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Part III Guide to Key Jurisdictional Issues, 17 Counterclaims in Investment Treaty Arbitration

The last decade has seen an increase in the efforts of respondent States to have their own claims against investor-claimants heard in investor-State proceedings commenced against them. The investment arbitration case law has revealed a host of legal and practical difficulties in admitting counterclaims. Most of these stem from the core requirement that parties must consent to submit their differences to investment arbitration. The applicable arbitration rules have also been cited as a bar to counterclaims. This chapter explores the functionality of applicable procedural rules as bases for an investment tribunal’s authority to hear counterclaims under the two main investment law regimes: the International Centre for Settlement of Investment Dispute (ICSID) Convention and Arbitration Rules and the United Nations Commission on International Trade Law Arbitration Rules. A review of the milestone cases under these two regimes reveals the major problems that have arisen.