On 23 February 2026, a Programme Bill was submitted to Parliament introducing, among other measures, a substantial reform of all existing regimes that provide exemptions from the obligation to remit wage withholding tax (précompte professionnel / bedrijfsvoorheffing).

The draft legislation proposes a broad moderation of these exemption regimes for the period 2027–2029, impacting all current mechanisms.

Below is a concise overview of the existing framework and the amendments proposed under the Programme Bill.

Existing wage tax exemption regimes

Articles 275/1 to 275/12 of the Belgian Income Tax Code 1992 (CIR 92) provide for several targeted exemptions from the obligation to remit wage withholding tax to the Treasury. The main regimes include amongst other:

• Article 275/1 CIR 92 – Exemption for overtime work
• Article 275/3 CIR 92 – Exemption for researchers (R&D)
• Article 275/5 CIR 92 – Exemption for shift work and night work
• Article 275/6 CIR 92 – Exemption for sporting activities (professional athletes and young athletes)
• Article 275/8 and 275/9 CIR 92 – Exemption for investment and job creation in support zones
• Article 275/10 CIR 92 – Exemption for qualifying start-ups
• Etc

These regimes allow employers, subject to strict conditions, to retain part of the wage withholding tax that would otherwise be payable to the Treasury.

Objective of the proposed amendment

The draft legislation introduces a general moderation mechanism across all wage withholding tax exemption regimes, implemented through a mandatory correction factor.

According to the government, the measure seeks to contain the overall budgetary cost of these tax expenditures for the Treasury.

In practice, the mechanism aims to freeze total expenditure at 2026 levels for the period 2027–2029, thereby neutralising:

• the impact of inflation,
• the automatic indexation of wages, and
• the resulting increase in wage withholding tax on those indexed salaries.

Mechanism: application of a correction factor

Under the proposal, employers will be required, when filing the wage withholding tax return, to apply a correction factor to the amount of withholding tax not remitted under the exemption regime. The resulting adjusted amount represents the maximum portion that may be retained.

The correction factors proposed are:

• 97% for remunerations paid or attributed between 1 January 2027 and 31 December 2027
• 93.35% for remunerations paid or attributed between 1 January 2028 and 31 December 2028
• 95.9% for remunerations paid or attributed between 1 January 2029 and 31 December 2029

The Programme Bill also specifies how the correction factor must be applied for each exemption regime individually.

Practical illustration (Article 275/3 CIR 92 – R&D exemption)

Assume that in 2026, an employer benefits from a monthly exemption of EUR 97,000 under Article 275/3 CIR 92 for qualifying researchers.

Further assume that in 2027:

• salary costs remain stable in real terms,
• inflation develops as anticipated,
• wages are indexed accordingly, and
• wage withholding tax increases as a result.

Without a corrective mechanism, the exemption for January 2027 would increase to EUR 100,000.

Applying the 97% correction factor: EUR 100,000 × 97% = EUR 97,000

The employer may therefore retain EUR 97,000, and EUR 3,000 must be remitted to the Treasury.

In the wage withholding tax return, the employer must declare:

• the original exemption amount before applying the correction factor (EUR 100,000), and
• the reduction resulting from the correction factor (EUR 3,000) under a dedicated code.

Notably, the correction factor also applies when salary costs decrease, for example due to a lower number of eligible employees. The factor is applied to the exemption amount for the relevant month regardless of changes in headcount.

Regimes with limited duration

Certain exemption regimes currently apply only until 31 December 2026, including:

• the “shift work‑bis” regime (Article 275, §1/1 CIR 92), and
• the “continuous work‑bis” regime (Article 275, §3/1 CIR 92).

As these regimes expire at the end of 2026, the Programme Bill does not provide for the application of the correction factor to them.

However, the parliamentary documents clarify that if future legislative initiatives extend these regimes, the application of a correction factor will need to be reconsidered accordingly.

AKD continues to closely monitor the legislative process and will provide further updates as soon as the final texts are adopted or additional guidance becomes available.

Should you wish to discuss the wage withholding tax exemption regimes in more detail or assess the potential impact of the proposed measures on your organisation, please contact your usual AKD contact person or Frédéricq Jacquet.