On 1 April 2026, the Belgian tax authorities (BTA) published Circular letter 2026/C/51, providing commentary on the amendments made by the Law of 18 December 2025 to the special tax regime for inpatriate taxpayers (BBIB) and for inpatriate researchers (BBIO). The changes apply to remuneration paid or granted as from 1 January 2025.
Without providing an overly extensive explanation of the special tax regime or of the changes introduced by the Law of 18 December 2025 — we refer to our earlier newsflashes for this — we briefly reiterate the key takeaways below.
Beneficiaries of the special tax regime (BBIB and BBIO) are eligible for a tax-free allowance of 30% of gross remuneration, subject to a maximum of EUR 90.000. One of the conditions (applicable only to BBIB) is that the individuals concerned must receive a minimum salary of EUR 75.000 on an annual basis.
Through the Law of 18 December 2025, changes were made to this system. The tax-free allowance was increased from 30% to 35%, and the cap of EUR 90.000 was abolished. In addition, the minimum salary threshold (applicable only to BBIB) was reduced to EUR 70.000. The changes took effect retroactively as from 1 January 2025.
The circular letter confirms that employers and employees who already benefit from the regime may, subject to compliance with applicable labour law, retroactively amend existing employment contracts to reflect the new fiscal parameters. Such amendments must be made no later than three months after the publication of the circular letter (i.e. until 30 June 2026) and may take effect as from the date of the start of the employment in Belgium, and at the earliest as from 1 January 2025.
Concretely, the following adjustments can be reflected in amended employment contracts:
- The annual gross remuneration threshold is reduced from (more than) EUR 75.000 to (more than) EUR 70.000.
- The percentage of the tax-free allowance is increased from 30% to 35% of gross remuneration, and the former absolute cap of EUR 90.000 per year is abolished.
The circular letter illustrates this with an example. An employee with an annual gross remuneration of EUR 77.000 and an allowance of EUR 23.100 (30% of EUR 77.000) could, following a contract amendment, see his gross remuneration reduced to EUR 74.148,15 and his allowance increased to EUR 25.951,85 (35% of EUR 74.148,15), without any additional payment being made.
When such retroactive amendments are made, one should consider that the individual salary statements (so-called fiches 281.10) must be corrected to reflect the adjusted remuneration, and a corrective wage withholding tax return should be filed.
Side Note: Social Security Aspects
Reference should be made to the fact that the NSSO (National Social Security Office) has not aligned with the amendments to the expatriate regime introduced by the Law of 18 December 2025. The NSSO continues to adhere to the “original” conditions and limits (30% tax-free allowance and a cap of EUR 90.000). This creates a discrepancy between the fiscal and social security treatment of the allowance granted under this system.
It was even only as of March 2026 that the NSSO has agreed to the reduction of the income threshold from EUR 75.000 to EUR 70.000 in order to benefit from the regime (also with effect from 1 January 2025).
Action Points
Employers and companies should review existing inpatriate arrangements to assess whether adjustments to employment agreements might be beneficial for their employees. If applicable, it is recommended to review the 2025 payroll to ensure any adjustment to the employment contract is properly implemented.
If you would like to receive more information on the applicability of the special tax regime to your population, or if you would like assistance with applying for the regime and ensuring its correct processing in payroll, please do not hesitate to contact us.
***
For more insights on this subject, please do not hesitate to reach out to your regular PwC contact, or contact Emmanuel Saporito or Bart Van den Bussche.
