The principles of independence and impartiality are foundational in ensuring the fairness and legitimacy of international arbitration. However, with the increasing complexity of arbitration proceedings and the growing role of social media and technology, these principles are facing new challenges. On February 26, 2025, a new virtual webinar in the series, ITA Reporters Roundtable, highlighted significant issues around arbitrator independence and impartiality, particularly in the face of evolving practices like social media usage and increased transparency in international arbitration. The panel discussion was moderated by Dr. Crina Baltag, FCIArb, a professor of International Arbitration at Stockholm University, member of the Board of the SCC Arbitration Institute, and chair of the ITA Academic Council with over 20 years of extensive practice in various aspects on international dispute resolution, as well as private and public international law, and Monique Sasson, founder of DeliSasson and arbitrator at Arbitra International with particular expertise in international investment law, and featured expert panelists such as Diora Ziyaeva, a partner with Dentons US; Nataliya Barysheva, an associate at MCL Arbitration; and Yoshie Concha Takeshita, also an associate at MCL Arbitration.

It is a fundamental principle of international arbitration that every arbitrator, whether acting as a member of an arbitral tribunal or as a sole arbitrator, must be impartial and independent from the parties not only at the time of accepting the appointment but throughout the entire course of the arbitral proceedings.1See Establishment and Organisation of an Arbitral Tribunal, in REDFERN AND HUNTER ON INTERNATIONAL ARBITRATION, 226 (Nigel Blackby et al. eds., 7th ed. 2023) (hereinafter “REDFERN AND HUNTER”). X1 In many jurisdictions, there is an existing legal obligation to act with independence and impartiality, and to declare any facts or circumstances likely to cast doubts on their impartiality or independence.2See REDFERN AND HUNTER supra note 1 at 227.X2 As these obligations pertain to ethical standards, it is the responsibility of the arbitrator to ensure that the exercise of their adjudicative function remains free from any appearance of bias.3See Stefanie Schacherer, Independence and Impartiality of Arbitrators: A Rule of Law Analysis, 1, 9 (Jan. 2018) (Seminar Paper, Singapore Management University).X3 The disclosure requirements imposed on arbitrators serve as an essential safeguard to protect the parties’ right to an independent and impartial decision-making process. By proactively disclosing any potentially sensitive information, arbitrators can effectively mitigate the risk of bias, thereby preserving the integrity of the arbitration process.

This article reflects on the roundtable’s insights, analyzing the evolving legal standards of arbitrator independence and impartiality, particularly in light of recent French and investment arbitration jurisprudence.

A. The duty to disclose under French law: An ongoing obligation

One of the central themes of the roundtable discussion was the ongoing duty of disclosure that arbitrators must abide by in order to maintain impartiality. This obligation is integral to ensuring transparency in the arbitration process. The standard to be met in deciding what needs to be disclosed varies amongst institutional rules and national arbitration laws.1See REDFERN AND HUNTER, supra note 1, at 227.X1 For example, Article 11.2 of the 2021 ICC Rules makes it clear that the test is both subjective and objective.2ICC Rules (2021), Art. 11.2. See also REDFERN AND HUNTER supra note 1, at 228.X2

In contrast, during the panel discussion, Ms. Barysheva presented the French law approach in a recent set aside proceeding regarding an ICC award, Opportunity Fund and others v. Telecom Italia, where in particular, the Paris Court of Appeal applied an objective standard when assessing an arbitrator's independence, finding that any facts that may give rise to reasonable doubts about an arbitrator’s impartiality must be disclosed.3See Cour d’appel [CA] [regional court of appeal] Paris, May 2, 2024, 21/08610 (Fr.). X3 In this particular instance, the Paris Court of Appeal set aside an ICC award rendered on 1 September 2016 in Paris on the basis of article 1520(2) of the French Code of Civil Procedure (“FCCP”), due to the existence of facts likely to cause, in the minds of the parties, a reasonable doubt as to the presiding arbitrator’s independence.4See id.X4 At first glance, the Court’s decision to set aside the arbitration award may seem severe, as it was based on the ties between the presiding arbitrator’s law firm and a third party interested in the arbitration’s outcome, rather than on any direct involvement of the arbitrator herself.5See Rémi Sassine, Paris Court of Appeal Sets Aside ICC Arbitral Award in a USD 15 Billion Dispute Due to the Irregular Constitution of the Arbitral Tribunal, KLUWER ARBITRATION BLOG (Oct. 28, 2024), https://arbitrationblog.kluwerarbitration.com/2024/10/28/paris-court-of-appeal-sets-aside-icc-arbitral-award-in-a-usd-15-billion-dispute-due-to-the-irregular-constitution-of-the-arbitral-tribunal/. X5

