Company lists · Data refreshed September 2026

Top 25 Due diligence services companies worldwide

RevenueBase identified 536 due diligence services companies worldwide as of September 2026 and tracks 4,173 professional contacts across them, including 1,444 with verified work emails. The United States is the largest market and London the largest hub.

This list covers due diligence services companies 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 19, 2026. Country and city lists for due diligence services companies 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 19, 2026 86% judged on-target in blind review
536Companies
4,173Contacts tracked
1,444Verified emails
Explore this list → Free signup · no credit card · 500 free credits

The 25 largest due diligence services companies worldwide

Ranked by team size
Top 25 of 536 due diligence services companies worldwide, ranked by team size, largest first. Data refreshed Sep 19, 2026. RevenueBase Smart Search rates how each company's information relates to due diligence services 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.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Indirect evidenceHowell, NJ, United StatesHQ checked Sep 19, 2026n/a241 contacts →

Indirect evidence

“We know you work hard to get the best deal possible.”

Source: RevenueBase Database · checked Sep 19, 2026
2Indirect evidenceTampa, FL, United StatesHQ checked Sep 19, 202651-200181 contacts →

Indirect evidence

“Maximizing Value.”

Source: RevenueBase Database · checked Sep 19, 2026
3Strong evidenceLondon, United KingdomHQ checked Sep 19, 202651-200159 contacts →

Strong evidence

“By leveraging cutting-edge technology and experienced analysts, Neotas are going beyond and setting new standards in Due Diligence, Staff Screening, and Compliance.”

Source: RevenueBase Database · checked Sep 19, 2026
4Strong evidenceParis, FranceHQ checked Sep 19, 202651-200101 contacts →

Strong evidence

“Exelmans est un Cabinet de conseil et d’audit spécialisé dans la due diligence financière.”

Source: RevenueBase Database · checked Sep 19, 2026
5Strong evidenceGold River, CA, United StatesHQ checked Sep 19, 202651-20077 contacts →

Strong evidence

“CREtelligent’s Radius Platform is the world's first 24/7 "CRE Due Diligence Storefront." CREtelligent provides almost every due diligence service CRE buyers, lenders and sellers…”

Source: RevenueBase Database · checked Sep 19, 2026
6Strong evidenceNew York, NY, United StatesHQ checked Sep 19, 202651-20075 contacts →

Strong evidence

“Blue Heron Research Partners is an international leader in qualitative due diligence.”

Source: RevenueBase Database · checked Sep 19, 2026
7Indirect evidenceMoorestown, NJ, United StatesHQ checked Sep 19, 202651-20068 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 19, 2026
8Strong evidenceMedford, OR, United StatesHQ checked Sep 19, 202611-5067 contacts →

Strong evidence

“Ashland Partners & Company LLP is a PCAOB registered, specialty CPA firm providing due diligence solutions to the investment management industry.”

Source: RevenueBase Database · checked Sep 19, 2026
9Indirect evidenceCincinnati, OH, United StatesHQ checked Sep 19, 202611-5062 contacts →

Indirect evidence

“Live investigator-led analysis is the best way to minimize regulatory, reputational and financial risks.”

Source: RevenueBase Database · checked Sep 19, 2026
10Strong evidenceHyderabad, IndiaHQ checked Sep 19, 202611-5058 contacts →

Strong evidence

Due Diligence AI that runs comprehensive financial, legal, regulatory and reputational risk analysis on any given target.”

Source: RevenueBase Database · checked Sep 19, 2026
11Strong evidenceSanta Monica, CA, United StatesHQ checked Sep 19, 202651-20049 contacts →

Strong evidence

“Ironsides is an M&A advisory firm focused exclusively on providing transaction services including financial and accounting due diligence, tax due diligence and structuring…”

Source: RevenueBase Database · checked Sep 19, 2026
12Indirect evidenceHong KongHQ checked Sep 19, 202651-20048 contacts →

Indirect evidence

“Blackpeak is dedicated to uncovering critical risks for our clients worldwide.”

Source: RevenueBase Database · checked Sep 19, 2026
13Strong evidenceAmsterdam, NetherlandsHQ checked Sep 19, 202611-5047 contacts →

Strong evidence

“SINCERIUS is frontrunner in data-driven due diligence.”

Source: RevenueBase Database · checked Sep 19, 2026
14Strong evidenceLondon, United KingdomHQ checked Sep 19, 202651-20047 contacts →

Strong evidence

“We empower private equity firms to make sound investment decisions with our award-winning digital due diligence, whilst supporting portfolio companies through necessary digital…”

Source: RevenueBase Database · checked Sep 19, 2026
15Strong evidenceLos Angeles, CA, United StatesHQ checked Sep 19, 20261,001-5,00047 contacts →

Strong evidence

“On the leading edge of innovation in commercial real estate transactions, GRS an NV5 Company is one of the largest national provider CRE due diligence services.”

