If your business employs cross-border workers living in neighbouring countries like Belgium or Germany, you're likely familiar with the 25% rule: if an employee performs 25% or more of their work in their country of residence, social security contributions must generally be paid there—unless the Telework Framework Agreement applies. But what if that same employee spends a significant amount of time working outside the EU? Should those non-EU workdays be included in the calculation? This seemingly simple question has far-reaching implications. And it’s currently under review by the European Court of Justice (ECJ).
Why non-EU workdays matter
Whether workdays outside the EU count towards the 25% threshold can dramatically impact which country’s social security system applies. If non-EU work is included, employees gain more flexibility to work from their country of residence without triggering social security contributions there. But if it's excluded, the percentage of EU workdays done at home increases—and may push employees over the 25% mark sooner than expected.
A real-life example
Take the case of a Belgian employee working for a Dutch employer:
If non-EU workdays are included, only 21% of total work is done in Belgium (48 of 230 days), keeping the employee under the 25% threshold and subject to Dutch social security.
If excluded, the employee performs 48% of EU workdays in Belgium (48 of 100 days), making them liable for Belgian social security contributions.
This technicality has real consequences for your business operations, payroll obligations, and employee tax position.
Pending ECJ ruling
As of June 2025, the Advocate General has issued an opinion: work performed outside the EU should be counted when calculating the 25% threshold. A final ruling from the ECJ is expected by the end of 2025. If confirmed, this will give cross-border workers more flexibility and could align with the way many employers already operate.
What about the Telework Framework Agreement?
If an employee works from home and the 25% rule is triggered solely due to teleworking, the Telework Framework Agreement allows up to 49.99% remote work from the country of residence—without changing the applicable social security system.
But there’s a catch:
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Regular A1 certificates for multi-state workers are issued by the country of residence.
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Framework Agreement certificates must be issued by the country of the employer.
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Retroactive application is limited to 3 months.
This makes it essential to plan ahead and be clear about which calculation method is applied.
What to do now?
With uncertainty still looming, a practical and proactive approach is key:
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Identify employees who may be affected: cross-border commuters with frequent non-EU business travel.
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Communicate clearly with your staff about your company’s approach.
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Apply for the correct A1 certificate—and make sure it reflects the chosen calculation method.
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Pending the final ECJ ruling, we advise excluding non-EU workdays in your A1 applications.
Need help managing A1 certificates?
At Bol International, we help employers navigate the complexities of A1 certificates for EU commuters. Our team can help you assess your employees’ situation, apply the correct method, and ensure your business stays compliant—across borders.