The Court ultimately found that the relationship between the law firm and the third party “constitute[d] an objective situation of conflict of interest likely to raise a reasonable doubt in the minds of the parties regarding the arbitrator’s independence”.6See Cour d’appel [CA] [regional court of appeal] Paris, May 2, 2024, 21/08610, at ¶ 54 (Fr.) (English translation).X6 This view aligns with the ICC’s guidance on conflicts of interest which emphasizes the importance of scrutinizing even indirect relationships for potential conflicts.7International Chamber of Commerce, Note to Parties and Arbitral Tribunals on the Conduct of Arbitration under the ICC Rules of Arbitration, para. 27 (Jan. 1, 2021). X7

In its decision, the Court first examined the relationship between Vivendi, the third party, and Telecom Italia, the party to the arbitration, and concluded that Vivendi had been a significant shareholder of Telecom Italia throughout the arbitration process, with a direct role in its governance. This made Vivendi highly invested in the outcome of the arbitration. The Court then turned to the connection between Vivendi and the arbitrator’s law firm. It noted that the presiding arbitrator’s law firm had a long-standing professional relationship with Vivendi, having provided legal services to the company in the past and intended to continue doing so in the future, despite the ongoing arbitration. The Court found that these strong economic ties between the law firm and Vivendi had been well-established during the arbitration, thus raising concerns about the potential for a conflict of interest. The Court concluded that, while the arbitrator may have been free from bias, the ties between the law firm and Vivendi, the third party, could have compromised the appearance of independence, thus tainting the integrity of the arbitration.

What it is worth noting is that the award was set aside based on the information disclosed by the presiding arbitrator, which may explain why the Court did not address the issue of the arbitrator’s failure to disclose the relevant information. This emphasizes the importance for arbitrators to disclose such relevant information at the beginning of the arbitration, or at the earliest opportunity if the arbitration has already commenced. Taking this proactive approach will help mitigate the risk of an award being annulled under article 1520(2) of the FCCP, even if it means the arbitrator may need to step down from the proceedings.8See Cour d’appel [CA] [regional court of appeal] Paris, May 2, 2024, 21/08610 (Fr.).X8

Moreover, this proactive approach should be observed not only at the beginning of the arbitral proceedings but throughout them. During the panel discussion, Ms. Barysheva indicated that the French courts have consistently reinforced this principle, underscoring that arbitrators have an ongoing obligation to disclose any potential conflicts of interest, particularly business relationships or other affiliations that could raise legitimate concerns regarding their impartiality. This continuous duty is fundamental to preserving the integrity of the arbitration process and ensuring that all parties can trust in the neutrality of the tribunal. So much so that the ICC Rules expressly include this obligation in Article 11.3.9ICC Rules (2021), Art. 11.3.X9 

B. Duty of disclosure of personal relationships

In the Duala case,10See Port Autonome de Douala v. Douala International Terminal S.A., French Court of, Cour de cassation [Cass.] [supreme court for judicial matters] 1e civ., June 19 2024, No. 345 FS-B (Fr.) (“Duala case”).X10 discussed by Yoshie Concha Takeshita, the French Court of Cassation upheld the annulment of an arbitral award rendered by a three-arbitrator tribunal based on doubts as to the impartiality of the presiding arbitrator, Thomas Clay, due to a personal relationship between him and the late Professor Emmanuel Gaillard, counsel representing one of the parties. After the passing of Professor Gaillard, Thomas Clay delivered a public eulogy for his honor. The wording of his tribute, which suggested close personal ties with counsel for one of the parties, was deemed to constitute an objective circumstance capable of raising, in the mind of the opposing party, a reasonable doubt as to the arbitrator’s independence and impartiality, particularly as it indicated, among other things, that he consulted Gaillard “before every important decision.”11See Duala case, at ¶ 17.X11

