1. What Is a Single Arbitration Under Multiple Contracts
A single arbitration under multiple contracts is an arbitration in which the claimant brings claims arising under two or more separate contracts in one proceeding from the outset. Rather than filing separate Notices of Arbitration for each contract, the claimant files one Notice covering all the related claims.
This is distinct from:
- Consolidation, which combines arbitrations that have already been commenced separately
- Joinder, which adds parties to an existing arbitration
For more on Consolidation and Joinder, refer to the articles linked above on each of them.
The multiple contracts mechanism allows related disputes to be packaged together at the start, avoiding the need for consolidation later.
2. Reasons for Parties to Seek Multiple Contracts
Commencing a single arbitration under multiple contracts offers advantages:
Efficiency
One arbitration is more efficient than several. There is one tribunal, one procedural timetable, one set of submissions, and one hearing
Cost savings
Arbitrator fees, institutional fees, and legal costs are substantially lower for one arbitration than for multiple parallel proceedings.
Consistency
A single tribunal deciding all related claims eliminates the risk of inconsistent findings on overlapping facts or legal issues.
Practical necessity
In many cases, the claims under different contracts are so interrelated that they cannot sensibly be separated. The same factual matrix underlies the disputes; the same witnesses will give evidence; the same documents are relevant.
However, multi-contract arbitration is only available where the arbitration agreements are compatible and the claims meet certain requirements. If the agreements are incompatible (for example, if they specify different institutions or different seats) a single arbitration may not be possible.
3. When a Single Arbitration Is Permitted Under the SIAC Rules
Rule 6 of the SIAC Rules (7th Edition) permits a party to commence a single arbitration under multiple contracts where:
- All parties have agreed to the single arbitration; or
- All the claims arise out of the same transaction or series of transactions, and the Court of Arbitration finds that:
- The arbitration agreements under which the claims are made are compatible; and
- A common question of law or fact arises under each arbitration agreement
The second ground requires all three elements to be satisfied:
- Same transaction or series of transactions
The contracts must be related – typically part of the same project, deal, or commercial relationship. Unrelated contracts between the same parties do not qualify merely because they happen to involve the same parties.
- Compatible arbitration agreements
The arbitration agreements must be capable of being applied together. This is discussed in detail below in Section 4.
- Common question of law or fact
There must be at least one issue of law or fact that is common to the claims under each contract. This ensures that there is a genuine reason to hear the claims together.
| Ground | Requirements |
| All parties agree | Consent of all parties to a single arbitration under multiple contracts |
| Same transaction + compatible agreements + common questions | Claims arise from same transaction or series of transactions; arbitration agreements are compatible; common question of law or fact |
4. What “Compatible Arbitration Agreements” Means
Compatibility is the threshold requirement for multi-contract arbitration under Rule 6.1(b). If the arbitration agreements are not compatible, the Court of Arbitration will not permit a single arbitration, and the claimant will need to commence separate proceedings.
Factors indicating compatibility:
- Same arbitral institution.
If all contracts specify SIAC arbitration, this strongly supports compatibility.
- Same seat.
If all contracts specify the same seat (e.g., Singapore), the procedural law governing the arbitrations will be the same.
- Same procedural rules.
If all contracts specify the SIAC Rules (or do not specify rules, in which case the SIAC Rules apply by default), the procedural framework will be consistent.
- Same or compatible tribunal appointment mechanisms.
If the contracts all provide for a sole arbitrator, or all provide for three arbitrators with the same appointment mechanism, there is no conflict.
- No conflicting provisions.
The contracts should not contain provisions that contradict each other in ways that cannot be reconciled.
Factors indicating incompatibility:
- Different arbitral institutions.
A contract specifying SIAC arbitration and another specifying ICC arbitration cannot be the subject of a single SIAC arbitration.
- Different seats.
Contracts specifying Singapore and Hong Kong as seats may be incompatible, as different courts would have supervisory jurisdiction.
- Different procedural rules with conflicting provisions.
If one contract specifies expedited procedure and another excludes it, there may be a conflict.
- Confidentiality restrictions.
If one contract contains strict confidentiality provisions that would prevent information from being shared with parties to another contract, compatibility may be in question.
| Compatible | Potentially Incompatible | Incompatible |
| All contracts specify SIAC, Singapore seat, SIAC Rules | Contracts specify SIAC but different seats (e.g., Singapore and Hong Kong) | One contract specifies SIAC, another specifies ICC |
| Contracts specify SIAC without specifying seat (Singapore is default) | Contracts have different tribunal appointment mechanisms | Contracts specify different seats with mandatory local procedural law |
| Minor wording differences in otherwise identical clauses | One contract includes confidentiality provisions, another does not | Contracts contain express provisions prohibiting multi-contract arbitration |
5. Steps to Commence a Single Arbitration Under Multiple Contracts
Step 1: Assess compatibility
Before filing, analyse the arbitration agreements in each contract:
- Are they all SIAC agreements?
- Do they specify the same seat?
- Are there any conflicting provisions?
If the agreements are clearly compatible, proceed. If there are potential issues, consider whether the Court of Arbitration is likely to find them compatible or whether separate arbitrations are the safer course.
Step 2: Identify the transaction and common questions
Articulate how the contracts are related (same project, same transaction, same commercial relationship) and identify at least one common question of law or fact that arises under each contract.
