Can You Challenge an Arbitrator's Decision in Switzerland?

If you are a party to a Swiss-seated arbitration and suspect that an arbitrator lacks impartiality or independence, can you challenge an arbitrator’s decision, or the arbitrator personally, before the proceedings conclude? The short answer is yes, but Swiss law draws a sharp line between challenging an arbitrator during proceedings and seeking to set aside an award after it is rendered. Article 180 of the Swiss Federal Act on Private International Law (PILA) provides the statutory framework for challenging arbitrators in international cases, while the Swiss Rules of International Arbitration set out the institutional procedure for challenges administered by the Swiss Chambers’ Arbitration Institution (SCAI).

Success depends on identifying a valid ground, acting with strict promptness, and choosing the correct procedural route.

Before diving into the detail, keep this three-point checklist in mind:

• Identify the ground. Does the concern fall within Article 180 PILA, improper appointment, lack of independence, or lack of impartiality?
• Act immediately. A challenge must be raised as soon as the relevant facts become known; delay risks waiver.
• Choose the correct route. Institutional challenge under the Swiss Rules or court-level set-aside application to the Swiss Federal Supreme Court (SFSC), the two paths have different procedures and timelines.

When and What Can Be Challenged, Scope and Distinctions

Challenge an arbitrator vs set-aside an award

Swiss arbitration law recognises two fundamentally different mechanisms, and confusing them is a costly mistake. A challenge to an arbitrator targets the person sitting on the tribunal. It is raised during the arbitration and aims to remove the arbitrator before or while the case is being decided. A set-aside application, by contrast, attacks the award itself after it has been rendered, on grounds enumerated in Article 190(2) PILA, including irregular constitution of the tribunal.

From a practical standpoint, the triggers that justify a challenge during proceedings include doubts about impartiality or independence, failure to meet agreed qualifications, and procedural incapacity. If a party discovers a disqualifying fact only after the award is issued, the set-aside route to the SFSC becomes the sole remedy. Industry observers note that the SFSC treats post-award challenges with particular scrutiny, since a party that knew or should have known about a ground during the proceedings and failed to act will generally be held to have waived it.

This distinction matters for arbitration counsel structuring their response: act during the proceedings wherever possible, or accept a much harder burden later.

Article 180 PILA, Text, Interpretation and SFSC Practice

Text and sub-paragraphs of Article 180

Article 180 of the PILA governs the challenge of arbitrators in international arbitrations seated in Switzerland. Under Article 180(1), an arbitrator may be challenged on three grounds:

• (a) Improper appointment. The arbitrator does not meet the qualifications agreed upon by the parties.
• (b) A ground for challenge exists under the applicable arbitration rules. Where parties have chosen institutional rules, such as the Swiss Rules, the challenge grounds set out in those rules apply.
• (c) Circumstances that give rise to justifiable doubts as to the arbitrator’s independence or impartiality. This is the most commonly invoked ground and the one that generates the most SFSC jurisprudence.

Article 180(2) provides that a party may challenge an arbitrator it has appointed, or in whose appointment it participated, only for reasons that become known after the appointment. Article 180(3) stipulates that, unless the parties have agreed otherwise, the challenge is decided by the arbitral institution or, failing that, by the juge d’appui (the state court at the seat of arbitration).

The “reasonable third person” test, how the SFSC applies it

The SFSC has consistently interpreted Article 180(1)(c) PILA by applying an objective standard: would the circumstances give rise to justifiable doubts as to the arbitrator’s impartiality or independence in the eyes of a reasonable third person? This mirrors the approach found in the UNCITRAL Model Law and the IBA Guidelines on Conflicts of Interest in International Arbitration.

In practice, the SFSC does not require proof of actual bias. It is sufficient that objective circumstances, viewed by a disinterested observer with knowledge of the relevant facts, create an appearance of partiality or dependence. The SFSC has emphasised that the test is deliberately stringent: arbitrators are expected to exhibit the same degree of independence and impartiality as state-court judges.

The practical implications are significant. A party does not need to show that the arbitrator’s decision was influenced by bias; it only needs to demonstrate facts that would cause a reasonable person to doubt the arbitrator’s neutrality. Late-discovered connections, such as an undisclosed financial relationship between the arbitrator and a party, can support an Article 180 PILA challenge even after proceedings have advanced, provided the challenging party acts promptly once the facts come to light.

