Belgium Inbound Tax Regime Arizona Measures & Social Security Clarification
Recent tax measures adopted under the Arizona Government Agreement, which may impact employers of international talent in Belgium.
The second batch of tax measures was adopted by Parliament in mid-December 2025 and is laid down in the law of 11 December 2025, which entered into force on 18 December 2025.
This law introduces important amendments to the Special Tax Regime for Inbound Taxpayers and Inbound Researchers.
The first batch of Arizona tax measures, approved and published earlier in 2025, did not include changes to the inbound tax regime. The amendments outlined below were therefore introduced exclusively in this second batch.
The tax measures are intended to apply retroactively to remuneration paid or attributed as from 1 January 2025.
Certain practical aspects remain linked to the publication in the Belgian Official Gazette.
Key inbound tax regime changes - Tax perspective
The law provides for the following income tax changes:
- Increase of the employer allowance from 30% to 35% of qualifying remuneration
- Abolition of the EUR 90,000 cap for income tax purposes
- Lower minimum salary threshold for inbound taxpayers: EUR 70,000 (previously EUR 75,000)
A transitional measure applies to employees who started in 2025 with an annual salary between EUR 70,000 and EUR 75,000, allowing applications within a specific timeframe linked to the publication date.
Important clarification - Social Security Treatment
At this stage, the Belgian social security authorities (ONSS/RSZ) do not align with the income tax changes:
- The additional 5% increase (from 30% to 35%) is not accepted for social security purposes
- The abolition of the EUR 90,000 cap does not apply for social security
- As a result, any allowance above 30% and any amount exceeding EUR 90,000 remains subject to Belgian social security contribution
This distinction is critical when assessing total employment cost, payroll processing and employee communication.
Mini employer checklist
In light of both tax and social security considerations, employers should:
- Identify inbound employees who started in or after 2025
- Verify salary levels against the new EUR 70,000 threshold
- Run dual simulations (income tax vs. social security impact)
- Assess payroll and withholding tax implications, including retroactive effects
- Review employment, assignment and compensation documentation
- Prepare clear employee communication, explicitly addressing the tax vs. social security split
Why this matters
While the law has entered into force, misalignment between tax and social security rules increases the risk of incorrect payroll treatment or employee misunderstanding. Early preparation allows employers to remain compliant and manage expectations.
Would you like support with
- assessing employee eligibility under the new rules?
- preparing tax and social security simulations?
- reviewing inbound tax regime applications or compensation structures?
‘These newly approved measures may create both immediate compliance considerations and longer-term optimisation opportunities for employers with inbound staff.’
Xpatriate supports employers in translating legislative changes into clear, workable solutions — from impact assessment to practical implementation.
If you would like to proactively assess the implications for your inbound population or prepare ahead of formal publication, we would be happy to discuss next steps with you.
