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A1 Certificate: definitions, relevance and application of Regulation 883/2004 on social security for posted workers

The A1 certificate is a document attesting that workers, when posted to another Member State, remain subject to the social security legislation of their country of origin.

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In the ever-changing context of international employment, the A1 Certificate – often referred to as A1 Document or the INPS Posting Certificate – often plays a key role in securing the rights and benefits of posted workers in the European Union (EU). This document is a manifestation of the European Social Security Agreement, specifically regulated by Regulation 883/2004.

The A1 Certificate: definitions

The A1 certificate is a document attesting that workers, when posted to another Member State on behalf of the employer (or on their own account, in the case of self-employed workers), remain subject to the social security legislation of their country of origin. This document certifies that workers remain subject to the social security laws of their home country, despite working temporarily abroad, and aims at preventing the imposition of double contributions by ensuring that expatriates receive the social security benefits to which they are entitled.

One of the main objectives of the A1 Certificate is to avoid double payment of social security contributions. In the absence of this document, a worker posted abroad could be subject to the social security laws of both the home and host country, resulting in overpayments and administrative burdens.

Regulation 883/2004: the source of the A1 Certificate

To fully analyse the rationale behind the A1 certificate, it is crucial to understand the legal framework on which it is based. Regulation 883/2004, a cornerstone of European social security coordination, sets out the rules for determining the social security legislation applicable when a worker moves within the EU.

Regulation 883/2004 aims to ensure that persons working in different EU Member States can continue to enjoy the same social security rights and benefits as in their home Member States.

The A1 certificate is issued by the competent social security authority in all cases where the conditions for posting the worker provided for by Community law (Article 12 and Article 13, Regulation 883/2004 and Article 14, Regulation 987/2009) are met.

Article 12 of Regulation 883/2004

In particular, Article 12 of Reg. 883/2004 establishes that an employee or self-employed worker who is posted to an EU country, in the presence of all the conditions required by Community law, remains insured, for social security purposes, in the country of origin. For the entire period of the posting (maximum 24 months or if the request for an extension for a longer period is granted) social security contributions must be paid in the country of origin.

Article 13 of Regulation 883/2004

Article 13 of Regulation 883/2004, on the other hand, addresses the exercise of an employed and/or self-employed activity in two or more Member States. In this regard, it is stipulated that a worker may pursue an activity as an employed and/or self-employed person in two or more EU Member States.

In such cases, a single social security legislation must apply to the worker and social security contributions must be paid in a single EU state, as if all activities were carried out in that state. For this to be possible, the worker must inform the social security institution of the country in which he resides, so that it can be determined, according to the criteria laid down in Community legislation, which social security legislation is to be applied.

A1 Certificate – INPS in Italy

Italy, like the other EU Member States, plays an active role in the implementation of the A1 Certificate. If an Italian worker is temporarily assigned to work in another EU country, the release of the A1 certificate guarantees compliance and proof of affiliation with the Italian social security system. In this way, continuity of social security coverage is guaranteed.

The submission of the A1 Certificate application in Italy must be presented by the employer or social security intermediary electronically, and transmitted to the INPS office with territorial competence.

The employer or self-employed worker must request the certificate through the special platform provided by the Istituto Nazionale della Previdenza Sociale – INPS. When transmitting the request, details of the assignment, including the expected duration of the posting, and the work address in the host country must be provided.

The importance of the A1 Certificate for posted workers

In addition to being a key element of compliance with posting regulations, the Model A1 is of great importance for both workers and posting companies. It ensures that workers receive the social security benefits to which they are entitled, even while working in a different EU Member State and at the same time simplifies internal administrative procedures for posting companies, reducing the complexities associated with cross-border employment.

The document must always be kept and made available to the competent authority in the event of an inspection, both during and after the posting abroad.

For more information on the EU regulatory framework for the posting of workers, take a look at our guide on EU Posted Workers Directives.

The A1 Certificate Post-Brexit

Following Brexit, the A1 certificate has undergone significant developments for the United Kingdom (UK) and the European Union (EU). The UK is no longer an EU Member State, but has negotiated separate agreements with the EU and individual Member States to maintain social security coordination.

Pending the EU’s ratification of the Trade and Cooperation Agreement (TCA) with the UK, the two parties have arranged for the provisional application of the Agreement. The TCA regulates the coordination of social security after Brexit through a special protocol – the Protocol on Social Security Coordination (PSSC) – which is valid for 15 years from the entry into force of the Agreement.

UK-based companies must continue to apply for the A1 certificate when posting workers to EU countries, thereby ensuring that their employees remain covered by the UK social security system on assignment abroad.

Similarly, EU companies posting workers to the UK are obliged to apply for Form A1 with the relevant national authorities.

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Regulatory Framework

Regulation (EC) No 883/2004 of the European Parliament and of the Council of 29 April 2004


Learn more about Posting of Workers to Europe

Have a look at our in-depth guides about Posting of Workers to EU Countries. If you don’t know where to start, you can have a first look at our introduction on Posting of Workers to Europe.

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