On 1 April 2026 Belgium’s Federal Public Service Finance published Circular Letter 2026/C/51, finally explaining how December’s reform of the popular ‘special tax regime for inbound taxpayers and researchers’ will work in practice. Deloitte released an alert on 3 April outlining the key take-aways, and global-mobility managers are already recalibrating cost projections.
![Belgian Tax Authorities Clarify Expat Tax Regime—Higher Employer Cost Allowance Now Retroactive]()
Companies bringing talent into Belgium may also need to ensure immigration documentation keeps pace with tax updates. VisaHQ’s Belgium desk (https://www.visahq.com/belgium/) can streamline work-permit and visa filings for inbound employees, coordinating paperwork with the new salary thresholds so HR teams avoid delays while maximising the revised tax benefits.
The circular confirms that the ceiling on ‘costs proper to the employer’ (CPE)—the tax-free compensation often used to cover housing and schooling—rises from 30 % to 35 % of gross salary and that the previous annual cap of €90,000 is abolished. Crucially, both changes apply retroactively to income earned from 1 January 2025. Employees with salaries between €70,000 and €75,000 who started work in Belgium between 1 January 2025 and 9 January 2026 may file a late application until 9 April 2026. For multinationals the guidance removes months of uncertainty. Payroll teams must amend 2025 withholding returns and Form 281.10 certificates if they opt to apply the higher exemption retroactively. Social-security authorities, however, have not accepted the additional 5 % CPE, meaning that portion remains subject to Belgian social-security contributions—an important budgeting point for assignment cost sheets. The circular also clarifies how salary reductions made solely to hit the new lower €70,000 threshold will affect pension accruals and bonus plans. Employers must document any contract changes within three months of publication to benefit from retroactivity. Failure to act could see assignees lose out on savings of several thousand euros per year. With neighbouring countries such as the Netherlands tightening their 30 % ruling, Belgium’s more generous regime may improve the country’s attractiveness for R&D hubs and EU headquarters, provided companies act swiftly to align contracts and payroll reporting.
Companies bringing talent into Belgium may also need to ensure immigration documentation keeps pace with tax updates. VisaHQ’s Belgium desk (https://www.visahq.com/belgium/) can streamline work-permit and visa filings for inbound employees, coordinating paperwork with the new salary thresholds so HR teams avoid delays while maximising the revised tax benefits.
The circular confirms that the ceiling on ‘costs proper to the employer’ (CPE)—the tax-free compensation often used to cover housing and schooling—rises from 30 % to 35 % of gross salary and that the previous annual cap of €90,000 is abolished. Crucially, both changes apply retroactively to income earned from 1 January 2025. Employees with salaries between €70,000 and €75,000 who started work in Belgium between 1 January 2025 and 9 January 2026 may file a late application until 9 April 2026. For multinationals the guidance removes months of uncertainty. Payroll teams must amend 2025 withholding returns and Form 281.10 certificates if they opt to apply the higher exemption retroactively. Social-security authorities, however, have not accepted the additional 5 % CPE, meaning that portion remains subject to Belgian social-security contributions—an important budgeting point for assignment cost sheets. The circular also clarifies how salary reductions made solely to hit the new lower €70,000 threshold will affect pension accruals and bonus plans. Employers must document any contract changes within three months of publication to benefit from retroactivity. Failure to act could see assignees lose out on savings of several thousand euros per year. With neighbouring countries such as the Netherlands tightening their 30 % ruling, Belgium’s more generous regime may improve the country’s attractiveness for R&D hubs and EU headquarters, provided companies act swiftly to align contracts and payroll reporting.
