Ad hoc arbitration is a form of arbitration in which the parties themselves organise and administer the entire proceedings, without delegating administrative oversight to a permanent arbitral institution. There is no secretariat, no institutional fee schedule, and no pre-set procedural rulebook imposed from outside - the parties and their chosen arbitrators design the process themselves. For international businesses, this creates both significant flexibility and meaningful responsibility: the outcome depends heavily on how carefully the arbitration agreement and procedural framework are drafted from the outset. This guide covers the legal definition of ad hoc arbitration, how it differs from institutional arbitration, the procedural framework parties typically adopt, the practical risks and advantages, and the scenarios in which it is the right choice.
Ad hoc arbitration is defined as an arbitral process that is not administered by an arbitral institution. The term "ad hoc" derives from Latin, meaning "for this specific purpose." In legal practice, it describes a tribunal constituted and operated solely for the resolution of a particular dispute, after which it ceases to exist.
The concept is recognised under the United Nations Commission on International Trade Law (UNCITRAL) Model Law on International Commercial Arbitration, which most major arbitration-friendly jurisdictions have adopted in whole or in part. The UNCITRAL Arbitration Rules, first published in the 1970s and subsequently revised, were designed specifically for ad hoc proceedings and remain the most widely used procedural framework in this context. Parties who choose ad hoc arbitration frequently incorporate the UNCITRAL Rules by reference in their arbitration clause, giving the process a structured backbone without submitting to any institution.
In contrast to institutional arbitration - where bodies such as the ICC, LCIA or SIAC administer the case, appoint arbitrators if needed, scrutinise awards, and charge administrative fees - ad hoc arbitration places all of those functions directly in the hands of the parties and the tribunal. The arbitrators themselves manage correspondence, set timetables, and issue procedural orders without institutional supervision.
A non-obvious requirement in ad hoc proceedings is the need to designate an appointing authority in the arbitration agreement. If the parties cannot agree on an arbitrator, someone must have the power to make the appointment. The UNCITRAL Rules allow parties to name any person or body as appointing authority. In the absence of a designation, the Secretary-General of the Permanent Court of Arbitration (PCA) in The Hague serves as the default appointing authority under those rules.
Ad hoc arbitration shares the fundamental legal characteristics of all arbitration: it is a private, consensual, and binding method of resolving disputes outside the state court system. The arbitral award is final and enforceable in over 170 countries under the New York Convention on the Recognition and Enforcement of Foreign Arbitral Awards.
Several features distinguish ad hoc proceedings legally:
The legal validity of an ad hoc arbitration agreement depends on it satisfying the formal requirements of the New York Convention: the agreement must be in writing and must concern a dispute capable of settlement by arbitration under the law of the seat. Courts in most jurisdictions interpret "in writing" broadly to include electronic communications.
The core distinction is administrative control. In institutional arbitration, a permanent body - the institution - manages the case from filing to award. It collects fees, maintains a list of arbitrators, sets timelines, and provides a secretariat. In ad hoc arbitration, none of those services exist unless the parties create them.
This distinction has several practical consequences. First, costs in ad hoc proceedings can be lower because there are no institutional administrative fees, which in large cases can reach significant sums. However, the parties bear the full cost of any logistical support they need, including hearing rooms, transcription services, and document management platforms. In practice, the cost advantage of ad hoc arbitration is most pronounced in mid-size disputes where institutional fees would be disproportionate.
Second, speed and flexibility differ materially. Institutional rules impose fixed deadlines - for example, a time limit for constituting the tribunal or rendering the award. Ad hoc proceedings have no such external constraints unless the parties build them in. This can accelerate resolution when parties cooperate, but it can also allow a recalcitrant party to delay proceedings indefinitely by refusing to participate in tribunal constitution or procedural steps.
Third, the quality of arbitrator selection is entirely the parties'; responsibility. Institutions maintain vetted rosters and apply appointment criteria. In ad hoc arbitration, parties must conduct their own due diligence on proposed arbitrators, checking for conflicts of interest, relevant expertise, and availability.
A common mistake made by parties unfamiliar with ad hoc proceedings is drafting a bare arbitration clause - one that says only "disputes shall be resolved by arbitration" without specifying the seat, the rules, the number of arbitrators, or the appointing authority. Such a clause is technically valid but creates enormous procedural uncertainty if a dispute arises.
Because there is no institution to impose a procedural framework, parties must either adopt a recognised set of rules by reference or agree on bespoke procedures. The UNCITRAL Arbitration Rules are the standard choice for international commercial disputes. They cover the full lifecycle of proceedings: notice of arbitration, constitution of the tribunal, pleadings, evidence, hearings, and the form of the award.
The process typically unfolds in the following stages. The claimant serves a notice of arbitration on the respondent, identifying the dispute, the relief sought, and the proposed arbitrator. The respondent nominates a co-arbitrator. The two party-appointed arbitrators then select a presiding arbitrator, or the appointing authority does so if they cannot agree. Once the tribunal is constituted, it issues procedural orders establishing the timetable for written submissions, document production, and the hearing.
Interim measures present a particular challenge in ad hoc arbitration. Before the tribunal is constituted, there is no arbitral body to grant emergency relief. Parties must apply to the courts of the seat for interim injunctions or asset freezing orders. This is one area where institutional arbitration - which increasingly offers emergency arbitrator procedures - has a practical advantage.
The seat of arbitration is a legal concept, not necessarily a physical location. It determines which national courts supervise the arbitration and which procedural law governs matters not covered by the parties'; agreement. Parties frequently choose seats in jurisdictions with arbitration-friendly courts and modern arbitration legislation, such as England, Switzerland, Singapore, or France.
