Cross border employment and social security within Europe

Sofie Bouwen

Social security costs differ across Europe so it is vital to understand the basics of the cross border rules that apply so your organisation can stay compliant and avoid unnecessary costs, dual contributions and complexity.

Organisations often request employees to work across borders. In some scenarios the cross-border working arises due to the particulars of the employee rather than at the request of the business. For example, the employee may have relocated himself to a new country but continued in the same role. In these scenarios employer and employee taxes and related payroll need to be reviewed. Social security is a key consideration. 

In this article we will discuss the social security position in the EU area and the use of the so-called A1 Form. Common rules for what is known as social security coordination apply to EU member states, Iceland, Liechtenstein, Norway and Switzerland. Amongst the main purposes of the rules is the concept that social security contributions should be payable only in one country (at any given time). As a result, dual social security liabilities should be avoided.

What is an A1 Form?

The A1 form certifies which country social security rules or legislation (exclusively) apply to the holder of the form. This effectively confirms the country in which social security contributions are due.  The form will generally be needed in situations where a person has a connection with more than one EU-country, Iceland, Liechtenstein, Norway and Switzerland. 

The A1 Form is based on the rules contained within European Directive (883/2004) that provides the cross border social security coordination rules. This Directive not only deals with rules for employees, but amongst others also for self-employed persons, civil servants, benefit recipients, pilots/cabin crew etc. We will focus on the rules for employees.

Coordination rules that determine which country social security rules and legislation (and therefore social security contributions) apply: 

The main rule (and starting point) for employees is that the social security legislation of the country where the work is performed is applicable. In special cases or when an employee works in more than one country, there are exceptions to this rule. Below the most common ones are highlighted.

  • When the employee is sent by the employer to work temporarily in another country on his behalf for a maximum period (initially) of 24 months, the employee will remain subject to the legislation of the country were posted from.
  •  When the employee is performing duties in more than one country at the same time, or in alteration, then the employee will be subject to the legislation of the country of his residence provided that the employee works at least 25% of his time in his country of residence. If it is less than 25%, then the employee will be subject to the legislation of the country where the employer is located.
  • As an exception, two or more of the involved countries may by common agreement determine that the employee will be subject to the legislation of the country other than that provided by the normal rules. The A1 form will confirm to which legislation the employee is subject.

Where and when to obtain an A1 form

If the employee goes to work temporarily in another country, the employer will normally apply for the A1 from the relevant authority/institution in the home country (country where sent from). Employees who normally pursue activities in more than one country, apply for the A1 in the country of residence. When an exception to the normal coordination rules is appropriate, the A1 application is made to the authority/institution in the country where the employee would like to be subject to the legislation. Whenever possible, the application should be made before the duties begin in the other country. The legislation determined as being applicable on the Form A1 is normally binding on all countries. The Form should be retained and made available for presentation to the institutions in the countries the employee is working in.

Payroll consequences

The Form A1 confirms the country in which social security is payable. The same form also acts as confirmation that social security is therefore not due in the country the employee is working in.  This form is therefore a very important document to retain for payroll audits.  In some scenarios the social security legislation applies in a country that is different to the country where the employee is employed and on payroll. In these scenarios, the employer will need to be registered and payroll deductions, payments and reporting will apply. It may well be that taxes (wage / payroll taxes) will also have to be paid (and potentially withheld via the payroll). This would mean that a split or shadow payroll may also have to be implemented. 


It’s important to understand the basic rules that apply in Europe. This understanding will help ensure payroll compliance and prevent costly dual social security contributions. 

Sofie Bouwen
Sofie Bouwen
Partner Global Employer Services
Crowe Spark