1. No requirement to explicitly mention the application of the regimes in the employment agreement
The tax authorities confirm that the application of the regimes does not need to be explicitly mentioned in the employment agreement or assignment letter. The legislation does not impose such a requirement.
2. Existing employment relationships
- Taxpayers who already met the conditions for BBIB/RSII or the BBIO/RSICI before the new law was published and who submitted their application on time do not need to file a new application. The updated rules will automatically apply to them.
- Retroactive amendments to existing employment agreements. Existing employment contracts may be amended to reflect the changes to the regimes with retroactive effect, subject to compliance with employment law.
- These amendments must be implemented within three months following the publication of the Circular Letter, i.e. by 30 June 2026. It’s not entirely clear how the authorities will handle changes enacted from 1 July 2026 onwards.
- For tax purposes, the amendments may then apply retroactively, for example by reducing the annual gross remuneration and/or increasing recurring expense reimbursements.
- Any such changes can take effect from the start of employment in Belgium, but no earlier than 1 January 2025.
- The tax authorities also emphasize that adjusting the agreed gross remuneration may have broader consequences, including an impact on supplementary pension accrual, benefits calculated based on gross salary, such as pensions, holiday pay, and social security benefits.
3. Inbound taxpayers starting work between 1 January 2025 and 9 January 2026
This specifically concerns inbound taxpayers who started working in Belgium between 1 January 2025 and 9 January 2026 but did not meet the former minimum salary threshold of more than €75,000.
- Deadline to apply: 9 April 2026
- If approved, the special tax regime will apply retroactively from the start of the employment in Belgium, but no earlier than 1 January 2025.
- It is irrelevant whether an application for the regime was submitted before 9 January 2026. What does matter is that, at the time employment in Belgium started, it can be demonstrated that the new minimum salary threshold of more than €70,000, and all other conditions were already met.
