New circular letter on Special Tax Regime for Incoming Taxpayers (BBIB / RSICI)

The tax authorities have published a new circular letter on the Special Tax Regime for Incoming Taxpayers (STR / BBIB / RSICI – new expat regime). The circular letter aims to clarify the practical implications of the enhancements introduced end of 2025.

The key takeaways from the circular letter are:

• The Special Tax Regime (STR) does not need to be explicitly mentioned in the employment agreement or assignment letter
• The authorities acknowledge the practice of reducing the gross salary in their example for existing contracts
• Deadline for retroactive applications: 9 April 2026
• Retroactive adjustments of employment agreement must be done within 3 months

There is no update on the social security position yet. The 30 % and EUR 90K annual limit currently remain applicable for employees subject to Belgian social security.

• The STR does not need to be explicitly mentioned in the employment agreement or assignment letter
  The authorities have noted that the legislation does not require the STR to be mentioned in the agreement with the employee, to be able to apply or benefit from the regime.
  
  Nevertheless, we always recommend to clearly document the positions and benefits of the STR in an addendum to the agreement to avoid any discussions to the maximum extent.  

• Existing contracts: The authorities acknowledge the practice of reducing the gross salary in exchange for Costs Proper to the Employer (CPE) in their example
  The authorities have implicitly acknowledged the practice of lowering gross salary in exchange for more CPE. They have done so in relation to the recently enhanced legislation, so we’ll have to await the authorities’ more general position during audits.
  
  They have also stressed the importance of awareness of the fact that adjusting the gross salary has an impact also on salary components linked to that gross salary. For instance: legal and supplementary pension, vacation pay and social security payments. 

• Deadline for retroactive applications of the STR: 9 April 2026 
  The circular letter confirms the final deadline for retroactive applications for taxpayers who previously did not meet the salary threshold of EUR 75K, but who do qualify for the reduced threshold of EUR 70K.
  
  In case any of your employees could potentially still benefit from this retroactive application and had not been identified previously, do let us know.

• Retroactive adjustments of employment agreement must be done within 3 months
  The tax authorities have added a condition to be able to retroactively benefit from the updated regulations. The existing employment agreements need to be updated within 3 months of publication of the circular letter (i.e. by end of June 2026). Also keep in mind that when retroactive corrections are being applied, the salary forms have to be corrected as such.

Don’t hesitate to contact us in case you would have any questions with respect to the above.