This decision is the latest of several by arbitral bodies of the International Centre for Settlement of Investment Disputes (ICSID) addressing a claim by Amco Asia Corporation (Amco Asia) against respondent Republic of Indonesia. An ICSID tribunal (First Tribunal) in 1984 rendered an award on the merits in favor of claimant Amco Asia. In 1986 an “ad hoc committee” (Ad Hoc Committee) convened on Indonesia’s request pursuant to Article 52 of the ICSID Convention annulled the 1984 award on the grounds that, with respect to a principal holding, the tribunal had “manifestly exceeded its powers” and “failed to state reasons,” both being grounds for annulment specified in Article 52(1) of the Convention. The Ad Hoc Committee did not disturb certain other holdings of the tribunal. Claimant then resubmitted the dispute, and a second tribunal (Second Tribunal) was constituted pursuant to Article 52(6) of the Convention. The first task of the new tribunal was to determine which holdings of the previous bodies were res judicata and therefore could not be relitigated. The three-member ICSID Second Tribunal held: (1) that holdings of the First Tribunal that had not been annulled by the Ad Hoc Committee were res judicata; (2) that issues as to which the First Tribunal’s holdings had been annulled could be relitigated; and (3) that the Ad Hoc Committee’s reasoning, as distinct from its actual decision of annulment, was not binding on the Second Tribunal.