Abstract
Although they are generally not subject to appeal the way court decisions typically are, investor-State arbitration awards can be reviewed—and potentially set aside—in a number of ways and on various bases. In this respect, investor-State arbitration under the auspices of ICSID is notable in that it provides a self-contained system for the review of arbitral awards by ICSID-appointed ad hoc committees. In the period 2000–2010, this feature of the ICSID system attracted criticism as ad hoc committees appeared to be overreaching in their review of arbitral awards, exercising less deference to the tribunal’s decisions than what would be expected given the narrow bases for setting aside an award under the ICSID Convention. This article revisits the issue 10 years later, exploring whether ICSID practice has evolved in these areas and whether there remains a greater risk of unexpected de novo review by ICSID ad hoc committees. Looking at recent ICSID annulment decisions as well as the case law of arbitration-friendly jurisdictions, the article concludes that although the ICSID ad hoc committees have recently shown more restraint, they continue to interfere more with the tribunal’s reasoning and decisions than many courts exercising the same function.