By Katarina Mirkovic
On 7 January 2026, the Secretary-General of the International Centre for Settlement of Investment Disputes (ICSID) registered a request for arbitration filed by Hiroshi Osumi (Japan) against the Swiss Confederation (ICSID Case No. ARB/26/1). Under ICSID practice, registration is an institutional act by the Secretariat confirming the formal receivability of the request. It does not prejudge jurisdiction, nor any assessment of breach, causation, or quantum. Conceptually, it marks the shift from a pre-dispute posture to a structured adversarial process in which jurisdiction and admissibility typically crystallise before the merits.[1]
Background of the dispute: why “debt instruments” and “finance” point to Credit Suisse AT1
The newly registered case has been associated with the Credit Suisse rescue and, in particular, with FINMA’s March 2023 decision to write down CHF 16.5 billion of Additional Tier 1 (AT1) instruments to zero in the context of the UBS takeover.[2] If the dispute indeed turns on that write-down, the central issue is not merely one of economic loss, but of legal characterisation: how an emergency resolution measure adopted in the interest of financial stability interfaces with treaty-based standards of investor protection.
Moreover, in October 2025, Switzerland’s Federal Administrative Court held that FINMA’s AT1 writeoff lacked a sufficient legal basis and seriously interfered with bondholders’ property rights, while leaving open what remedy would ultimately follow and noting the possibility of appeal.[3] While such a domestic legality finding is not dispositive in treaty arbitration, it may nonetheless inform the tribunal’s assessment of due process, transparency, reasonableness, and the surrounding regulatory context.
The legal hook: the Switzerland-Japan Economic Partnership Agreement and its ISDS clause
The claim is framed as a breach of the investment protections contained in the Agreement on Free Trade and Economic Partnership between Japan and the Swiss Confederation, in force since 1 September 2009.[4] From the perspective of consent, the treaty operates as the State’s standing offer to arbitrate, which a qualifying investor accepts by initiating proceedings; the arbitration agreement is thus formed by the interaction between treaty consent and the investor’s submission of the dispute.
Crucially, that Agreement contains an investor-state dispute settlement mechanism. Article 94 provides that if a dispute cannot be settled through consultations within six months, an investor may submit the dispute to ICSID arbitration, among other options, and it contains the familiar “consent” language by each Party to arbitration.[5] This matters because the consultation period and any accompanying admissibility conditions are not mere formalities: they structure the dispute temporally and may become jurisdictional or admissibility battlegrounds if contested.
The UNCTAD Investment Policy Hub also classifies the agreement as a treaty with investment provisions and links to the full text.[6]
So the jurisdictional architecture is not mysterious: the treaty itself furnishes a pathway to ICSID for qualifying investors.
What the “registration” tells us, and what it does not
Registration means the request has cleared a threshold set by the ICSID Secretariat and the case is now formally pending. It does not mean that:
- the tribunal exists already (it still needs to be constituted),
- jurisdiction is established (Switzerland may raise objections),
- or that any compensation is due.
Put differently, the claimant has secured access to the procedural forum, but not yet to the adjudicatory competence of the tribunal. Jurisdiction remains to be established through the applicable treaty, the notion of “investment”, and the claimant’s standing as an investor.
But it does mean that Switzerland is now in the procedural posture of a respondent State in a live ICSID arbitration, with all the predictable consequences: counsel team, internal record gathering, and early strategy on jurisdiction, admissibility and merits framing.
Why the case is significant for Switzerland, even before we see the pleadings
There are at least four reasons this registration matters, even on sparse public information.
- Switzerland is being tested as a respondent State in a finance-crisis decision
Investment arbitration is often associated with infrastructure, energy assets, or classic expropriation scenarios. Here, the dispute appears anchored in a bank-resolution emergency and its treatment of capital instruments. That is a particularly sensitive category of dispute because it sits at the intersection of public stability measures and private investor loss allocation. In investment law, this is precisely where the most conceptually difficult cases arise: the tribunal must balance deference to legitimate regulatory objectives against the minimum content of investor protection, without converting the treaty into a general insurance scheme against macroeconomic shocks. - The treaty lever is not a BIT from the 1990s, but a modern FTA-style investment chapter
The Japan-Switzerland agreement is a broad economic partnership treaty with an investment chapter and an ISDS clause that expressly mentions ICSID.[7] This matters because these clauses often embed specific procedural filters (consultations, time limits, waiver logic) that can shape jurisdiction fights early. Accordingly, the dispute is likely to be shaped not only by substantive standards, but by the architecture of the treaty itself: definitions, scope clauses, fork-in-the-road or waiver mechanics (if applicable), and the sequencing of pre-arbitration steps.
- Domestic litigation and international arbitration are moving in parallel
The Swiss administrative-court finding of unlawfulness on the FINMA writeoff, and the broader global litigation around AT1 instruments, create a messy multi-forum environment. Treaty tribunals sometimes treat domestic decisions as factual context rather than dispositive law, but they are rarely irrelevant. Parallel proceedings do not predetermine the outcome, but they can shape argumentation on attribution, the reasonableness of regulatory conduct, and the investor’s legitimate expectations, as well as the tribunal’s approach to factual complexity. - “Debt instruments” claims are not theoretical anymore
Law-firm and practitioner commentary has been openly discussing treaty routes for Credit Suisse AT1 holders for some time, signalling that the pipeline of claims is not limited to a single filing.[8] More broadly, the case illustrates the progressive ‘financialisation’ of investment arbitration: disputes increasingly concern regulatory choices affecting financial instruments, rather than the classic paradigm of physical asset takings.