The Court considered that such an admission “revealed the intensity of a relationship that went beyond mere ordinary friendship”12See id.X12 and held that close professional or personal relationships between an arbitrator and a party’s counsel are special circumstances that arbitrators must take into account when making his or her statement of independence and impartiality throughout the arbitration, and that, apart from these circumstances which are objective factors that must be disclosed, arbitrators must disclose circumstances which, although not included in this list, may give rise to reasonable doubt in the parties’ minds as to the arbitrator’s independence and impartiality (i.e., doubts that may arise for a person in the same situation who has access to the same reasonably available information).13See Duala case, at ¶ 13. After referring to Articles 1520 and 1456(2) of the French Civil Procedure Code, to Article 11 of the ICC Rules (2017 version) to which the arbitration in question was subject, and to the ICC’s guidelines for assessing arbitrators’ disclosure obligations, the Court held that it follows from these documents that “close professional or personal relationships” between an arbitrator and a party’s counsel are special circumstances that arbitrators must take into account when making their statement of independence and throughout the arbitration, and that, apart from these circumstances which are objective factors that must be disclosed, arbitrators must disclose circumstances which, although not included in this list, may be such as to give rise to reasonable doubt in the parties’ minds as to the arbitrator’s independence and impartiality, that is, doubts that may arise in a person in the same situation who has access to the same reasonably available information.X13 

In this context, it is worth mentioning that the ICC’s guidance on the conduct of the arbitration under its rules–which governed the Duala arbitration–addresses the criteria for disclosing potential conflicts of interest, which include personal and professional relationships that could impact an arbitrator’s impartiality or independence.14International Chamber of Commerce, Note to Parties and Arbitral Tribunals on the Conduct of Arbitration under the ICC Rules of Arbitration, para. 27 (Jan. 1, 2021). X14 However, these guidelines do not require disclosure of purely academic or scientific relationships, such as those formed in the context of doctoral-level academic interactions or thesis committees, unless such relationships rise to a level that could reasonably be perceived to affect an arbitrator’s objectivity. Although academic ties were not required to be disclosed by the principles of arbitration, Thomas Clay’s public eulogy for Professor Gaillard raised serious concerns. The eulogy contained statements such as “I admired and loved him,” which the Court found to be a tribute to a respected figure, not an indication of undue influence. However, other more personal passages in the eulogy described the presiding arbitrator’s close relationship with the counsel, including consulting him before making important decisions and referring to him as a friend. These personal references suggested a relationship beyond professional academic ties and appeared to link the personal friendship to the ongoing arbitration.

The French Court of Cassation clarified that the professional ties between lawyers and law professors, particularly within the context of international arbitration and academic circles, such as those formed at the doctoral level or within thesis examination committees, do not, by their nature, imply the existence of “close” professional or personal relationships as defined by the ICC guidelines, as these relationships can be described as academic or scientific at best.15See Duala case, at ¶ 14.X15 

Ms. Concha Takeshita further emphasized the French court’s reliance on an objective test when evaluating the nature of personal or professional relationships that may give rise to concerns about an arbitrator’s impartiality or independence. As an example, a publication by the president of an arbitral tribunal, which refers to close personal ties with a party’s counsel, is an objective fact which may give rise to reasonable doubt in the mind of the other party as to the arbitrator’s independence and impartiality.16See Duala case, at ¶ 20.X16 

This decision reiterates the importance of arbitrators disclosing even personal relationships that may seem innocuous but could give rise to doubts about independence or impartiality due to the intensity and duration of between the relevant individuals.

In investment arbitration, which often involves states and multinational corporations as parties, the public perception of impartiality is especially sensitive.