Source: RevenueBase Database · checked Sep 19, 2026
16Strong evidenceCanton, OH, United StatesHQ checked Sep 19, 202651-20042 contacts →

Strong evidence

“Established in 1973, as Bock & Clark, NV5 Real Estate Transaction Services is the leading provider of commercial real estate due diligence services including ALTA Surveys, Zoning…”

Source: RevenueBase Database · checked Sep 19, 2026
17Strong evidenceNew York, NY, United StatesHQ checked Sep 19, 202651-20042 contacts →

Strong evidence

“Hilton Global Associates is a professional investigative research firm providing expert due diligence and unparalleled client service.”

Source: RevenueBase Database · checked Sep 19, 2026
18Strong evidenceHong KongHQ checked Sep 19, 202651-20039 contacts →

Strong evidence

“The Search Group (TSG) specializes in due diligence and business intelligence.”

Source: RevenueBase Database · checked Sep 19, 2026
19Indirect evidenceUnited StatesHQ checked Sep 19, 202651-20038 contacts →

Indirect evidence

“We provide real results, real quick.”

Source: RevenueBase Database · checked Sep 19, 2026
20Strong evidenceBoston, MA, United StatesHQ checked Sep 19, 202611-5037 contacts →

Strong evidence

“Fairmont Consulting Group is a Boston-based firm focused on due diligence and strategic advisory services for clients active in aerospace, defense, government services, and the…”

Source: RevenueBase Database · checked Sep 19, 2026
21Indirect evidenceSan Francisco, CA, United StatesHQ checked Sep 19, 202611-5037 contacts →

Indirect evidence

“CDS is now part of CrossCountry Consulting.”

Source: RevenueBase Database · checked Sep 19, 2026
22Indirect evidenceVienna, VA, United StatesHQ checked Sep 19, 202611-5033 contacts →

Indirect evidence

“Pipaya has joined Prosperity Partners!”

Source: RevenueBase Database · checked Sep 19, 2026
23Strong evidenceUnited StatesHQ checked Sep 19, 202611-5032 contacts →

Strong evidence

“Providing mortgage review and due diligence services”

Source: RevenueBase Database · checked Sep 19, 2026
24Strong evidenceColumbia, MD, United StatesHQ checked Sep 19, 202611-5027 contacts →

Strong evidence

“Our law firm combines highly specialized legal expertise with business and financial acumen, which allows us to provide our clients with focused intelligence and due diligence on…”

Source: RevenueBase Database · checked Sep 19, 2026
25Strong evidenceLondon, United KingdomHQ checked Sep 19, 202611-5024 contacts →

Strong evidence

“Connell Consulting has a reputation for carrying out reliable and well-researched commercial due diligence, strategic and operational improvement projects, delivered by a…”

Source: RevenueBase Database · checked Sep 19, 2026

Showing 25 of 536 due diligence services companies worldwide

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 1,444 reachable decision-makers.

Free signup · no credit card

View the full list →

Due diligence services companies worldwide at a glance

As of Sep 19, 2026
34.6%Verified-email coverage
7.8Average contacts per company
1-10Median size (employees)
4.7%Largest-city concentration · London
Sep 19, 2026Page data refreshed

Companies by employee count

1-10
359
11-50
138
51-200
33
201-500
3
1,001-5,000
2

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 due diligence services 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.
Coverage
Every country. Country and city lists for due diligence services companies are linked below.
What qualifies
Companies worldwide whose own description of what they do matches “due diligence services 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 due diligence services 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 due diligence services companies, 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, 1,444 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 19, 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.

Due diligence services companies by location

2 lists · largest first

Every Due diligence services companies list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.

Countries

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 due diligence services 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 due diligence services companies are there worldwide?

RevenueBase identified 536 due diligence services companies 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?

Gparency, headquartered in Howell, tops this list with the largest team on record.

Which country has the most due diligence services companies?

The United States leads with 194 companies, followed by the United Kingdom (33). Every due diligence services companies list by country and city is linked on this page.

Which city has the most due diligence services companies?

London leads with 25 headquartered companies, followed by New York (22) and Sao Paulo (10).

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 1,444 verified decision-maker contacts tracked across these 536 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 19, 2026.

Ready to reach these companies? Verified emails and direct dials for all 536 due diligence services companies worldwide. Start with a free account, no credit card.

Download this list →

Related lists

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.