DEADLINE · 3 OCTOBER 2026 · EMPLOYERS

WBSO deadline 20 December 2026: applying for a 1 January 2027 start

Want to use the WBSO from 1 January 2027? For companies with staff, the WBSO application must be submitted by 20 December 2026 at the latest — earlier than the usual monthly cut-off. Important: 20 December 2026 falls on a Sunday and the RVO helpdesk is not available at weekends.

Why is 20 December important?

Normally, employers can apply for WBSO up to and including the last day of a month for an application period starting on the first day of the following month. For 1 January there is one important exception: if you want your WBSO period to commence on 1 January, the application must already be submitted to RVO by 20 December of the preceding year. RVO lists this exception both in the WBSO calendar and in the conditions of the scheme.

What happens if you apply after 20 December?

If, as an employer, you submit your application after 20 December, your application period can no longer start on 1 January. Because WBSO can only be granted for future activities, you cannot bring the missed part of January under the WBSO afterwards — WBSO cannot be applied for retroactively. So if you want R&D hours to fall under the WBSO from the start of 2027, filing on time is essential.

Don't wait until 20 December to submit your application

Although 20 December is the formal deadline, we advise finishing the substantive preparation earlier. A good WBSO application is not just a matter of filling in a form. For every project it must be clear:

• what you intend to develop technically;
• which technical bottlenecks exist;
• why existing knowledge or techniques do not directly suffice;
• which new technical approaches you will investigate or develop yourself;
• which activities your own employees carry out and how many R&D hours you expect;
• which costs and expenses — where applicable — are connected to the R&D project.

Moreover, 20 December 2026 falls on a Sunday. If questions arise during the final check about the RVO portal, eHerkenning (Dutch e-ID for businesses), a chain mandate or the content of the application, the RVO helpdesk cannot be reached that day. Practical advice: aim to file by Friday 18 December 2026.

Does an existing WBSO project continue into 2027?

Even if you already hold an R&D declaration for 2026, it does not automatically continue into 2027. A WBSO application runs until 31 December of the calendar year at the latest. Projects that continue into the next calendar year must therefore be included again in a WBSO application for the following year. If you want to continue without interruption from 1 January, employers must also meet the 20 December 2026 deadline.

New projects for 2027

The December application is also a good moment to reassess your technical development portfolio. Multiple R&D projects can be included in one WBSO application; for the first application of the calendar year, RVO advises including all projects for which you expect employees to carry out R&D activities that year — from new products, production processes and prototypes to software and new technical challenges arising within existing projects.

WBSO will become more attractive in some respects in 2027

Under the announced plans, the main percentages remain unchanged for 2027: 36% in the first bracket, 50% for starters in the first bracket and 16% above the threshold, which stays at €391,020. In addition, the fixed R&D hourly rate will rise from €29 to €33 — this will particularly benefit companies without a calculated historical R&D hourly rate. More on this: WBSO 2027 – changes, rates and conditions → WBSO hourly rate 2027 rises to €33 →

Is the deadline different for freelancers?

Yes. The 20 December 2026 deadline is specifically relevant to S&O withholding entities: companies with staff. For self-employed people without staff, different application terms apply; their application period generally starts on the filing date. Do you have a sole proprietorship in which you both carry out R&D yourself and employ staff? Then both regimes can apply side by side.

What needs to be arranged before 20 December?

• Which projects continue? Identify which 2026 WBSO projects carry on into 2027.
• Which new projects start? Assess new technical developments and lines of technical research.
• What are the technical bottlenecks? The application must make clear which concrete technical problems you expect to solve.
• Which activities do you carry out yourself? Only R&D activities carried out by the applicant or the applicant's own employees can be included.
• How many hours do you expect? Make a realistic estimate of R&D hours up to and including 31 December 2027.
• Which costs and expenses do you expect? If you do not use the fixed allowance for costs and expenses, relevant costs must be carefully budgeted and applied for in advance.

Start the 2027 WBSO application in good time

December may seem far away, but with technically complex projects most of the time is not spent filing the application — the quality lies in the preparation. It is precisely the description of the technical development goal, the bottlenecks and your own solution directions that determines whether RVO can properly assess why activities qualify as research and development. So do not wait until December to start gathering the information.

Have your 2027 WBSO application prepared?

Klaren Subsidieadvies has been supporting technical companies since 2004 in identifying, structuring and filing WBSO applications — which projects qualify, which bottlenecks are relevant, how your own technical development is delineated, and which hours, costs and expenses can be budgeted. Want to start on 1 January 2027? Then contact us well before 20 December.

Frequently asked questions about the 20 December 2026 WBSO deadline

CHECKED BY PETER KLAREN · WBSO SPECIALIST SINCE 2004
LAST SUBSTANTIVELY UPDATED: 3 OCTOBER 2026

Source: RVO — WBSO calendar and conditions of the scheme (final filing date 20 December for a 1 January start date; helpdesk not available on weekend days).