An A1 Certificate is the official document issued under Regulation (EC) No 883/2004 that confirms which EU or EEA member state's social-security scheme covers a worker. Its purpose is to prevent a worker from paying social-security contributions in two countries simultaneously when they are posted abroad or carry out activities across borders.
The certificate is issued by the competent institution of the sending member state, typically the national social-security authority. In the Netherlands, SVB (Sociale Verzekeringsbank) issues A1 certificates. The document must be obtained before the posting begins and must be presented to the host-country authorities on request. It remains valid for the agreed posting period, up to a maximum of 24 months for postings under Article 12 of the Regulation.
Employers who fail to obtain an A1 Certificate before a cross-border posting risk double social-security liability and administrative penalties in the host country. Since 2019, enhanced enforcement under the Enforcement Directive (2014/67/EU) has increased spot-checks at worksites across the EU, making timely application essential for any international assignment.