ICDPASO Commercial Arbitration Rules Interpretation Series 33“Close of Hearing”

In arbitral case management, a “declaration of closure of the hearing phase” signifies that the case moves from the hearing stage of “submission of evidence—examination of evidence—argument” into the relatively closed stage of the tribunal’s internal deliberations and drafting of the award. If the timing of closure is mishandled, it may, at a minimum, lead to delays in the issuance of the award and increased costs; at a maximum, it may be questioned in subsequent set-aside or enforcement review on the ground that a party was not afforded a “reasonable opportunity to present its case,” thereby creating the risk of being characterized as a “procedural violation of statutory due process” [one of the statutory grounds for setting aside an award under the newly revised Arbitration Law of the People’s Republic of China (the “New Arbitration Law”)].

Article 33 of the International Commercial Dispute Prevention and Settlement Organization (ICDPASO) Commercial Arbitration Rules (the “Rules”) (the “Article 33”) establishes a two-paragraph framework through “closure of the hearing phase” and “reopening the hearing where necessary (hereinafter, ‘reopening’)”. It both locks in procedural boundaries through “closure” and preserves flexibility for correction and supplementation through “reopening,” thereby balancing efficiency and due process.

I. Text of Article 33 of the Rules

Article 33. Close of Hearing

1. If, after consulting the parties, the Arbitral Tribunal considers that it is not necessary to provide further substantive evidence or further statements on the disputed issues to be arbitrated, it may announce the close of hearing.

2. If, due to special circumstances, the Arbitral Tribunal may, as it deems necessary, reopen the hearing before making the award at its own discretion or upon application by either party.

II. Clause-by-Clause Commentary on Article 33

Paragraph (1) Triggering Conditions and Procedural Propriety for Closing the Hearing Phase

1. Textual Analysis

This paragraph may be deconstructed into four progressive elements.

Procedural prerequisite: the tribunal must “consult the parties.” This requirement proceduralizes and records whether the parties have been sufficiently heard and have had the opportunity to present evidence, reducing the risk of challenges alleging “sudden closure” or deprivation of the right to be heard.

Substantive assessment standard: the tribunal, upon evaluation, considers that for the disputed issues to be decided, it is not necessary to provide further substantive evidence or further statements. The qualifier “substantive” is critical: it does not absolutely prohibit supplementary materials (in practice, depending on the tribunal’s specific directions, post-hearing submissions or documents may still be permitted), but emphasizes that the core issues necessary for the award have been sufficiently established on the evidentiary record.

Discretionary nature: the wording “may announce” indicates that closure falls within the tribunal’s case-management discretion, rather than constituting a mandatory duty.

Object of closure: “close of hearing ” refers to the end of the hearing, evidence-taking, examination, and argument stages, and is distinct from circumstances that terminate the proceedings as a whole, such as withdrawal of claims or settlement by the parties.

Institutional features and advantages: the dual threshold of “consultation + assessment of substantive sufficiency” both safeguards the parties’ procedural participation rights and provides the tribunal with a clear recommended “closing point,” helping to curtail ineffective evidence-taking and tactical supplemental submissions.

2. Comparative law perspective

The UNCITRAL Arbitration Rules (2021) are structurally similar to this paragraph: the tribunal may ask the parties whether there is any remaining evidence, witnesses, or submissions to be presented; if not, it may declare the hearings closed.① The SIAC Rules (2025) adopt a more rigid approach to “closure,” requiring that, after the last directed oral hearing or written submission, and once the tribunal confirms that the parties have no “relevant and material” evidence or submissions, closure be declared in writing.② The ICC Rules (2021) use the concept of “Closing of the Proceedings,” requiring that the proceedings be declared closed as soon as possible after the last hearing or the last authorized written submission, and that the parties be informed at the same time of the expected date for submission of the draft award;③ the HKIAC Rules (2024) further introduce a “cap on the time-point of closure,” requiring that the proceedings (or phase) be declared closed no later than 45 days after the last substantive oral or written submission, and maintaining linkage between the timetable for the award and the closure milestone.④

3. Practical guidance

Seize the “final window.” When the tribunal consults the parties on whether any further evidence or submissions remain to be provided, this should be treated as a key procedural milestone. A brief but complete written response should clearly address: whether further evidence is needed; if so, explain its relevance, necessity, reasons for unavailability to date, and the expected timing; and whether supplemental submissions are needed on applicable law, quantum calculations, etc.

Avoid “generalized reservation of rights.” If a party responds merely by broadly stating it “reserves the right to submit further evidence,” without specifying scope, the response is easily regarded as lacking substance, and later submissions may be treated as procedural delay.

Paragraph (2) Triggering Conditions for Reopening and Procedural Continuity

1. Textual Analysis

This paragraph may be deconstructed into three progressive elements.

Triggering requirement: “special circumstances” and “necessary.” “Special circumstances” underscores the exceptional nature of reopening, preventing it from becoming a routine “second-round evidence channel”; “necessary” emphasizes strict application and the principle of proportionality.

Initiation pathways: the tribunal may decide “at its own discretion” or may decide “upon application by either party.” This reflects a parallel structure in which ex officio correction and party-initiated relief coexist.

Temporal boundary: reopening must occur “before making the award.”

