In <span class="news-text_italic-underline">Decision 4A_359/2025</span>, handed down on 15 January 2026, the Swiss Supreme Court dismissed an application by Russian energy company Gazprom to set aside an International Chamber of Commerce (“<span class="news-text_medium">ICC</span>”) arbitral award in favour of Ukrainian state-owned gas company Naftogaz. The award had ordered Gazprom to pay USD 1.37 billion to Naftogaz under a contract governing the transit of Russian gas through Ukraine — a contract that contained an ICC arbitration clause.
Naftogaz commenced ICC arbitration proceedings in September 2022. That same month, Gazprom wrote to the ICC disputing the validity of the arbitration agreement and rejecting the jurisdiction of any tribunal the ICC might constitute. Thereafter, Gazprom took no further part in the proceedings. In 2023, the ICC appointed a co-arbitrator on Gazprom's behalf and confirmed the constitution of the tribunal. The tribunal duly affirmed its own jurisdiction and issued an award in favour of Naftogaz.
Gazprom subsequently sought to set aside the award on a number of grounds, most notably alleging that the tribunal had been improperly constituted. Specifically, Gazprom contended that both the presiding arbitrator and the co-arbitrator nominated by Naftogaz lacked impartiality on account of their nationality, they were nationals of states that Russia had designated as "unfriendly" following the imposition of Western sanctions in the wake of the Russia–Ukraine conflict. In respect of the presiding arbitrator, Gazprom further alleged connections to Naftogaz's legal counsel, as well as pointing to certain statements and social media activity relating to the conflict.
The Swiss Supreme Court rejected Gazprom's challenge in its entirety. The Court's analysis centred on Article 182(4) of <span class="news-text_italic-underline">The Swiss Private International Law Act</span> (“<span class="news-text_medium">PILA</span>”), which provides that a party that continues with arbitral proceedings without raising an immediate objection to a procedural breach may not invoke that breach at a later stage. Gazprom argued that this provision was inapplicable in its case, on the basis that it had not "continued with the arbitral proceedings" within the meaning of the statute, having taken no part in the proceedings following its initial letter to the ICC.
The Court dismissed this argument. It emphasised that the underlying purpose of Article 182(4) of the PILA is to prevent a party from holding procedural objections in reserve — as a form of insurance policy — to be deployed only if the award proves unfavourable. Throughout the arbitration, the tribunal had kept Gazprom informed of all procedural developments and Gazprom had been at liberty to raise objections or challenge the arbitrators at any time. Its failure to do so meant that it had forfeited the right to rely on such objections before the Court.
This decision is of considerable significance for practitioners and parties engaged in international arbitration seated in Switzerland. The ruling makes clear that the preclusion mechanism under Article 182(4) of the PILA applies equally to parties who choose not to participate in proceedings as it does to those who actively engage. Non-participating respondents should therefore be acutely aware that their absence from the proceedings does not preserve their procedural rights. On the contrary, by failing to raise objections during the course of the arbitration, such parties risk being barred from challenging the resulting award on grounds of procedural irregularity or improper constitution of the tribunal.
<span class="news-text_medium">Case Reference:</span> <span class="news-text_italic-underline">Decision 4A_359/2025</span> (Swiss Supreme Court, 15 January 2026)
