‘Non-assessed’ withholding tax disputes: a legislative remedy

The Belgian legislator passed a law amending Article 368 ITC92 and Article 386/1 ITC92 which allows taxpayers to reclaim non-assessed withholding taxes. The law aims to resolve the uncertainty that recently emerged following two judgements of the Court of Cassation and the Constitutional Court.

Background: uncertainty due to judgements of the Court of Cassation and the Constitutional Court

Article 368 ITC92 foresees a five-year period to reclaim non-assessed (professional) withholding tax (‘bedrijfsvoorheffing en roerende voorheffing’ / ‘précomptes professionnel et mobilier’) from the Belgian State. A similar regime is included in Article 368/1 ITC92 concerning professional withholding tax exemptions (e.g. R&D, shift work exemptions, etc.), for which the law foresees in a three-year period.

Following the Court of Cassation’s judgement of 21 December 2023 and the Constitutional Court’s judgement of 13 March 2025, uncertainty arose on whether the law requires the taxpayer to first file an administrative appeal with the tax administration, or whether the dispute can – or even must – be brought directly before the competent court within the five or three-year period (see our newsflash of 12 September 2025).

In an attempt to address this uncertainty, the Belgian tax administration issued a circular letter (2025/C/56) declaring that a preliminary administrative appeal was indeed required. This position, however, conflicted with the judgements of the Court of Cassation and the Constitutional Court, which meant that taxpayers faced severe uncertainty and possible risks of claims becoming inadmissible (see our newsflash of 12 September 2025).

Legislator clarifies existing uncertainty and solves pending issues

On 18 December 2025, the Belgian legislator passed a law amending Article 368 ITC92 and Article 386/1 ITC92, aiming to resolve the legal uncertainty.

As a result of the adoption of the new law, Article 368 ITC92 and Article 386/1 ITC92 will explicitly require that the claim for withholding tax reimbursement must be carried out by way of a tax appeal (‘bezwaarschrift’ / ‘réclamation’). In other words, the law will treat reimbursement claims as formal administrative appeals. Therefore, taxpayers claiming reimbursement of the withholding tax must first file a tax appeal with the tax administration within the given period, instead of directly bringing the case before the competent court.

This also implies that, if the taxpayer files the tax appeal within the applicable time limits set out in Article 368 ITC92 and Article 386/1 ITC92, the claim cannot become time-barred while awaiting a decision from the tax administration. Even if the standard five-year or three-year limitation periods have expired, the taxpayer may still bring the case before the competent court, provided the administrative appeal was timely filed. The taxpayer must then observe either the six-month waiting period after submitting the appeal (if no decision has been made) or the three-month deadline following the tax administration’s decision, as stipulated in Article 1385undecies of the Belgian Judicial Code.

Furthermore, the legislator also adopted a transitional provision to ensure that all cases brought before the courts within the original time limits of Articles 368 and 368/1 ITC92 are deemed admissible, even if the taxpayer did not pursue the preliminary administrative appeal. This is done to protect the rights of taxpayers who acted in accordance with the Court of Cassation’s judgement of 21 December 2023.

Finally, since the new law will enter into force upon its publication in the Belgian Official Journal, the amendments to Article 368 ITC92 and Article 368/1 ITC92 will have an immediate effect on the administrative claims (tax appeals) still pending a decision. Consequently, these cases may still be brought before the courts even after the five or three-year limitation periods (provided this is done within the limits of Article 1385undecies of the Belgian Judicial Code). This solves the most pressing issue, whereby taxpayers who filed an administrative claim but had not yet received a decision risked having their claims become time-barred following the judgements of the Court of Cassation and the Constitutional Court.