Company lists · Data refreshed September 2026

Top 25 Advisory and outsourcing services based in Belgium

RevenueBase identified 2,531 advisory and outsourcing services headquartered in Belgium as of September 2026 and tracks 43,402 professional contacts across them, including 12,977 with verified work emails and 1,523 with mobile numbers. Brussels is the largest hub.

This list covers advisory and outsourcing services headquartered in Belgium, 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 23, 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 23, 2026 86% judged on-target in blind review
2,531Companies
43,402Contacts tracked
12,977Verified emails
1,523Mobile numbers
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The 25 largest advisory and outsourcing services based in Belgium

Ranked by team size
Top 25 of 2,531 advisory and outsourcing services based in Belgium, ranked by team size, largest first. Data refreshed Sep 23, 2026. RevenueBase Smart Search rates how each company's information relates to advisory and outsourcing services: 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 evidenceBrussels, BelgiumHQ checked Sep 23, 202610001+14,003 contacts →

Indirect evidence

“BDO is the leading provider of professional services within the mid-tier of our profession.”

Source: RevenueBase Database · checked Sep 23, 2026
2Indirect evidenceKortrijk, BelgiumHQ checked Sep 23, 20261,001-5,0001,713 contacts →

Indirect evidence

“WHAT do we do?”

Source: RevenueBase Database · checked Sep 23, 2026
3Indirect evidenceBrussel - Bruxelles, BelgiumHQ checked Sep 23, 20261,001-5,0001,626 contacts →

Indirect evidence

“At Securex, we help you catch a breather.”

Source: RevenueBase Database · checked Sep 23, 2026
4Indirect evidenceZaventem, BelgiumHQ checked Sep 23, 20261,001-5,0001,592 contacts →

Indirect evidence

“Uncovering a world of opportunity together.”

Source: RevenueBase Database · checked Sep 23, 2026
5Indirect evidenceBrussels, BelgiumHQ checked Sep 23, 20261,001-5,0001,087 contacts →

Indirect evidence

“Moore Belgium is het grootste onafhankelijke accounting- en consulting bedrijf in België dat ondernemers helpt hun droom te realiseren.”

Source: RevenueBase Database · checked Sep 23, 2026
6Indirect evidenceZaventem, BelgiumHQ checked Sep 23, 20261,001-5,000936 contacts →

Indirect evidence

“At BDO, we believe in empowering organisations and people to achieve sustainable growth and realise their full potential.”

Source: RevenueBase Database · checked Sep 23, 2026
7Indirect evidenceGent, BelgiumHQ checked Sep 23, 2026501-1,000679 contacts →

Indirect evidence

“At Attentia, we always link our HR advice to well-being, protection, and prevention.”

Source: RevenueBase Database · checked Sep 23, 2026
8Indirect evidenceKortrijk, BelgiumHQ checked Sep 23, 2026501-1,000564 contacts →

Indirect evidence

“Vandelanotte, opgericht in 1948 door Roger Vandelanotte, is uitgegroeid tot het grootste onafhankelijke kantoor in België, met ook een vestiging in Rijsel (Frankrijk).”

Source: RevenueBase Database · checked Sep 23, 2026
9Indirect evidenceWemmel, BelgiumHQ checked Sep 23, 2026201-500559 contacts →

Indirect evidence

“Samen ondernemen, met kennis en visie.”

Source: RevenueBase Database · checked Sep 23, 2026
10Indirect evidenceLeuven, BelgiumHQ checked Sep 23, 2026501-1,000515 contacts →

Indirect evidence

“Welcome to SBB, a firm of experienced accountants and tax consultants with 30 branches in Belgium.”

Source: RevenueBase Database · checked Sep 23, 2026
11Indirect evidenceRoeselare, BelgiumHQ checked Sep 23, 2026201-500384 contacts →

Indirect evidence

“Titeca is not a traditional accounting firm.”

Source: RevenueBase Database · checked Sep 23, 2026
12Indirect evidenceKontich, BelgiumHQ checked Sep 23, 2026201-500341 contacts →

Indirect evidence

“Cheops is an industry-leading provider of IT & Business Technology Services.”

Source: RevenueBase Database · checked Sep 23, 2026
13Indirect evidenceGent, BelgiumHQ checked Sep 23, 2026201-500316 contacts →

Indirect evidence

“Dé adviseur voor de ambitieuze ondernemer.”

Source: RevenueBase Database · checked Sep 23, 2026
14Indirect evidenceKortrijk, BelgiumHQ checked Sep 23, 202651-200290 contacts →

Indirect evidence

“We are your guide on the adventure of entrepreneurship!”

