Are the protections offered by EU law adequate alternatives to those offered by international investment law?

This article examines whether the protections provided by European Union (EU) law serve as adequate alternatives to those offered by international investment law (IIL) in the context of intra-EU investment protection following the Achmea ruling and the termination of intra-EU bilateral investment treaties (BITs). It argues that while EU law offers broad protections aimed at creating an "ever-closer" Union and an internal market, these protections differ significantly from IIL's narrower focus on protecting and promoting investments, resulting in divergent interpretations of similar legal concepts, differences in personal and material scope, substantive standards, justifications, procedural protections, and remedies. The article highlights that investor–state arbitration (ITA) and EU legal mechanisms should be seen as complementary rather than competing systems, noting that the Court of Justice of the European Union's (CJEU) antagonistic stance toward ITA overlooks this complementarity. Ultimately, it concludes that EU law protections may not always be sufficient substitutes for IIL protections, especially given procedural challenges and differing adjudicatory communities involved in dispute resolution.