Step 3: Prepare the Notice of Arbitration
A Notice of Arbitration commencing a multi-contract arbitration must:
- Identify all the contracts under which claims are made
- Include copies of all arbitration agreements
- Explain why the requirements of Rule 6 are satisfied (same transaction, compatible agreements, common questions)
- Set out the claims under each contract
- State the relief sought
Step 4: Submit to SIAC
Submit the Notice of Arbitration with the required registration fee. SIAC will notify all respondents and invite a response.
Step 5: Court of Arbitration determination
Unless all parties agree to the single arbitration, the Court of Arbitration will determine whether Rule 6.1(b) is satisfied. This is a threshold determination. If the Court finds the requirements are met, the arbitration proceeds as a single proceeding. If not, the Court may direct that separate arbitrations be commenced.
6. If You Are Defending a Multi-Contract Arbitration
If you have received a Notice of Arbitration asserting claims under multiple contracts, you have several options.
Challenge multi-contract jurisdiction
You may argue that the requirements of Rule 6 are not satisfied:
- The arbitration agreements are not compatible
- The claims do not arise from the same transaction or series of transactions
- There is no common question of law or fact
If the Court of Arbitration agrees, it may direct that separate arbitrations be commenced. If the arbitration proceeds and a tribunal is constituted, you may renew the jurisdictional challenge before the tribunal.
Defend on the merits
Even if multi-contract jurisdiction is established, you retain all substantive defences under each contract. The tribunal will determine each claim on its merits.
Counterclaim under multiple contracts
If you have claims of your own under the same contracts (or other related contracts with compatible arbitration agreements), you may file counterclaims in the same arbitration. Rule 6 permits a respondent to assert claims under multiple contracts in the same way as a claimant.
| Option | When to Use |
| Challenge compatibility | The arbitration agreements have different institutions, seats, or conflicting provisions |
| Challenge same transaction | The contracts are unrelated; they do not arise from the same project or commercial relationship |
| Challenge common questions | The claims under each contract raise distinct issues with no meaningful overlap |
| Defend on the merits | Accept multi-contract jurisdiction but dispute the claims substantively |
| Counterclaim | You have claims under the same or related contracts |
7. How the Court of Arbitration and Tribunal Approach Multi-Contract Claims
The Court of Arbitration’s role
The Court of Arbitration makes the initial determination on whether a single arbitration under multiple contracts is permitted. This is an administrative determination, not a final ruling on jurisdiction.
The Court applies the requirements of Rule 6: compatibility, same transaction, and common questions. If satisfied, the arbitration proceeds. If not, the Court may direct that separate arbitrations be commenced.
The tribunal’s role
Once constituted, the tribunal has jurisdiction to determine all claims properly before it, including any challenges to jurisdiction under specific contracts.
If a respondent argues that the tribunal lacks jurisdiction over claims under a particular contract (e.g., because that contract’s arbitration agreement is not compatible), the tribunal will rule on that objection. The tribunal may:
- Reject the objection and proceed with all claims
- Uphold the objection and decline jurisdiction over claims under that contract
- Bifurcate the proceedings to address jurisdiction first
The tribunal’s jurisdictional ruling can be challenged in subsequent setting aside or enforcement proceedings, but courts are generally reluctant to disturb tribunal findings on such matters.
8. Relationship with Joinder and Consolidation
The SIAC Rules provide three mechanisms for addressing related disputes:
| Mechanism | What It Does | When to Use | Key Requirement |
| Multiple Contracts (Rule 6) | Commence one arbitration covering claims under several contracts | At the outset, when disputes arise under related contracts | Compatible arbitration agreements |
| Joinder (Rule 7) | Add a party to an existing arbitration | When a non-party should be included after arbitration has commenced | Party is prima facie bound or consents |
| Consolidation (Rule 8) | Combine separate arbitrations into one | When related arbitrations are pending separately | Compatible agreements + common issues or same transaction |
These mechanisms can be used together. For example:
- A claimant commences a single arbitration under multiple contracts (Rule 6)
- The claimant then applies to join an additional party that is bound by one of those contracts (Rule 7)
- Separately, another arbitration is pending between related parties, and a party applies to consolidate it with the first arbitration (Rule 8)
9. Drafting Considerations
The ability to commence a single arbitration under multiple contracts depends on how the arbitration agreements are drafted.
Facilitating multi-contract arbitration
If a transaction involves multiple agreements and the parties anticipate that disputes may be interrelated:
- Use identical arbitration clauses in all contracts. This ensures compatibility.
- Specify the same seat and institution. Do not vary these elements across contracts.
- Include an express multi-contract provision. For example: “The parties agree that claims under this agreement may be brought together with claims under [specify related agreements] in a single arbitration.”
- Avoid conflicting provisions. Review all contracts to ensure there are no inconsistent requirements regarding procedure, confidentiality, or tribunal composition.
Restricting multi-contract arbitration
If a party wishes to ensure that disputes under different contracts are resolved separately:
- Include an express provision requiring separate arbitration for each contract
- Use different arbitration provisions in different contracts (though this creates complexity)
- Include strict confidentiality provisions that would prevent consolidation of information
In practice, parties often benefit from the ability to resolve related disputes together. Overly restrictive drafting may create inefficiencies if disputes arise that genuinely require coordinated resolution.
Conclusion
The SIAC Rules permit a single arbitration under multiple contracts where the arbitration agreements are compatible, the claims arise from the same transaction or series of transactions, and a common question of law or fact exists. This mechanism promotes efficiency and consistency in resolving related commercial disputes.
For claimants, the key is ensuring that the requirements of Rule 6 are satisfied before filing. For respondents, the focus is on whether multi-contract jurisdiction should be challenged and, if not, how to defend the claims on their merits.