Facts

Parties and subject matter of the proceedings: The claimant, a company incorporated in Singapore ([A.] Pte Ltd), filed a revision request against the respondent, the Commonwealth of Australia, pursuant to Art. 190a PILA. The subject matter of the proceedings was the arbitral award of an arbitral tribunal seated in Geneva dated 26 September 2025 (PCA No. 2023-40), in which the arbitral tribunal declined jurisdiction to rule on an investment arbitration claim brought by the claimant. The claimant sought the setting aside of the arbitral award and the challenge of the arbitrators Gabrielle Kaufmann-Kohler, William Kirtley and Donald Rae.

Background of the arbitration proceedings: The claimant is economically connected to the Australian mining group [B.] Pty Ltd, which had concluded a State Agreement with the government of the State of Western Australia regarding iron ore mining since 2001. Following a restructuring of the group in 2018, the claimant was established as a holding company and took over the shares of [B.] Pty Ltd. The claimant alleged that the respondent had breached the State Agreement by enacting the «Iron Ore Processing ([B.] Pty Ltd) Agreement Amendment Act 2020» (Amendment Act). Both parties are Contracting States to the «Agreement Establishing the ASEAN-Australia-New Zealand Free Trade Area» (AANZFTA), which contains investment protection provisions in Chapter 11. The claimant initiated arbitration proceedings under the UNCITRAL Rules with the Permanent Court of Arbitration (PCA) on 29 March 2023.

Arbitral tribunal’s decision: In its arbitral award dated 26 September 2025, the arbitral tribunal declared itself incompetent as it did not qualify the claimant as a protected investor within the meaning of Chapter 11 AANZFTA. The claimant filed both an appeal (4A_531/2025) and a revision request (4A_633/2025) against this decision. The Federal Supreme Court examined the revision request first, as its acceptance would have resulted in the setting aside of the arbitral award.

Claimant’s revision request: The claimant alleged that the arbitrators had breached their duties of independence and impartiality by rendering the arbitral award without sufficient consideration of the extensive procedural material (a total of 114,489 pages). It claimed that the arbitrators had spent only a few seconds per page (e.g., Donald Rae: 3.6 seconds, William Kirtley: 5.6 seconds, Gabrielle Kaufmann-Kohler: 14.8 seconds), whereas the respondent had invested 20 minutes per page. It further alleged that the arbitral tribunal had ignored central arguments of the claimant and relied on points not raised. The claimant asserted that it had only discovered these circumstances after receipt of the arbitral award (26 September 2025) and following a due diligence review (24 November 2025).

Considerations

1. Admissibility of the revision request The Federal Supreme Court first examined the admissibility of the revision request. Pursuant to Art. 190a para. 1 lit. c PILA, a revision may be requested if a ground for challenge under Art. 180 para. 1 lit. c PILA was discovered only after the arbitral proceedings had been concluded despite due care and no other legal remedy is available. The revision is subsidiary to the appeal pursuant to Art. 190 PILA. The Federal Supreme Court examined the matter ex officio and found that the challenged arbitral award constitutes a revisable final award within the meaning of Art. 190a PILA.

2. Subsequent discovery of the ground for challenge The claimant alleged that it had only discovered the circumstances indicating bias on the part of the arbitrators after the issuance of the arbitral award. The Federal Supreme Court rejected this allegation. The information required to calculate the time spent by the arbitrators (fee amounts and hourly rates) was already known to the claimant as of the arbitral award dated 26 September 2025. The claimant could therefore have raised the alleged ground for challenge in the appeal (4A_531/2025) within the 30-day time limit. However, the claimant had not raised a challenge pursuant to Art. 190 para. 2 lit. a PILA in its appeal, but only in the revision request.

3. No subsequently…