This article focuses on mobility of companies in the European Union in the light of the Court of Justice’s judgment in the C-106/16 Polbud – Wykonawstwo sp. z o.o. case. The Court of Justice has once again interpreted the treaty provisions relating to the EU freedom of establishment in the context of cross-border conversion of companies. The in-depth analysis of the case from the substantive law perspective as well as from the conflict-of-law perspective has raised some doubts with regard to the background of the judgment. Therefore, the article assesses whether the cross-border transfer of a seat took place in the Polbud case or the cross-border conversion, or possibly a new company has come into existence. Most of the analysis is aimed at exposing the risks related to the companies’ mobility under the rules adopted in the Polbud judgment, in particular in the absence of respective European and national regulation.

This article deals with the problem of the right to social security in the state of residence in the light of Regulation No 883/2004 on the coordination of social security systems. The judgment of the Court of Justice of 8 May 2019 in case C-631/17 SF v Inspecteur van de Belastingdienst served as an inspiration for the above-mentioned topic. In its judgement the Court has made a binding interpretation of Article 11(3)(e) of the said Regulation in the context of the situation of a national of a member state employed as a seaman on board a vessel flying the flag of a third state by an employer established in a member state other than the worker’s state of residence. The aim of the article is to justify the right to social security in the state of residence based on Article 11(3)(e) of the Regulation 883/2004. The analysis shows that it is necessary to introduce appropriate changes to the Polish legislation on the social security system. Simultaneously, as far as seafarers are concerned, it is desirable to consider the specificities of the work at sea, including the introduction of maritime social security as a specific type of social security, similar to French law for instance. The changes should be introduced gradually to avoid the risk of decline in the employment of Polish seafarers by EU shipowners.

The article reviews European Union case law on ship registration and sea-faring in EU member states. The EU, aside from encouraging ship registration in member states, enacts choice of law rules in order to mandate the EU lawor domestic law of member states as proper law for seafaring. Today, the larger number of major Polish shipowners fly a flag of convenience (such as Greece or Cyprus), which means Polish merchant ships do not carry Poland’s civil ensigns.