Belgian Withholding Tax Exemption for R&D Staff

The question

You employ engineers, developers or scientists on research and development work. Belgian law lets the employer keep part of the professional withholding tax on their pay instead of paying it over to the State. Which of your people qualify, which of your projects, and what will the tax administration expect to see if it checks?

The exemption from payment of professional withholding tax for researchers is in article 275/3 of the Income Tax Code 1992 (WIB 92). For researchers who qualify, the employer may retain up to 80% of the withholding tax due on their remuneration. It is a cash-flow benefit that lowers the cost of the R&D team, and it applies in proportion to the time each person actually spends on the research.

Typical situations are a scale-up that hires its first research engineers and wants to know whether the exemption is available, a company that has claimed it for years and receives a request for information from the tax administration, and a group that restructures its teams and needs to know what happens to projects already registered.

Our approach

We begin with the project. The R&D programme or project must be registered with the Belgian Science Policy Office (BELSPO), and registration must come before the work starts: a project notified after it has begun risks falling outside the exemption. The R&D itself is defined by reference to fundamental research, industrial research and experimental development. Routine product work, quality control and standard engineering do not qualify unless they contain a real research element, and that boundary is where audits tend to focus.

Then we look at the people. Qualification depends on the person's diploma, with a master's degree or doctorate in a recognised scientific field as the core case. Bachelor-level staff can also qualify, but on a more limited basis, and the rules for staff without a qualifying diploma have been adjusted for research programmes recognised by BELSPO. We check each employee against the current conditions rather than assuming a role title decides it.

Then we set up the evidence. A claim stands or falls on four documents per project: a technical description showing the R&D character of the work, time records per employee that split research from other tasks, proof of diplomas, and payroll data that ties the exemption to actual salary. Through the client portal you and your payroll provider can supply and track these records alongside us, and our Document Studio helps us draft employment-contract clauses and project descriptions that match what is registered.

Finally, we coordinate. The exemption can be combined with R&D grants and the innovation income deduction, provided costs are not counted twice. The overview of Belgian grants and tax incentives shows how the pieces fit.

Note that the 2026 Programme Law is reported to introduce a limiting correction factor on this and similar withholding tax benefits from 1 January 2027. We confirm the current figures when we advise, because they affect the value of the benefit in your business case.

What you get

• A written assessment of which projects and employees qualify.
• Support with the BELSPO registration and the timing around it.
• A documentation set: project descriptions, time-recording method, diploma file and payroll reconciliation.
• A combined view with your other R&D incentives, so costs are allocated once.
• Support if the administration reviews the claim, including the preparation of the audit file.

A lawyer at Pitch reviews every position before it goes into a filing or payroll treatment.

Take a Mechelen company with twelve engineers, of whom seven work on a new sensor platform. Before the project starts we help register it with BELSPO and agree a time-recording method with the HR manager: a simple weekly allocation per person, signed off by the project lead. We check diplomas, exclude the two engineers whose work is maintenance, and give the payroll provider a note on how the exemption is to be calculated per employee. When the administration asks questions two years later, the file contains the registration, the project description, the time records and the diplomas, and the answer takes days instead of weeks of reconstruction.

Next step

Tell us about the research you run and who works on it, and we will say whether the exemption fits.

Schedule a meeting or contact us.