World Investment Treaty Arbitration Update By Wojciech Sadowski and Patrycja Treder (Warsaw) In each edition of Arbitration World, members of K&L Gates’ Investment Treaty practice provide updates concerning recent, significant investment treaty arbitration news items. This edition features the decision on jurisdiction and admissibility in Alemmani and Others v. Argentine Republic, and the decision in Levy and Gremcitel v. Peru. ALEMANNI The decision on jurisdiction and admissibility, rendered on 17 November 2014 in Giovanni Alemanni and Others v. Argentine Republic, ICSID Case No. ARB/07/8, is the third ruling on the admis- sibility of collective actions of investors against sovereign states under international investment treaties. Like the two cases before, i.e., Abaclat and Others v. Argentine Republic, ICSID Case No. ARB/07/5 and of Ambiente Ufficio S.p.A. and others v. Argentine Republic, ICSID Case No. ARB/08/9, the dispute in Alemanni arose from a claim of multiple Italian bondholders related to Argentina’s default on its sovereign bonds. The Alemanni decision is important, as it offers an approach that is distinct from the approach taken by the Abaclat and Ambiente Ufficio tribunals. In particular, it brings into the spotlight the problem of homogeneity of claims brought by individual claimants, as this may have an impact on whether there is one single dispute between the host state and all the claimants. The Alemanni tribunal held that it is possible for there to be multiple claimants. However, its final decision has been delayed until the merits phase, in order to deter- mine whether the claimants have brought only one dispute, which may be characterised by substantive unity. 21