Draft Arbitration Rules of PMAC – Part 4: Evidence and Document Production

On 4 June 2025, the Patent Mediation and Arbitration Centre of the Unified Patent Court (Centre) launched a public consultation to gather feedback on its draft arbitration rules (Draft Rules). In our previous blog posts, we focused on the scope of application, FRAND/SEP disputes and the applicable law and seat of arbitration. This blog examines the provisions on evidence, which are broadly standard provisions, and document production, where the drafters are proposing a slightly novel approach. 

Evidence 

Art 25 of the Draft Rules contains a number of not particularly controversial provisions that are either stipulated expressly in the arbitration rules of other institutions or applied by virtue of the applicable laws.

Art 25(1) of the Draft Rules states that each party bears the burden of proof for the facts it relies on for its claim or defence in accordance with the applicable law. As the authors of the Draft Rules thus correctly recognise, the matter of the burden of proof turns on the applicable law which arbitral tribunals are, in any event, bound to apply. Numerous other rules take the position that there is no need for any express provision dealing with the burden of proof (for instance, Art 25 arbitration rules of the International Chamber of Commerce (ICC Arbitration Rules), Art 28 arbitration rules of the German Arbitration Institution (DIS Arbitration Rules), or Art 50 arbitration rules of the World Intellectual Property Organization (WIPO Arbitration Rules)). Other rules have simply stated the tribunal “shall determine” the burden of proof without providing any further guidance (Art 26(1) Swiss Rules of International Arbitration (Swiss Rules)) whilst the UNCITRAL Arbitration Rules simply stipulate that each party bears the burden of proof for the facts it relies on. 

Since the Draft Rules do not prescribe how the applicable law should be determined, Art 25(1) as drafted will likely have limited practical relevance. Like under other arbitration rules, the parties and the tribunal will need to consider carefully the relevant burden of proof rules as defined by the applicable substantive or procedural law. Parties should therefore agree on the application of an appropriate substantive law and properly chose the seat of arbitration to ensure the application of suitable rules on the burden of proof.

Art 25(2) provides that the arbitral tribunal shall determine the “admissibility, relevance, materiality and weight of the evidence”. Not all arbitration rules provide an express provision to this effect. Nonetheless, such power is, of course, entrusted to arbitral tribunals by the relevant law applicable to the arbitration proceedings (see Art 19(2) UNCITRAL Model Law on International Commercial Arbitration). The inclusion of an express reference to the tribunal’s power to “weigh” the evidence is to be welcomed: It reminds tribunals to evaluate the evidence thoroughly and to provide a reasoned explanation of the weight accorded to each item.

Art 25(3) stipulates that the tribunal has the power “to invite” one party to adduce additional evidence. It is unclear why such a term was chosen, which is collaborative in tone and suggests a choice of the parties. Other arbitration rules expressly empower tribunals to “require” a party to adduce evidence (eg Art 27(3) UNCITRAL Arbitration Rules) or to “order” the production of documents or other evidence (eg Art 50(b) WIPO Arbitration Rules).

By empowering tribunals merely to “invite” parties to adduce evidence it remains unclear what follows in the event that a party chooses not to follow the “invitation”. The drafters may therefore wish to consider the approach taken in other rules and spell out the potential consequences of a failure to comply or make it clear that a failure to comply amounts to a violation of a procedural order. With such a change, it would, for instance, be clearer to the parties that a tribunal may draw adverse inferences in circumstances where documents were not provided.

Document Production 

Document production is a standard feature of international arbitration proceedings. Thus a party may, with the assistance of the tribunal, request the production of documents in the possession of the opposing side. The Draft Rules accordingly provide for an express rule in Art 31(1). In that respect it follows the United Patent Court (UPC) Rules of Procedure (Rule 190) which also expressly provide for parties to make reasoned document production requests. Whether that express rule is sufficient for FRAND disputes that appear particularly relevant for the Centre, however, seems more than questionable given the lack of guidance on what documents should generally be produced.