Bias and Independence in Practice, Disclosure, Examples and Checklists

Disclosure duties: what to disclose and when

Swiss arbitration law imposes an ongoing obligation on arbitrators to disclose any circumstances that may give rise to doubts about their independence or impartiality. Under Article 179(6) PILA, a prospective arbitrator must disclose any such circumstances without delay. The Swiss Rules reinforce this obligation: Article 11 of the Swiss Rules requires a prospective arbitrator to sign a statement of acceptance, availability, impartiality, and independence, and to disclose any facts or circumstances that might call these qualities into question.

The duty is not limited to the moment of appointment. It continues throughout the proceedings. If a new circumstance arises, for example, the arbitrator’s law firm begins acting for one of the parties in an unrelated matter, the arbitrator must disclose it immediately. Failure to disclose is itself a factor that reinforces justifiable doubts in the eyes of the SFSC.

Examples of disqualifying and non-disqualifying conduct

Understanding what crosses the line from acceptable professional connection to disqualifying bias requires examining realistic scenarios. The following examples reflect the general direction of SFSC practice:

• Likely to succeed, financial ties. An arbitrator holds shares in a company that is a subsidiary of one of the parties and fails to disclose this. Financial interests create a direct conflict that satisfies the reasonable third-person test.
• Likely to succeed, concurrent counsel relationship. The arbitrator’s law firm is acting as counsel for one of the parties in a separate, ongoing dispute. Even if the arbitrator personally is not involved, the institutional connection raises justifiable doubts.
• Likely to succeed, repeated appointment by one party. An arbitrator has been appointed by the same party or the same counsel in multiple arbitrations over a short period, suggesting a pattern of dependency.
• Unlikely to succeed, prior academic publication. The arbitrator published an article on a legal issue relevant to the dispute. General scholarly opinions do not, without more, demonstrate prejudgment of the specific facts.
• Unlikely to succeed, social acquaintance. The arbitrator and counsel for one party attended the same conference or professional event. Casual professional contacts are generally insufficient.
• Borderline, previous arbitral appointment. The arbitrator previously sat on a tribunal that decided a related (but not identical) dispute involving one of the parties. The outcome will depend on whether the prior case involved overlapping factual or legal issues that create an appearance of prejudgment.

A practical “do/don’t” checklist for counsel assessing arbitrator bias and independence in Switzerland:

• Do check arbitrator databases and public records for financial, professional, or institutional connections before confirming an appointment.
• Do request a detailed disclosure statement and compare it against your own due diligence.
• Do preserve written evidence of any newly discovered facts.
• Don’t delay raising a concern once you become aware of it, even preliminary internal deliberation can be construed as acceptance.
• Don’t assume that a minor, disclosed connection will automatically support a challenge. The SFSC applies the reasonable third-person test rigorously and dismisses unsubstantiated challenges.

Swiss Rules Challenge Procedure, How to Challenge an Arbitrator Under Institutional Rules

Notice of challenge and who decides

Under the Swiss Rules of International Arbitration, the procedure for challenging an arbitrator is governed by Article 12. A party wishing to challenge an arbitrator must submit a written statement to the SCAI setting out the facts and circumstances on which the challenge is based. The challenge must be filed within the time limit specified in the Swiss Rules, the critical requirement is promptness, with the challenge to be raised as soon as the challenging party becomes aware of the relevant circumstances.

Once a challenge is submitted, the other parties and the challenged arbitrator are invited to comment. If the challenged arbitrator does not voluntarily withdraw and the other parties do not agree to the challenge, the decision is made by the SCAI. The SCAI’s decision on a challenge is final under the Swiss Rules, meaning it cannot be appealed to the institution, although a party may raise irregular constitution of the tribunal as a ground for setting aside the eventual award before the SFSC.

Emergency arbitrator and expedited procedure

The Swiss Rules include provisions for both emergency arbitrator proceedings (Article 43) and an expedited procedure (Article 42). Under the expedited procedure, disputes below a specified amount in dispute are heard by a sole arbitrator, and the award is to be rendered within six months. This accelerated timeline places heightened pressure on parties to identify and raise any challenge to the arbitrator’s independence or impartiality at the earliest opportunity. A delayed challenge in an expedited case can derail the entire timetable, creating significant cost and tactical consequences.

For Switzerland-seated institutional arbitrations, the Swiss Rules procedure is generally faster and more streamlined than a court-based challenge, but it requires discipline in documentation and timing.

Deadlines and Tactical Timeline for Challenging an Arbitrator in Switzerland

The single most important rule governing challenge of arbitrator Switzerland deadlines is the principle of promptness. Swiss law, and the SFSC in its consistent case law, requires that a party raise its challenge as soon as it becomes aware of the grounds. There is no fixed statutory deadline in days, which makes it essential for counsel to act without delay and to document the date on which the relevant facts came to light.

