Part IV Guide to Key Substantive Issues, 19 The Law Applicable in Investment Treaty Arbitration

Abstract

Investment treaty arbitration, being an arbitral process, in no way differs from international commercial arbitration in that the principle of party autonomy is the primary rule governing the arbitration, including as regards the law applicable to the substance of the dispute. When the applicable law has been chosen by the parties, the arbitrators have a duty to apply such law and nothing but such law. It is only in the absence of a choice by the parties that the arbitrators are entitled to exercise a degree of discretion in the determination of the applicable law. This chapter examines each of these situations in turn, before considering whether the specific nature of investment protection treaties has implications in terms of choice of law process.