There are different approaches adopted in investment treaty arbitrations when it comes to the requirements for disqualification of arbitrators. Diora Ziyaeva emphasized that the applicable standard for removal of an arbitrator under the ICSID Convention is the one of manifest lack of impartiality under Articles 14 and 57 of the ICSID Convention. Ms. Ziyaeva highlighted the nuance of Article 14(1), which refers to the ability to “exercise independent judgment” in the English version, but the Spanish version refers to a person who “inspires full confidence in their impartiality of judgment”.1Convention on the Settlement of Investment Disputes between States and Nationals of Other States art. 14(1), Mar. 18, 1965, 17 U.S.T. 1270, 575 U.N.T.S. 159 (English and Spanish versions). See also REDFERN AND HUNTER, supra note 1, at 239. X1 Because both versions of the ICSID Convention are considered equally authentic, Article 14(1) has been applied to require arbitrators to be both impartial and independent.2REDFERN AND HUNTER, supra note 1, at 239. X2 As defined by the Chair of the ICSID Administrative Council in a decision on disqualification of an arbitrator in an ICSID proceeding, “[i]mpartiality refers to the absence of bias or predisposition towards a party. Independence is characterized by the absence of external control”.3Raiffeisen Bank International AG and Raiffeisenbank Austria d.d. v. Republic of Croatia, ICSID Case No. ARB/17/34, Decision on the Proposal to Disqualify Stanimir Alexandrov, May 17, 2018, ¶ 82.X3 

Another important point to consider is that there is no uniform approach regarding the applicable standard for interpreting the requirement in Article 57, which mandates that an arbitrator must demonstrate a “manifest” lack of the qualities outlined in Article 14.4See REDFERN AND HUNTER, supra note 1, at 240.X4 The interpretation of “manifest” has been inconsistent among tribunals. Professor Scheurer in his commentary of the ICSID Convention points out that at least one tribunal has focused on the perception of bias, emphasizing that it relates “not to the seriousness of the allegation but to the ease with which [the allegation] may be perceived.”5See EDF International S.A. and others v. Argentine Republic, ICSID Case No. ARB/03/23, Challenge Decision Regarding Professor Gabrielle Kaufmann-Kohler, Jun. 25, 2008, ¶ 68 (citing CHRISTOPH H. SCHREUER, THE ISCID CONVENTION: A COMMENTARY 932 (1st ed. 2001)).X5 Something is “manifest” if it can be “discerned with little effort and without deeper analysis.”6See id.X6 In contrast, other tribunals have adopted a more stringent view, arguing that “manifest” should pertain to the substance of the conflict itself from the perspective of an informed reasonable person, established facts “make it obvious and highly probable, not just possible, that the challenged arbitrator is a person who may not be relied upon to exercise independent and impartial judgment”.7REDFERN AND HUNTER, supra note 1, at 240 citing Suez, Sociedad General de Aguas de Barcelona S.A. and others v. Argentine Republic, ICSID Case Nos. ARB/03/17 and ARB/03/19, Decision on Second Proposal for Disqualification of a Member of the Arbitral Tribunal, May 12, 2008, ¶ 29; Canepa Green Energy Opportunities I, S.á.r.l.. and Canepa Green Energy Opportunities II, S.á.r.l. v. Kingdom of Spain, ICSID Case No. ARB/19/4, Decision on the Second Proposal to Disqualify Mr. Peter Rees QC, 10 February 2020, ¶ 52.X7 

