Counterclaims in Investor-State Arbitration: A Tale of Two Cases

This article explores the evolving role of counterclaims in investment treaty arbitration. While arbitral rules commonly permit counterclaims, their success has historically been limited due to challenges such as the scope of the parties’ consent to arbitration and the lack of a relevant investor obligation to ground the counterclaim. However, a discernible increase in counterclaims under the ICSID Convention over the past 15 years suggests that there may be a shift in practice. Against this backdrop, this article carries out a comparative analysis of two recent decisions – Iberdrola v. Guatemala (2020) and Lopez Goyne Family Trust v. Nicaragua (2023) – highlighting key similarities and differences in reasoning and discussing their broader significance.