Source: RevenueBase Database · checked Sep 23, 2026
15Indirect evidenceRoeselare, BelgiumHQ checked Sep 23, 2026201-500287 contacts →

Indirect evidence

“Iemand van AlliA herkent u meteen.”

Source: RevenueBase Database · checked Sep 23, 2026
16Indirect evidenceBrussels, BelgiumHQ checked Sep 23, 2026201-500274 contacts →

Indirect evidence

“Most organizations are facing major transformation challenges due to market, technological, social or political factors.”

Source: RevenueBase Database · checked Sep 23, 2026
17Indirect evidenceHasselt, BelgiumHQ checked Sep 23, 2026201-500272 contacts →

Indirect evidence

“UW RECHTERHAND Als ondernemer bent u maar zo sterk als de mensen die u omringen.”

Source: RevenueBase Database · checked Sep 23, 2026
18Indirect evidenceStrombeek-bever, BelgiumHQ checked Sep 23, 2026501-1,000242 contacts →

Indirect evidence

“Hi, we’re Tobania, your trusted partner in Business and Technology Consulting, driving the forefront of digital transformation by valorising your business, data and technology.”

Source: RevenueBase Database · checked Sep 23, 2026
19Partial evidenceBrussels, BelgiumHQ checked Sep 23, 2026201-500221 contacts →

Partial evidence

“Forvis Mazars provides audit, assurance, tax, advisory, and consulting services globally with a dedication to delivering an unmatched client experience.”

Source: RevenueBase Database · checked Sep 23, 2026
20Indirect evidenceBrussel, BelgiumHQ checked Sep 23, 2026201-500220 contacts →

Indirect evidence

“Bij Baker Tilly bouwen we mee aan het groeiverhaal van ondernemers.”

Source: RevenueBase Database · checked Sep 23, 2026
21Indirect evidenceWaregem, BelgiumHQ checked Sep 23, 2026201-500210 contacts →

Indirect evidence

“Our Talent.”

Source: RevenueBase Database · checked Sep 23, 2026
22Indirect evidenceBeaufays, BelgiumHQ checked Sep 23, 2026n/a198 contacts →

Indirect evidence

“Bonjour et bienvenue sur la page entreprise de la Fiduciaire au Carré - Une équipe dynamique à votre service- Assistance efficace et conseils individualisés tant aux personnes…”

Source: RevenueBase Database · checked Sep 23, 2026
23Indirect evidenceBrussels, BelgiumHQ checked Sep 23, 202651-200192 contacts →

Indirect evidence

“ABERDEEN Services is a consulting firm founded in 2012 by Alec BERNARD and Mathieu VERGER.”

Source: RevenueBase Database · checked Sep 23, 2026
24Indirect evidenceWilsele, BelgiumHQ checked Sep 23, 20261,001-5,000160 contacts →

Indirect evidence

“At Ausy, we’ve been providing technological solutions for over 30 years.”

Source: RevenueBase Database · checked Sep 23, 2026
25Indirect evidenceGent, BelgiumHQ checked Sep 23, 2026501-1,000130 contacts →

Indirect evidence

“Je professionele succes en je financiële zekerheid laat je liever niet aan het toeval over.”

Source: RevenueBase Database · checked Sep 23, 2026

Showing 25 of 2,531 advisory and outsourcing services based in Belgium

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Advisory and outsourcing services based in Belgium at a glance

As of Sep 23, 2026
29.9%Verified-email coverage
3.5%Mobile-number coverage
17.1Average contacts per company
1-10Median size (employees)
5.8%Largest-city concentration · Brussels
Sep 23, 2026Page data refreshed

Companies by employee count

1-10
1,974
11-50
396
51-200
103
201-500
27
501-1,000
12
1,001-5,000
10
10001+
2

Freshness & accuracy

How recently the business emails were verified and the company information checked

Email last verified

Median 25.0d

Company record updated

Median 77.0d

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 advisory and outsourcing services, 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 Belgium whose own description of what they do matches “advisory and outsourcing services”. 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 advisory and outsourcing services), 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 advisory and outsourcing services, and records with no verified work email. Companies headquartered outside Belgium 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, 12,977 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 23, 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.

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 advisory and outsourcing services, 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 advisory and outsourcing services are there based in Belgium?

RevenueBase identified 2,531 advisory and outsourcing services headquartered in Belgium 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?

BDO, headquartered in Zaventem, tops this list with the largest team on record.

Which city has the most advisory and outsourcing services?

Brussels leads with 148 headquartered companies, followed by Antwerpen (83) and Bruxelles (78).

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 12,977 verified decision-maker contacts tracked across these 2,531 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 23, 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.