Part 2 Determining the Applicable Attorney–Client Privilege Standard, 9 Applicable Privilege Standard in Investor–State Arbitration and Comparison with International Commercial Arbitration

In investor–state arbitrations, which are concerned with the resolution of disputes between foreign investors and states parties over the state’s exercise of its public authority in relation to legislative, administrative, or judicial measures, the parties often invoke attorney–client privilege as a defence to document production requests. This chapter therefore examines how arbitral tribunals have determined the applicable attorney–client privilege standard in investor–state arbitration. It reports on several procedural orders and decisions issued by arbitral tribunals constituted under the North American Free Trade Agreement and other bilateral or multilateral treaties. As in these proceedings attorney–client privilege claims often arise together with Cabinet privilege claims, the tribunals’ findings on the applicable Cabinet privilege standard are presented as well. Lastly, the chapter explores whether the solution proposed for international commercial arbitration can also be adopted in investor–state arbitration.