Generative artificial intelligence (GenAI) has disrupted traditional copyright frameworks by enabling large-scale ingestion of protected works for model training, sparking litigation and regulatory responses in the United States and the European Union. While existing debates focus on domestic law doctrines such as fair use and text-and-data-mining exceptions, this paper explores an underexamined dimension: the potential role of international investment law (IIL) in disputes arising from state measures—or omissions—affecting copyright holders. Many international investment agreements (IIAs) explicitly include intellectual property within the definition of ‘investment,’ raising the possibility that failures to enforce copyright or permissive regulatory stances toward AI training could trigger claims under standards such as full protection and security (FPS), fair and equitable treatment (FET) or indirect expropriation. Drawing on arbitral jurisprudence and doctrinal analysis, the paper evaluates the jurisdictional threshold for copyright-based investments and examines the viability of ISDS claims in this context. It concludes by finding that there are possible scenarios where certain claims could be successful.