2. Comparative law perspective

This paragraph is similar to the UNCITRAL Arbitration Rules (2021), which likewise limit reopening to “exceptional circumstances” and allow the tribunal to reopen before the award either on its own initiative or upon application.⑤ The SIAC Rules (2025) similarly permit reopening before the award, and require that a reopening decision be notified in writing to the parties and the institution, enhancing traceability. ⑥The HKIAC Rules (2024) also provide that the tribunal may reopen the proceedings before the award.⑦ While the ICC Rules (2021) adopt the principle that, after the proceedings are closed, materials should generally no longer be submitted, they preserve an exception where the tribunal “requests or authorizes” further submissions—substantively leaving room for “reopening where necessary,” though framed more as “permission to submit” rather than “reopening the hearing.⑧”

3. Practical guidance

An application to reopen should be supported by evidence. It is recommended to submit verifiable materials demonstrating the “special circumstances” and “necessity,” and to explain a reasonable basis for why the relevant evidence or grounds could not have been presented before closure (and not due to failure to exercise rights diligently).

Limit the objective of reopening. The application should be focused, for example, on “reopening for a short hearing on a key issue for limited cross-examination or expert questioning,” and should propose an operational plan (e.g., duration, witness list, and issue/question list) to increase the likelihood that the tribunal will grant reopening.

III. Conclusion

Through Paragraph (1), Article 33 follows the progressive path of “consultation—assessment that no substantive supplementation is necessary—declaration of closure,” transforming a procedural milestone into a traceable case-management record and setting a clear starting point for deliberations on the award; Paragraph (2), by imposing the stringent condition of “special circumstances and true necessity,” preserves a flexible corrective space for reopening before the award is rendered, achieving a dynamic balance between efficiency and due process. In light of the evolving approaches of mainstream rules such as UNCITRAL, ICC, SIAC, and HKIAC, Article 33 is highly compatible with the internationally prevalent “closure—exceptional reopening” paradigm. It also better enables the tribunal, through traceable procedural orders and timetables, to effectively mitigate set-aside risks based on allegations of “insufficient opportunity to be heard” or “procedural illegality,” thereby enhancing the stability and enforceability of the award.

①UNCITRAL Arbitration Rules (2021) art 31.1, which provides that: “The arbitral tribunal may inquire of the parties if they have any further proof to offer or witnesses to be heard or submissions to make and, if there are none, it may declare the hearings closed.”

②SIAC Rules（2025）art.42.1, which provides that: “42.1 The Tribunal shall, as soon as practicable after the last directed oral or written submissions in respect of matters to be decided in an award, and upon being satisfied that the parties have no further relevant and material evidence to produce or submissions to make with respect to such matters, declare the proceedings closed. The Tribunal’s declaration that the proceedings are closed shall be in writing and communicated to the parties and the SIAC Secretariat.”

③ICC 2021 Arbitration Rules art. 27 Closing of the Proceedings and Date for Submission of Draft Awards, which provided that: “As soon as possible after the last hearing concerning matters to be decided in an award or the filing of the last authorized submissions concerning such matters, whichever is later, the arbitral tribunal shall:

a) declare the proceedings closed with respect to the matters to be decided in the award; and

b) inform the Secretariat and the parties of the date by which it expects to submit its draft award to the Court for approval pursuant to Article 34.

After the proceedings are closed, no further submission or argument may be made, or evidence produced, with respect to the matters to be decided in the award, unless requested or authorized by the arbitral tribunal.”

④HKIAC 2024 Administered Arbitration Rules art 31.1 , which provided that: “When it is satisfied that the parties have had a reasonable opportunity to present their case, whether in relation to the entire proceedings or a discrete phase of the proceedings, and no later than 45 days from the last directed substantive oral or written submissions in respect of the entire proceedings or the discrete phase of the proceedings (excluding submissions on costs under Article 34), the arbitral tribunal shall declare the proceedings or the relevant phase of the proceedings closed. Thereafter, no further submissions or arguments may be made, or evidence produced in respect of the entire proceedings or the discrete phase, as applicable, unless the arbitral tribunal reopens the proceedings or the relevant phase of the proceedings in accordance with Article 31.4.”

⑤UNCITRAL Arbitration Rules (2021) art 31.2, which provides that: “The arbitral tribunal may, if it considers it necessary owing to exceptional circumstances, decide, on its own initiative or upon application of a party, to reopen the hearings at any time before the award is made.”

⑥SIAC Rules（2025）art.42.2, which provides that: “The Tribunal may, on its own motion or upon application of a party but before any award is made, reopen the proceedings. The Tribunal’s decision that the proceedings are to be reopened shall be in writing and communicated to the parties and to the SIAC Secretariat.”

⑦HKIAC 2024 Administered Arbitration Rules art 31.4 , which provided that: “The arbitral tribunal may, if it considers it necessary, decide, on its own initiative or upon application of a party, to reopen the proceedings at any time before the award is made.”

⑧ICC 2021 Arbitration Rules art. 27 Closing of the Proceedings and Date for Submission of Draft Awards, which provided that: “............After the proceedings are closed, no further submission or argument may be made, or evidence produced, with respect to the matters to be decided in the award, unless requested or authorized by the arbitral tribunal.”