Employment Tax

Belgium | BELSPO Directives 2025: updated notification rules for R&D wage withholding tax

Summary

For several years, the wage withholding tax regime for Research and Development (R&D) activities in Belgium has been regularly adjusted, evolving to a more harmonized application of the tax benefit and compliance with
legal requirements. As you may have heard, 2025 marks a new stage with substantial modifications introduced by BELSPO, this in coordination and agreement with the Belgian tax authorities.

The 2025 BELSPO update builds further on the insights from Circular 2023/C/49 and the 2024 directives, while incorporating clarifications and aiming to enhance legal clarity and security for companies declaring R&D projects in this context.

The detail

Mandatory prior registration and non bis in idem

• Since August 1, 2023 (Circular 2023/C/49), it has been mandatory for any R&D project or program to be registered before its launch to qualify for the wage withholding tax exemption.
• This formalistic requirement (to register projects/programs upfront) is still present in the 2025 guidelines, with an important clarification, notably a project or program can only be registered once!

*Copies or annual re-registrations are no longer accepted, except in cases of significant, duly justified adjustments.

*Updates to existing registrations remain possible, but the registration of projects or programs with minor modifications will be regarded as “repetition” and cannot lead to a new tax exemption.

Comparison with 2024 directives

• In 2024, the ban on annual re-registrations was already in effect, but companies still had the option to adjust their files progressively.
• In 2025, the rule becomes stricter: any registration must be accompanied by solid justifications, or it will be excluded.

Clear and descriptive titles mandatory for projects

• Project identification must be more precise: generic or meaningless titles like “ProjectX07” or “Program 99” are no longer accepted.
• This requirement aims to ensure better distinction, traceability of submitted projects and programs and to prevent vague or ambiguous declarations.

Comparison with 2024 directives

• In 2024, this rule was already recommended, but its enforcement was more flexible.
• In 2025, it becomes mandatory, requiring companies to specify the content of the project in the title itself.

Clear distinction between “registrations” and “advisory requests”

• Project/program registration is mandatory and forms the basis for benefiting from the withholding tax exemption.
• The advisory request, however, remains optional. However, it is now structured into two distinct parts:

*Project/program qualification: Verification that the project/program falls within the scope of fundamental research, industrial research, or experimental development.
*Researcher qualification: Validation of the diploma/degrees and competencies of the researchers involved.

• A project or program will no longer be considered innovative if it merely replicates elements already developed by other companies. This mention is remarkable and immediately gives rise to practical considerations and questions.

Comparison with 2024 directives

• In 2024, the advisory request was often confused with a registration, leading to inconsistencies in declarations.
• In 2025, the distinction is more clear and the advisory process becomes more detailed.

Mandatory proof of modifications and increased controls

• Companies must keep dated proof of each modification made to a registered project or program.
• During tax audits, companies must demonstrate that each update was justified and necessary.
• Stricter monitoring is announced to prevent any artificial extension of project durations.

Comparison with 2024 directives

• In 2024, traceability of modifications was encouraged, but controls were less stringent.
• In 2025, this obligation becomes systematic and could lead to penalties in case of non-compliance.

Separation of tax regimes: “wage withholding tax” vs. “innovation deduction”

• Until 2024, it was possible to submit a single advisory request covering both the R&D wage withholding tax exemption and the innovation deduction.
• In 2025, these two regimes are treated separated:

*A specific request is required for each measure.
*However, advisory opinions obtained within the framework of the wage withholding tax exemption may be reused for the innovation deduction.

Key takeaways

The BELSPO 2025 guidelines clearly introduce stricter rules, with the goal of increasing clarity and transparency. Registration becomes a more rigorous process, excluding any abusive re-registration and requiring a more structured follow-up of projects.

Companies must therefore anticipate their declarations, ensure compliance with title and description requirements, and document any project developments. Adhering to these new obligations will determine eligibility for tax benefits and necessitate more rigorous administrative management.

Contact us

For a deeper discussion on the above, please reach out to your Vialto Partners point of contact, or alternatively:

Anton Scornea
Manager

Filip Van Praet
Director

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