Notwithstanding the above, the complexities surrounding the duty to disclose in investment arbitration is not exclusive of ICSID. In Rinat Akhmetov v. Russia,8See Cour d’appel [CA] [regional court of appeal] Paris, May 21, 2024, 23/06872 (Fr.), (“Rinat Akhmetov v. Russia”).X8 an investment arbitration under the UNCITRAL Arbitration Rules and administered by the Permanent Court of Arbitration, Andrea Bjorklund, a prominent academic, was recently disqualified from hearing a high-profile investment treaty claim.9See Susannah Moody, US arbitrator disqualified from Russia case over LinkedIn post, GLOBAL ARBITRATION REVIEW (Aug. 21, 2024), https://globalarbitrationreview.com/article/us-arbitrator-disqualified-russia-case-over-linkedin-post. X9 The case concerned a claim brought by Ukrainian citizen Rinat Akhmetov against Russia for the alleged expropriation of his assets in Russian-occupied areas of eastern Ukraine. In this instance, on July 31, 2024, Marietta Agyeiwaa Brew, the appointing authority for the UNCITRAL arbitration, upheld Russia’s challenge to Bjorklund's appointment as an arbitrator. The challenge was based on Bjorklund’s LinkedIn post, which promoted a fundraising initiative for Ukrainian lawyers who had joined the military in the wake of Russia’s 2022 invasion of Ukraine.10See id. X10 In her post, Bjorklund referred to these lawyers as “Ukrainian defenders” and urged support for them, describing their lives as being in danger and highlighting their lack of proper equipment to resist Russian attacks. She called for contributions to support these “defenders” in their fight against Russia.11See id. X11 

In reaching the decision to disqualify Professor Bjorklund, Ms. Brew concluded that the LinkedIn post created an appearance of bias, thus suggesting that an observer might reasonably question whether Professor Bjorklund could conduct the case with the necessary impartiality or independence. However, Ms. Brew did not find evidence of actual bias in Bjorklund’s actions. This case underscores the fact that the duty to disclose in investment arbitration cases goes beyond the actual presence of a conflict of interest, requiring arbitrators to consider how their actions might be perceived by the parties and the public, thereby safeguarding the integrity of the arbitration process. Additionally, Ms. Brew dismissed the other grounds for challenging Bjorklund, including her co-authorship of an amicus curiae brief in support of the former majority shareholders of Yukos in U.S. enforcement proceedings against Russia and McGill University’s public stance on the invasion of Ukraine.12See id. X12

Ms. Ziyaeva noted that the takeaway from Bjorklund’s disqualification should be the importance of maintaining impartiality and independence in arbitration, particularly in high-profile cases with political and international implications. Her LinkedIn post, despite her claims of neutrality, was deemed to create an appearance of bias that warranted disqualification under the relevant arbitration rules. This case highlights the broader challenges of ensuring the appearance of impartiality in arbitrations involving sensitive geopolitical issues and the delicate nature of disclosure requirements for arbitrators.

While the concept of independence and impartiality point to similar concerns, they do not mean the same.1See Stefanie Schacherer, supra note 3, at. 6.X1 Impartiality refers specifically to the absence of bias or predisposition toward any party or legal issue in a given case. It requires arbitrators to exercise their function without any favoritism or prejudice, and to adopt a behavior that minimizes the situations, which could lead to challenges of their function.2See Jirí MÄ›lenovský, L’indépendance des juges internationaux, in 349 RECUEIL DES COURS 9, 29 (Académie de Droit International, 2010).X2 As such, impartiality is not a discretionary attribute but a fundamental duty inherent to the adjudicative role. Independence, by contrast, is broader and it can be said that independence is the precondition for impartial decision-making.3See id. at 26-29.X3 

The roundtable discussion highlighted the ongoing challenges in maintaining independence and impartiality in international arbitration. Recent cases, such as Opportunity Fund and others v. Telecom Italia, the Duala case and Rinat Akhmetov v. Russia, demonstrate the increasing scrutiny placed on arbitrators’ relationships and their social media activities. The evolving standards of proactive disclosure and the duty of curiosity are pivotal in addressing these challenges and ensuring that the arbitration process remains fair and legitimate.

Last, but not least, there is a duty of curiosity which requires arbitrators to actively seek out and disclose any facts or circumstances that could give rise to doubts about their impartiality. As noted by Professor Baltag, this proactive duty is essential to ensure that arbitration remains fair and transparent. The duty of disclosure is the guarantee of impartiality and independence and whether this is followed by the duty to investigate may be another discussion, but both play the same important role—the arbitrator should uphold the duty of disclosure to preserve the procedural integrity of the arbitration proceeding.