The right of the citizens to free movement is one of the EU fundamental principles . In the area of social security, this entails the duty of the Member States to treat migrating EU citizens as their own nationals not to restrict their ability to work in individual Member States. The national social security schemes of the individual Member States are not harmonised, but merely coordinated. The reason lies in the diversity of the social schemes of these countries, which are based on different principles and have different institutional arrangements. Coordination leaves national legislation unchanged, thus also keeping differences among national schemes. Coordination replaces only those national regulations that are disadvantageous for migrating citizens. For these cases, the EU lays down its own rules of coordination. With regard to the mobility and free movement of employees, self-employed persons and all EU citizens, the special provisions of Regulation (EC) No 883/2004 on the coordination of social security schemes apply. Social security coordination within the EU does not exclude the option to enter into bilateral agreements.
Social security coordination is based on four basic principles that mean the following for migrating workers:
- Under the principle of equal treatment, migrating citizens have the same rights and obligations as the nationals of the Member State in which they stay.
- The principle of single applicable law should help avoid a situation where a migrating citizen is subject to the legislation of multiple countries or is not insured at all. As a general rule, an employee or a self-employed person is subject to the legislation of the country in which he/she works.
- The principle of aggregation of periods of insurance is used in cases where a person spends part of his/herworking life in one Member State and another part in another Member State without reaching the prescribed period of insurance in either of them. The coordination regulations include provisions that allow taking into account the periods of insurance accumulated in other Member States in assessing the entitlement to benefits.
- Under the principle of the exportability of benefits, a beneficiary living outside the Member State where he/she is entitled to a benefit can collect the benefit in the Member State in which he/she resides or stays.