirect evidence “Quadrant Strategies helps the world’s most prominent companies navigate their most important brand, reputation, and product challenges.” Source: RevenueBase Database · checked Sep 20, 2026
12	Promark Research Corporation	Partial evidence	Spring, TX, United StatesHQ checked Sep 20, 2026	51-200	152 contacts →
	Partial evidence “Promark Research Corporation is headquartered in Spring, Texas, a few miles North of Houston.” Source: RevenueBase Database · checked Sep 20, 2026
13	Cleveland Research Company	Partial evidence	Cleveland, OH, United StatesHQ checked Sep 20, 2026	51-200	151 contacts →
	Partial evidence “Cleveland Research Company is an independent research firm headquartered in Cleveland, Ohio.” Source: RevenueBase Database · checked Sep 20, 2026
14	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
15	PSA	Partial evidence	Washington, DC, United StatesHQ checked Sep 20, 2026	51-200	142 contacts →
	Partial evidence “PSA is a global due diligence and investigations firm headquartered in Washington, DC.” Source: RevenueBase Database · checked Sep 20, 2026
16	Trendsource, INC	Indirect evidence	San Diego, CA, United StatesHQ checked Sep 20, 2026	11-50	141 contacts →
	Indirect evidence “TrendSource helps businesses document and measure compliance across employment, consumer reporting, government, finance, health care, and retail.” Source: RevenueBase Database · checked Sep 20, 2026
17	Beau Dietl & Associates	Partial evidence	New York, NY, United StatesHQ checked Sep 20, 2026	51-200	129 contacts →
	Partial 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
18	Lemieux & Associates	Indirect evidence	North Haven, CT, United StatesHQ checked Sep 20, 2026	501-1,000	119 contacts →
	Indirect 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
19	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
20	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
21	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
22	Gryphon	Indirect evidence	White Plains, NY, United StatesHQ checked Sep 20, 2026	51-200	96 contacts →
	Indirect evidence “Gryphon partners with clients across the globe to help them assess new opportunities and tackle their most complex problems often in challenging and opaque markets.” Source: RevenueBase Database · checked Sep 20, 2026
23	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
24	Rosettistarr	Partial evidence	Bethesda, MD, United StatesHQ checked Sep 20, 2026	51-200	93 contacts →
	Partial evidence “RosettiStarr provides cutting-edge intelligence, investigations, corporate risk and cyber security services to management teams, attorneys and investors worldwide.” Source: RevenueBase Database · checked Sep 20, 2026
25	Davis Research	Partial evidence	Calabasas, CA, United StatesHQ checked Sep 20, 2026	51-200	85 contacts →
	Partial evidence “Davis Research is a privately held family business that has been executing projects for market research professionals since 1970.” 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: investigative research 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 investigative research firms.
Partial evidence: Its own public description names part of investigative research firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name investigative research 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 1,750 investigative research firms based in the United States

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Investigative research firms based in the United States at a glance

As of Sep 20, 2026

30.3%Verified-email coverage

8.6Average contacts per company

1-10Median size (employees)

3.4%Largest-city concentration · New York

Sep 20, 2026Page data refreshed

Companies by employee count

1-10

1,173

11-50

430

51-200

100

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 1,750 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 investigative research 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 “investigative research 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 investigative research 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 investigative research 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, 4,559 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.

Investigative research firms 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 investigative research 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 investigative research firms are there based in the United States?

RevenueBase identified 1,750 investigative research 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?

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

Which city has the most investigative research firms?

New York leads with 59 headquartered companies, followed by Washington (28) and Houston (25).

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 4,559 verified decision-maker contacts tracked across these 1,750 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.