Res Iudicata and Interlocutory Decisions under the ICSID Convention: Antinomies over the Power of Tribunals to Review

There is little doubt that res iudicata is a general principle of law. But its application in investment treaty arbitration remains varied. A recent fracture in the case law of investment tribunals concerns the apparent dilemma of the res iudicata effect, if any, of interlocutory, i.e. pre-award, decisions rendered under the ICSID Convention. The article explores res iudicata and its scope in light of the formal distinction between decisions and awards under the ICSID Convention. It engages critically with the relevant case law and argues that, in contrast to awards, decisions do not carry the res iudicata effect. But the absence of res iudicata does not mean that the reopening of a decision is always justified and special regard must be had to the specific circumstances.