Achmea v. Slovakia

Slovak Republic v. Achmea BV (Case C-284/16) was decided by the Court of Justice of the European Union (CJEU) on 6 March 2018. The dispute originated when Dutch insurer Achmea (formerly Eureko) won a damages award against Slovakia under the 1991 Netherlands–Czech and Slovak Federative Republic Bilateral Investment Treaty (BIT), after Slovakia reversed a partial privatisation of its health insurance market. Slovakia challenged the award in German courts, which referred questions on EU law compatibility to the CJEU.

The Grand Chamber ruled that Articles 267 and 344 TFEU preclude investor-state dispute settlement (ISDS) clauses in intra-EU BITs. The reasoning rested on three points:

• Arbitral tribunals constituted under intra-EU BITs may interpret or apply EU law.
• Such tribunals are not "courts or tribunals of a Member State" within the meaning of Article 267, so they cannot refer preliminary questions to the CJEU.
• This removes disputes from the EU judicial system and threatens the autonomy of EU law.

The judgment effectively invalidated ISDS provisions in roughly 190 intra-EU BITs then in force. In response, 23 EU Member States signed the Agreement for the Termination of Intra-EU BITs on 5 May 2020, formally terminating most such treaties and disapplying their sunset clauses.

Achmea's reach was later extended in Republic of Moldova v. Komstroy (C-741/19, 2021) and Republiken Polen v. PL Holdings (C-109/20, 2021), with the CJEU clarifying in Komstroy that the Energy Charter Treaty's ISDS mechanism likewise cannot apply intra-EU. The ruling is a touchstone in debates over the relationship between international investment law and EU constitutional law, and is frequently raised by EU Member States seeking to annul or resist enforcement of intra-EU arbitral awards, including before ICSID tribunals and in non-EU enforcement jurisdictions.