The two problem pillars of multiple proceedings in investment arbitration: why the abuse of process doctrine is a necessary remedy and requires focus in UNCITRAL’s ISDS reform

Abstract With multiple proceedings in investment arbitration, various problems emerge. This article demonstrates they ultimately rest upon two pillars: a threat to the investor–state dispute settlement (‘ISDS’) system (i) and inequality of arms (ii). Since conventional instruments are insufficient to address these, the abuse of process doctrine is not only useful but also necessary to fill the gaps. However, the doctrine is prone to weaknesses. Therefore, guidance on the doctrine is desirable for it to reach its full potential as a successful mechanism to combat exploitative multiple proceedings. UNCITRAL’s current ISDS reform could serve this purpose. This articles’ analysis shows the reform efforts do recognize multiple proceedings as a problem. However, the path Working Group III is taking to address such is not clear but fades. That would be a lost opportunity. UNCITRAL’s ISDS reform should include guidance on unresolved issues of the abuse of process doctrine to help tackling exploitative multiple proceedings in investment arbitration.