If your business is considering an ad hoc clause for a significant contract, we can help structure the setup correctly the first time. Contact us at info@vlolawfirm.com to discuss the appropriate framework for your transaction.
Ad hoc arbitration suits certain commercial situations better than institutional alternatives. Understanding those scenarios helps parties make an informed choice at the contract drafting stage.
Scenario one: a long-term infrastructure contract between two sophisticated parties. Two large corporations entering a multi-year construction or energy project may prefer ad hoc arbitration because they want maximum control over the process, they have experienced legal teams capable of managing proceedings, and they wish to avoid the administrative fees of a major institution. They incorporate the UNCITRAL Rules, designate the PCA as appointing authority, and choose a neutral seat. In this context, ad hoc arbitration delivers cost efficiency and procedural flexibility without meaningful loss of quality.
Scenario two: a mid-market cross-border supply agreement. A mid-size manufacturer and a foreign distributor include an ad hoc clause in their distribution agreement. When a dispute arises, the respondent refuses to nominate an arbitrator. Because the parties designated an appointing authority in their clause, the authority steps in and constitutes the tribunal. The proceedings continue despite the respondent';s non-cooperation. This illustrates why a well-drafted appointing authority designation is not optional - it is the mechanism that keeps ad hoc arbitration functional when one party becomes obstructive.
Many parties underestimate the importance of the governing law clause alongside the arbitration clause. The governing law determines the substantive rights of the parties; the arbitration clause determines how disputes about those rights are resolved. In ad hoc arbitration, where there is no institution to flag inconsistencies, a mismatch between the two can create jurisdictional complications that delay proceedings significantly.
Another practical consideration is the enforceability of the award. Ad hoc awards are enforceable under the New York Convention on the same basis as institutional awards, provided the arbitration agreement and proceedings comply with the Convention';s requirements. Courts in enforcing jurisdictions do not distinguish between ad hoc and institutional awards when assessing enforceability.
The advantages of ad hoc arbitration are well established in international practice. Parties retain full control over the process, can tailor procedures to the specific dispute, and avoid institutional overhead. For parties with experienced legal counsel, this control is a genuine benefit.
The risks are equally real. Without institutional support, proceedings are vulnerable to delay tactics by an uncooperative party. The absence of award scrutiny means errors in the award - procedural or substantive - are harder to catch before the award is issued. And the entire process depends on the quality of the arbitration clause drafted before any dispute arises.
Common drafting mistakes include:
In practice, founders and contract managers should treat the arbitration clause as a standalone agreement requiring the same attention as the main commercial terms. A poorly drafted clause does not become apparent until a dispute arises - at which point correcting it is expensive and sometimes impossible.
The UNCITRAL Model Law, adopted in various forms by jurisdictions including Germany, Canada, Australia, Singapore, and many others, provides the legislative backdrop against which ad hoc proceedings at those seats are conducted. Familiarity with the Model Law provisions on tribunal jurisdiction, interim measures, and award challenge is essential for any party contemplating ad hoc arbitration.
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Is an ad hoc arbitration award enforceable internationally?
Yes. An ad hoc arbitral award is enforceable in all countries that have ratified the New York Convention, provided the arbitration agreement was in writing, the proceedings were conducted in accordance with that agreement, and the award does not violate the public policy of the enforcing state. Courts in enforcing jurisdictions apply the same legal test to ad hoc and institutional awards. The key practical requirement is that the arbitration agreement and proceedings must comply with the Convention';s formal requirements, which means the seat and the procedural rules must be clearly identified in the clause. A well-drafted ad hoc clause produces an award that is just as enforceable as one issued under ICC or LCIA rules.
How long does ad hoc arbitration typically take, and what does it cost?
Timelines vary considerably depending on the complexity of the dispute, the cooperation of the parties, and the procedural choices made. A straightforward commercial dispute can be resolved in six to twelve months; complex multi-party cases may take two to three years. Because there are no institutional fees, the direct costs of ad hoc arbitration are generally lower than institutional proceedings of equivalent size - the main cost drivers are arbitrator fees, legal counsel fees, and logistical expenses such as hearing venues and transcription. Arbitrator fees in ad hoc proceedings are negotiated directly with the tribunal and can be structured as hourly rates or lump sums. Parties should budget for these costs explicitly in the arbitration clause or in a separate fee agreement at the outset of proceedings.
When should a business choose ad hoc arbitration over institutional arbitration?
Ad hoc arbitration is most appropriate when both parties are sophisticated, have experienced legal representation, and want maximum procedural flexibility at lower administrative cost. It works well for large infrastructure, energy, or long-term commercial contracts where the parties have the resources to manage proceedings independently. Institutional arbitration is generally preferable for parties with less arbitration experience, for disputes where emergency relief may be needed quickly, or where the reputational assurance of an established institution adds value to the process. The choice is not binary: parties can adopt a recognised set of rules such as the UNCITRAL Rules in an ad hoc context, giving themselves procedural structure without institutional administration.
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Ad hoc arbitration is a powerful and flexible dispute resolution mechanism for international commercial parties who are willing to invest in careful drafting and competent legal management. Its defining feature - the absence of institutional administration - is both its main advantage and its principal risk. Used correctly, it delivers cost efficiency, procedural control, and enforceable awards recognised worldwide. Used carelessly, it produces procedural gridlock and unenforceable outcomes.
VLO Law Firms advises international clients on ad hoc arbitration and international dispute resolution. We can assist with drafting arbitration clauses, selecting the appropriate procedural framework, constituting tribunals, and managing ad hoc proceedings from notice to award. To request a consultation, contact: info@vlolawfirm.com