Most other arbitration institutions do not provide any detailed provisions on document production within their rules. The power to order document production is usually derived from the tribunal’s broad power to determine the arbitration procedure (Art 20(2) Draft Rules) and to establish the facts of the case, including to “invite” production of (additional) evidence (see Art 25(3)). Given the absence of specific provisions in most arbitration rules, international arbitration tribunals very often use the IBA Rules on the Taking of Evidence (the IBA Rules) as guidance on any document production process. Occasionally, the parties even agree or tribunals determine that the IBA Rules are binding.

In the present case, the Draft Rules have chosen a different approach. They have included a provision on document production within the Draft Rules themselves that is rather detailed in certain aspects. The drafters seem to have relied on the IBA Rules in many respects, but chosen to deviate from the rules on occasion. The deviations from the IBA Rules generally tend towards allowing broader document production than contemplated by the IBA Rules.

For instance, although the IBA Rules require that documents are “relevant to the case and material to its outcome”, there is no requirement under Art 31 Draft Rules that the requested document must be “material to the outcome” of the dispute; it suffices that the document is “relevant to an issue in dispute”. 

Moreover, the Draft Rules require merely a “brief explanation” that the requirements for the production of documents are met. It is again unclear why the drafter have chosen to depart from the IBA Rules requirement that the application needs to be justified in “sufficient detail”, and it seems, at least, possible that they thereby sought to impose a less onerous requirement on the applicants. 

The Draft Rules have also omitted “commercial confidentiality” as an objection to document requests. They have, thus, again departed from the IBA Rules. An explanation for this omission might be that the drafters saw no need for an objection based on confidentiality because Art 31(4) Draft Rules allows the tribunal to order the application of an “appropriate confidentiality regime”. It is noteworthy that the IBA Rules do contain a provision on confidentiality protective orders (Art 9(5) IBA Rules) while still allowing confidentiality objections that one side may raise against the document production requests. 

Art 31(3) Draft Rules also lacks any express consideration of procedural economy, proportionality, fairness or equality of the parties as a ground for an objection (other than Art 3(5), 9(2)g IBA Rules). Given that the IBA Rules seem to have been considered by the drafters, it seems likely that they omitted this particular ground for an objection intentionally. Against this background, it thus remains to be clarified whether these aspects can be taken into account by a tribunal at all or whether they would need to be considered as part of the tribunal’s general exercise of its discretion (see Art 31(1) Draft Rules) or otherwise.

Despite the Centre’s goal to provide “provisions addressing complex issues such as disputes involving Standard Essential Patents (SEPs) and FRAND licensing terms” the Draft Rules do not contain any specific (early) disclosure mechanism for FRAND licensing disputes, that would set out a framework governing whether and when SEP holders or licensees have to provide transparency about portfolio valuation, comparables or other datapoints relevant for the respective licensing dispute. Tribunals may discuss with the parties early “potential document production requests” in the case management conference (Art 22(5) Draft Rules) and a tribunal may then indeed make such an early document production order. But this is in the end up to a tribunal’s discretion. Going forward, some additional guidance would likely be helpful to the parties and tribunals, and help built up trust in the Centre’s arbitration process.

Next steps and need for clarification?

In summary, Art 25 Draft Rules concerns “evidence” and contains three paragraphs. The paragraph on the burden of proof as drafted is unlikely to have any practical relevance as it refers the parties and the tribunal to the applicable law. The paragraph dealing with the weighing of evidence is fairly standard and arguably an improvement on other rules that do not expressly identify this power and duty of the tribunal. The final paragraph of Art 25 of the Draft Rules, which contemplates that the parties may merely be “invited” to adduce additional evidence, could perhaps be clarified by using language reflecting the tribunal’s authority (eg parties may be “required” or “ordered” to adduce additional evidence) or setting out the consequences if a party declines the “invitation”. 

As concerns document production in Art 31 of the Draft Rules, the fundamental point that ought to be clarified by the drafters is why they have chosen to include an express and detailed provision within the rules but have decided not to include more guidance for FRAND disputes which would appear to be one of the main reasons to include an express and detailed provision on document production in the first place. The other matter that could be explained is why the drafters chose to depart from the IBA Rules in certain aspects. With that clarification, future users of these rules will better know how to use the document production mechanism in practice.