Multi-Party and Multi-Contract Arbitration in Turkey: Joinder and Consolidation

Introduction

Modern commercial transactions are rarely governed by a single agreement signed by only two companies. Construction, energy, mergers and acquisitions, infrastructure, distribution, banking, insurance, technology and maritime projects commonly involve several parties and a network of interconnected contracts.

A major construction project may include an employer, main contractor, subcontractors, designers, suppliers, guarantors and lenders. An acquisition may involve several sellers, the purchaser, the target company, a parent guarantor, an escrow agent and management shareholders. An energy investment may be structured through an EPC contract, equipment supply agreement, operation and maintenance agreement, power purchase agreement, financing documents and shareholders’ agreement.

When disputes arise, the same facts may generate claims under several contracts against different parties. The project owner may claim delay damages from the main contractor, while the main contractor seeks an indemnity from a subcontractor. A purchaser may bring warranty claims against several sellers, while the sellers claim payment from the escrow agent. A project company may allege that both the equipment supplier and operator contributed to a production failure.

Resolving each part of the dispute in a separate arbitration may create:

• Repeated evidence;
• Increased legal and expert costs;
• Inconsistent factual findings;
• Conflicting awards;
• Difficulty allocating responsibility;
• Delayed enforcement.

Multi-party and multi-contract arbitration in Turkey seeks to address these risks through procedural mechanisms such as claims under multiple contracts, joinder of additional parties and consolidation of related arbitrations.

However, efficiency cannot override consent. Arbitration exists because the relevant parties agreed to submit specified disputes to arbitration. A company cannot ordinarily be added to an arbitral proceeding merely because it belongs to the same corporate group, participated commercially in the project or possesses relevant evidence.

Joinder and consolidation must therefore balance four fundamental principles:

1. Consent to arbitration;
2. Compatibility of arbitration agreements;
3. Equal participation in tribunal constitution;
4. The right of every party to present its case.

This guide explains multi-party and multi-contract arbitration under Turkish law and the Istanbul Arbitration Centre Arbitration Rules, including:

• The difference between joinder and consolidation;
• Claims arising under multiple contracts;
• Addition of non-signatory parties;
• Compatibility of arbitration clauses;
• Tribunal appointment in multi-party proceedings;
• Parallel arbitration risks;
• Due process and jurisdictional objections;
• Drafting strategies;
• Annulment and enforcement of awards.

What Is Multi-Party Arbitration?

Multi-party arbitration is an arbitration involving more than one claimant, more than one respondent or both.

Examples include:

• One purchaser bringing claims against several sellers;
• Several consortium members claiming against an employer;
• A project company claiming against an EPC contractor and parent guarantor;
• Several shareholders pursuing claims against another shareholder;
• An insurer and insured jointly pursuing a responsible contractor;
• A main contractor and subcontractor facing claims from the employer.

Multi-party arbitration does not necessarily involve multiple contracts. Three sellers and one buyer may all be parties to the same share purchase agreement and the same arbitration clause.

The principal procedural issues commonly include:

• Whether all parties consented to the same arbitration;
• Which claims can be heard together;
• How the tribunal will be appointed;
• Whether parties aligned on the same side can agree on an arbitrator;
• Whether one party has a conflict with another party nominally on the same side;
• How costs will be allocated;
• Whether counterclaims and cross-claims are permitted.

What Is Multi-Contract Arbitration?

Multi-contract arbitration involves claims arising from or connected with more than one contract.

For example, a claimant may rely on:

• A construction contract;
• A guarantee;
• A settlement agreement;
• A variation protocol;
• A supply contract.

The claims may concern the same project, but the contracts may contain different arbitration clauses.

Multi-contract arbitration becomes more difficult where the agreements differ regarding:

• Arbitration institution;
• Seat;
• Language;
• Number of arbitrators;
• Appointment procedure;
• Governing law;
• Scope of arbitrable disputes;
• Fast-track procedure;
• Emergency arbitrator provisions.

The fact that several contracts form part of the same commercial transaction does not automatically make their arbitration clauses compatible.

What Is Joinder?

Joinder means adding an additional party to an existing arbitration.

For example, an arbitration may begin between an employer and contractor. One party may later request that:

• A subcontractor;
• A parent guarantor;
• An affiliated company;
• A shareholder;
• An assignee;
• A project manager

be added to the proceeding.

Joinder changes the personal scope of the arbitration. The proposed additional party will become subject to the tribunal’s jurisdiction and potentially bound by the final award.

For that reason, the first question is not whether adding the party would be efficient. The first question is whether that party consented to arbitration.

