This means that there are special common EU/EEA rules that state that an employee is only socially insured in one country at a time, and which country that is. Similar coordination rules exist with Switzerland through separate agreements. However, a recent ECJ ruling seems to put this principle at risk if EU commuters work simultaneously in the EEA and in Switzerland.
New ECJ Ruling
According to the ECJ, separate agreements govern the EU’s coordination with Switzerland and with the EEA countries. These agreements must be applied independently. As a result, if an employee works across the EU, the EEA and Switzerland, the applicable social security legislation must now be determined separately for each jurisdiction.
This ruling also has implications for work involving the UK. Since the Brexit agreement only covers social security between the EU and the UK, and separate bilateral agreements apply to the UK’s relationship with the EEA and Switzerland, three different A1 certificates may now be required for an employee working across these regions.
Why this matters for employers
This new interpretation may lead to multiple social security obligations for one employee — something that contradicts the core principle of EU social security coordination, which aims to ensure coverage in only one country at a time.
Even more challenging: under this new approach, each country will only consider the work performed under their respective bilateral agreement. This could significantly affect the assessment of whether an employee performs a “substantial part” of their work in their country of residence — a key condition in determining applicable legislation.
Real-world example
Let’s say an employee lives in the Netherlands, is employed by a Swiss company, and works:
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40% in Switzerland
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40% in Liechtenstein
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20% in the UK
Under the previous all-in-one approach
Because the employee does not work at least 25% in the Netherlands, the applicable social security would fall under Swiss rules (employer’s country).
Under the ECJ's new split approach
Each agreement must be applied separately:
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Under the EU–Switzerland agreement → only Swiss work is considered → subject to Swiss social security.
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Under the EU–EEA agreement → only Liechtenstein work is considered → subject to Liechtenstein social security.
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Under the EU–UK agreement → only UK work is considered → subject to UK social security.
Result
Three different social security systems may apply — a compliance nightmare for both employers and employees.
Dutch policy (for now)
Despite the ruling, Dutch authorities still treat Switzerland, Liechtenstein, Norway and Iceland as part of the EU territory under Regulation (EC) No 883/2004. In practice, this means that for now, the Netherlands continues to apply the all-in-one approach. But keep in mind: when the employee resides in another EU country, the local authority in that country will process the A1 application — and they may take a different view.
Need help navigating EU social security compliance?
At Bol International, we support internationally active companies in navigating complex cross-border employment and compliance issues — including social security, A1 certificate applications, and the practical impact of ECJ rulings.
If you employ staff across borders and want to ensure compliance under the latest developments, our team is here to advise you.
