This article looks into the meaning of the concepts of sincere cooperation, mutual trust, and mutual recognition in EU social security coordination. It analyses the legislative choice of coordination as the main regulatory mechanism in the field, and examines the role of administrative
cooperation. Furthermore, the article highlights the challenges that arise in situations where mutual recognition is required under the Regulations, as in connection with portable documents relating to the posting of workers. It also considers the limits to mutual trust via the principle of
prohibition of fraud and abuse of rights established in the case law of the CJEU on free movement. In the last few years, this principle has been extended into the field of social security law, notably in Altun. In this way, the coordination regime does not require totally blind trust: rather,
it balances the Member States' interests of maintaining the integrity of their social security systems with the Union interest of simplifying free movement. As in other fields of EU law relating to free movement, the mutual trust between the Member States in social security coordination may
therefore be set aside in extraordinary cases.
Recent developments in the approximation of EU private international laws: towards mutual trust, mutual recognition and enhancing social justice in civil and commercial matters
