The 2026 International Chamber of Commerce (ICC) Arbitration Rules introduce a suite of procedural reforms designed to improve efficiency, streamline case management and reduce the time and cost of arbitration.
Whilst expert witnesses or expert evidence are not explicitly referenced in the new provisions, the cumulative effect of these reforms is likely to reshape how and when expert evidence is prepared, presented and scrutinised within the ICC arbitration process.
This article will focus on a summary of the relevant changes and the impact on experts.
Moving Beyond Mandatory Terms of Reference
Under the 2026 rules, Terms of Reference (ToR) are no longer a necessary step in ICC proceedings, although arbitral tribunals retain the discretion to establish them where appropriate as a useful case management tool.
This places greater emphasis on early case management. The Case Management Conference (CMC), which remains mandatory under Article 24 now has a more significant role – it becomes a central procedural milestone for structuring proceedings and ensuring efficiency from the outset.
The implications for expert witnesses
First, there is likely to be less formal upfront definition of issues. The ToR traditionally played a useful role in crystallising the matters in dispute, often guiding the scope of expert evidence. With the shifting emphasis on the CMC, experts may find that their instructions evolve as proceedings develop.
Second, there will be a need for earlier engagement. Counsel will need to decide before the CMC whether expert evidence is required. This may compress the timeframe for expert instruction and initial analysis.
Early determination mechanism (Article 30)
Early determination has formed part of the ICC arbitral practice since October 2017 under the Note to Parties and Arbitral Tribunals on the Conduct of the Arbitration. This mechanism allows tribunals to dispose of claims or defences that are manifestly without merit or outside their jurisdiction at an early stage.
The reforms formalise the position by integrating this mechanism into the ICC Rules.
The implications for expert witnesses
Where issues are suitable for early dismissal, tribunals may decide matters without the need for the full evidence process. For experts, this means that:
- Some engagements may never progress to full reporting stages.
- Expert involvement may become more targeted and strategic.
- Early-stage input (e.g. preliminary views) may become more valuable than full reports.
The introduction of a new Highly Expedited Arbitration Procedure (HEAP)
HEAP is a new procedure designed to deliver decisions on a significantly compressed timetable. The suitability of HEAP does not depend on the value of the claims but instead on the complexity of the issues and the parties’ interest in a swift resolution of their dispute.
HEAP is likely to be most suitable for:
- lower-complexity commercial disputes,
- claims with a simple factual matrix, or
- a distinct aspect of a dispute, which requires swift resolution – such as technology or sports-related disputes or purchase price adjustments.
HEAP is not intended for procedurally complex disputes.
The implications for expert witnesses
The HEAP “fast-tracking” process has the potential to exclude expert evidence. However, the criteria for allocating cases under HEAP seems to suggest that they would not ordinarily require expert evidence.
Whether or not expert evidence is required in HEAP disputes will likely be decided on a case-by-case basis.
If expert evidence is permitted, experts could be subject to tighter time constraints, or the nature of their evidence could be restricted to written expert evidence, condensed reports or a single joint expert.
Greater tribunal control and scrutiny
The reforms reflect a wider institutional emphasis on active case management and efficiency. Tribunals are encouraged to take a more interventionist approach to ensure proceedings remain proportionate and focused.
The implications for expert witnesses
For expert witnesses, this is likely to translate into:
- Increased scrutiny of whether expert evidence is required at all.
- Closer control over the scope of expert reports.
- Greater use of procedural tools such as:
- joint statements of issues
- concurrent expert evidence (hot tubbing)
- limits on report length or number of experts.
Experts may therefore be asked to provide more concise, issue-focused opinions with less tolerance for expansive or marginal analysis.
Conclusion
The 2026 ICC Rules reinforce a clear direction of travel: arbitration should be faster, more streamlined and tightly managed.
Although the Rules do not introduce explicit changes to expert evidence, the practical implications are clear:
- Expect earlier involvement, but potentially shorter engagements.
- Be prepared to work within tighter procedural timetables.
- Focus on clarity, concision and relevance in expert reports.
- Anticipate greater tribunal oversight of methodology and scope.
Experts who adapt to these expectations will be well placed to continue playing a pivotal role in ICC arbitrations under the new regime.
How we can help
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