What happens next
Procedurally, the next visible milestones tend to be:
- constitution of the arbitral tribunal,
- any early jurisdictional objections by Switzerland,
- and potentially publication of redacted procedural decisions, depending on transparency choices.
At the moment, the most concrete takeaway is this: the claim has moved from a contingent risk into a formally pending ICSID proceeding. It is now on the ICSID docket.
The legally prudent reading remains modest: registration confirms procedural viability, not substantive responsibility. Still, once registered, a case typically requires immediate action on document preservation, internal fact mapping, and early jurisdictional strategy.
Update (October 2026)
Since this note was first written, the proceeding has moved well beyond registration. The arbitral tribunal was constituted on 21 May 2026: it is presided over by Marinn Carlson, appointed by the parties, and composed of Peter Turner KC, appointed by the claimant, and Gabriel Bottini, appointed by Switzerland, with Geraldine R. Fischer acting as Secretary of the Tribunal, and the first session was held on 29 June 2026.[9] On 10 July 2026 the Tribunal issued Procedural Order No. 1, which confirms that the proceeding is governed by the ICSID Arbitration Rules in force as of 1 July 2022 and which, at this early stage, denied the claimant’s request, formulated in its Request for Arbitration of 12 December 2025, for an order requiring Switzerland to produce 592 documents referenced in, but not made public with, the report of the Parliamentary Commission of Inquiry established by the Federal Assembly, dated 17 December 2024; the denial is, however, without prejudice to the claimant renewing the request in the document production phase, once both parties have set out their full factual and legal positions.[10] On the same day the Tribunal issued Procedural Order No. 2 on transparency and confidentiality, under which the parties consent to the publication of the award by ICSID with agreed redactions, whereas hearings are not open to the public, the parties’ written submissions are published only if a party seeks the publication of its own main pleadings, and supporting documents (exhibits, legal authorities, witness statements and expert reports) are not published at all.[11]
The procedural record also lends support to the connection with the Credit Suisse rescue suggested above, although the published orders do not mention the AT1 instruments by name: ICSID records the subject of the dispute as “debt instruments” in the finance sector, the claim rests on the 2009 Agreement on Free Trade and Economic Partnership between Japan and the Swiss Confederation, under whose Article 94(10) the procedural timetable expressly envisages a possible submission by Japan as the non-disputing Party, and the parliamentary report on which the claimant relies is the one in which the Commission of Inquiry examined the conduct of the authorities in the context of the emergency takeover of Credit Suisse.[12] On the domestic front, FINMA announced on 15 October 2025 that it would appeal the Federal Administrative Court’s partial decision to the Federal Supreme Court.[13] Finally, on 3 August 2026 Switzerland filed a request for security for costs and a request concerning advances on costs, on which the parties exchanged further observations until 7 September 2026.[14]
[1] ICSID registration reported via Italaw, “Registration of the Request for Arbitration”, 7 January 2026. https://italaw.com/cases/14438
[2] Reuters, 4 December 2025, describing Japanese investors initiating an ICSID complaint over the AT1 wipeout.
[3] Swiss court rules $20 billion Credit Suisse bond write-off unlawful, by Dave Graham, John Revill and Oliver Hirt, Reuters, 14 October 2025
[4] Japanese investors sue Switzerland over Credit Suisse’s AT1 write-down, law firm says, by Reuters, 4 December 2025.
[5] Japan-Switzerland FTEPA text, Article 94 on settlement of investment disputes, hosted by SECO and Japan’s MOFA.
[6] UNCTAD IIA entry for Japan-Switzerland EPA (2009)
[7] SECO and MOFA treaty text; Article 94.
[8] Financial services blog: The Write down of Credit Suisse AT1 Bonds Keep the Courts Busy, by Kurt Blickenstorfer, Bratschi blog https://www.bratschi.ch/en/publikationen/financial-services-blog-the-write-down-of-credit-suisse-at1-bonds-keep-the-courts-busy
[9] ICSID, Case Details, Hiroshi Osumi v. Swiss Confederation (ICSID Case No. ARB/26/1), https://icsid.worldbank.org/cases/case-database/case-detail?CaseNo=ARB/26/1, accessed 5 October 2026; Procedural Order No. 1, 10 July 2026, §2.1.
[10] Hiroshi Osumi v. Swiss Confederation, ICSID Case No. ARB/26/1, Procedural Order No. 1, 10 July 2026, §§1.1 and 15.9–15.14, https://icsidfiles.worldbank.org/icsid/ICSIDBLOBS/OnlineAwards/C13188/DS21811_En.pdf, also available on Italaw, https://italaw.com/cases/14438.
[11] Hiroshi Osumi v. Swiss Confederation, ICSID Case No. ARB/26/1, Procedural Order No. 2 on Transparency and Confidentiality, 10 July 2026, §§12–17, https://icsidfiles.worldbank.org/icsid/ICSIDBLOBS/OnlineAwards/C13188/DS21872_En.pdf.
[12] ICSID, Case Details, see note 9; Procedural Order No. 1, see note 10, §15.9 and footnote 4, and Annex B; Swiss Parliament, “Lessons from the Credit Suisse crisis”, press release, 20 December 2024, https://www.parlament.ch/press-releases/Pages/mm-puk-2024-20-12.aspx?lang=1033.
[13] FINMA, “FINMA to appeal partial decision of the Federal Administrative Court concerning AT1”, 15 October 2025, https://www.finma.ch/en/news/2025/10/20251015-meldung-bvger-at1/.
[14] ICSID, Case Details, see note 9, procedural details of 3, 24 and 31 August and 7 September 2026.
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