Counsel checklist for timing:

• Record the exact date and means by which the ground for challenge became known.
• Serve the challenge notice in writing within the shortest possible timeframe, the SFSC has treated delays of even a few weeks as evidence of waiver.
• If an interim measure or emergency relief is needed, consider filing simultaneously or in close sequence to avoid gaps in protection.
• Preserve the entire record of communications, disclosures, and supporting evidence.

Court-Level Set-Aside vs Challenge to Arbitrator, The SFSC Route

When to go to state courts

If an arbitrator challenge is unsuccessful during proceedings, or if the disqualifying facts come to light only after the award has been rendered, the affected party’s remedy is to apply to the SFSC to set aside the award. Under Article 190(2) PILA, the grounds for setting aside an international arbitral award include:

• (a) Irregular appointment or constitution of the arbitral tribunal.
• (b) Erroneous decision on jurisdiction.
• (c) Decision on matters beyond (or failure to decide matters within) the scope of the arbitration agreement.
• (d) Violation of the right to be heard or equal treatment.
• (e) Incompatibility with public policy.

For arbitrator challenges, Article 190(2)(a) is the most directly relevant ground. The SFSC reviews whether the tribunal was properly constituted in light of the requirements of Article 180 PILA. A successful set-aside on this ground results in the annulment of the award, typically requiring the dispute to be re-heard by a reconstituted tribunal.

The SFSC is the sole court of review for international arbitral awards seated in Switzerland, there is no intermediate appellate layer. Early indications from recent SFSC practice suggest that the Court typically renders its decision on a set-aside application within four to six months of receipt. The SFSC’s review is limited to the specific grounds enumerated in Article 190(2); it does not conduct a merits review of the underlying dispute. Parties should therefore be realistic about the scope of relief available: setting aside an award does not result in the SFSC substituting its own decision on the merits.

Practical Strategy, Costs and Risks

Not every suspicion of bias warrants a formal challenge. Counsel should weigh the strength of the evidence, the practical consequences, and the risk of waiver against the costs and potential delays. A decision-tree approach can guide the analysis:

• Trivial connection, fully disclosed: Acknowledge the disclosure, note any reservations on the record, but do not challenge. An unsuccessful challenge can damage credibility with the tribunal and the institution.
• Significant, undisclosed conflict: File a challenge immediately. Delay creates a serious risk of waiver and undermines the party’s position if the issue is later raised in set-aside proceedings.
• Borderline case: Conduct thorough due diligence, take legal advice, and, if in doubt, reserve rights in writing and challenge promptly. The cost of a challenge (institutional fees, legal costs, potential delay) is generally modest compared to the risk of enforcing or defending an award tainted by an irregularly constituted tribunal.

Industry observers expect that parties who fail to raise a timely challenge during proceedings will face an uphill battle if they attempt to rely on the same ground in set-aside proceedings before the SFSC. The waiver principle is applied strictly, and the SFSC has little sympathy for tactical delay.

Key Comparison, Swiss Rules vs PILA / Ad Hoc Challenges

Practical tip: In institutional arbitrations under the Swiss Rules, the streamlined SCAI procedure is almost always the first port of call. Reserve the court route for post-award challenges or situations where the institutional mechanism has been exhausted or is unavailable.

Conclusion, Can You Challenge an Arbitrator’s Decision in Switzerland?

Swiss law provides robust mechanisms for parties to challenge an arbitrator’s decision, or, more precisely, to challenge the arbitrator or seek annulment of the resulting award. Article 180 PILA sets out clear grounds, the Swiss Rules offer a streamlined institutional procedure, and the SFSC provides a final layer of judicial review. The critical success factors are promptness, proper evidence, and strategic judgment about when a challenge is warranted. For parties involved in Swiss-seated arbitrations, early engagement with experienced arbitration counsel is essential to protect procedural rights and avoid the risk of waiver that comes with delay.

Sources

1. Federal Act on Private International Law (PILA), Fedlex
2. Swiss Rules of International Arbitration (2021), Swiss Arbitration Association
3. Swiss Federal Supreme Court (Bundesgericht), Case Law Portal
4. Swiss Code of Civil Procedure (ZPO), Fedlex
5. Swiss Chambers’ Arbitration Institution (SCAI)
6. UNCITRAL, Arbitration Rules and Texts