Jurisdiction — Foreign investor — Nationality — ICSID Convention, Article 25 — Dual nationality — Effective nationality — Whether an effective nationality test must be read into Article 25 of the ICSID Convention — Whether the explicit exclusion from jurisdiction of dual nationals who held the nationality of the host State was the only jurisdictional bar related to a natural person’s nationality under the ICSID Convention

Applicable law — Customary international law — Diplomatic protection — Effective nationality — ICSID Convention, Article 27(1) — Whether the rules of customary international law applicable in the context of diplomatic protection applied to determine nationality in investor–State arbitration

Jurisdiction — Investment — ICSID Convention, Article 25 — Salini test — Legality — Whether the four elements of the Salini test must necessarily be met to determine the existence of an investment — Whether the three objective criteria of contribution, duration and risk were both necessary and sufficient to define an investment within the framework of the ICSID Convention — Whether the applicable BIT imposed further limits on protected investments — Whether the investment fell within the scope of the requirement of legality under municipal law

Jurisdiction — Investment — Shares — Evidence — Burden of proof — Whether the share certificates were valid under the law of the host State — Whether the heavy burden of proof of alleged impropriety was met — Whether the claimant held legal title over the share certificates said to constitute the investment

Evidence — Burden of proof — Impropriety — Whether the burden of proof of any allegations of impropriety was particularly heavy

Costs — Frivolous proceedings — ICSID Convention, Article 61(2) — ICSID Arbitration Rule 28 — Whether an arbitral tribunal had discretion in frivolous proceedings to allocate the arbitration costs and the legal fees and expenses between the parties by ordering the losing party to bear in full the costs of the arbitration and the entirety of the legal fees and expenses incurred by both parties