Possible legal bases may include:

• Signature of the arbitration agreement;
• A written accession agreement;
• Assignment of a contract containing the clause;
• Legal succession;
• Agency;
• Incorporation of the arbitration clause by reference;
• A separate written agreement concluded after the dispute arose.

Membership in the same group of companies or economic involvement in the same project should not by itself be treated as sufficient proof of consent.

What Is Consolidation?

Consolidation is the combination of two or more already pending arbitrations into a single arbitration.

Before consolidation, each case has been commenced separately. Following consolidation, the claims are administered and decided within one proceeding.

For example:

• Arbitration A concerns delay claims under an EPC contract;
• Arbitration B concerns performance claims under an equipment supply contract;
• Arbitration C concerns a parent-company guarantee.

If the applicable rules and arbitration agreements permit, the three proceedings may potentially be consolidated.

Consolidation differs from joinder because consolidation combines proceedings, while joinder adds a person to one existing proceeding.

Turkish Legal Framework

Turkey-seated arbitration is governed primarily by two legislative regimes.

Domestic arbitration

Articles 407 to 444 of the Turkish Code of Civil Procedure apply to disputes:

• Seated in Türkiye; and
• Not containing the foreign element defined under the International Arbitration Law.

Article 412 defines the arbitration agreement as an agreement to submit all or part of an existing or future contractual or non-contractual dispute to arbitration. It requires written form and recognises incorporation by reference where a document containing the arbitration clause is intended to become part of the main contract.

International arbitration

International Arbitration Law No. 4686 applies principally where:

• The dispute contains a statutory foreign element; and
• The seat is in Türkiye;

or where the parties or tribunal select the statute within its scope.

Article 4 similarly requires a written arbitration agreement and recognises incorporation by reference. The statute also identifies several circumstances creating a foreign element, including parties in different states, cross-border performance, foreign capital or international movement of goods or capital.

No automatic statutory joinder

As a practical inference from the statutory texts, neither the Code of Civil Procedure nor the International Arbitration Law contains a complete standalone system regulating joinder and consolidation comparable to detailed modern institutional rules.

The parties’ chosen institutional rules, arbitration agreements and procedural consent therefore play a central role.

This makes clause drafting particularly important. Parties who anticipate connected disputes should select rules expressly addressing multiple contracts, consolidation and multi-party tribunal appointment.

Consent Is the Foundation of Multi-Party Arbitration

A tribunal derives jurisdiction from the arbitration agreement.

Article 412 of the Code of Civil Procedure and Article 4 of the International Arbitration Law define arbitration through the parties’ agreement to refer disputes to arbitrators. The written-form requirement is therefore not a minor procedural formality. It identifies who consented, which disputes were referred and under what contractual framework.

Before adding a party, the following questions should be examined:

1. Did the proposed party sign the contract?
2. Did it sign a separate guarantee or accession document?
3. Does that document contain or incorporate the arbitration clause?
4. Was the contract assigned to or from the proposed party?
5. Is the party a legal successor?
6. Did an authorised agent agree to arbitration on its behalf?
7. Did it later agree in writing to join the proceeding?
8. Does the applicable institutional rule authorise joinder on a recognised basis?

Commercial convenience does not cure the absence of jurisdiction.

A tribunal that decides claims against a non-consenting company risks having the relevant part of its award set aside or refused enforcement.

Non-Signatories and Group Companies

Large transactions often use several companies within the same corporate group.

One company may negotiate the contract, another may sign it, another may issue invoices and a parent company may supervise performance.

A claimant may argue that all group companies should be treated as parties to the arbitration. The proposed respondents may argue that only the signatory company accepted the clause.

The following facts may be relevant:

• Who signed the contract;
• Whether the signatory acted as an agent;
• Whether the parent signed a guarantee;
• Whether an affiliate expressly assumed obligations;
• Whether a contract was assigned;
• Whether the arbitration clause was incorporated into another agreement;
• Whether the additional company later accepted arbitration.

The existence of common shareholders, directors, branding or management is not necessarily enough.

Parties seeking parent-company liability should obtain a written guarantee containing a compatible arbitration clause rather than relying on an uncertain attempt to extend the principal contract’s clause after a dispute arises.

Multiple Contracts under the ISTAC Rules

Article 10 of the ISTAC Arbitration Rules expressly permits claims and relief arising out of or connected with more than one contract to be resolved in a single arbitration where:

1. All relevant contracts refer disputes to arbitration under the ISTAC Rules; and
2. The arbitration agreements are compatible with one another.

This mechanism can be used where a claimant has already identified several connected contracts before commencing arbitration.

For example, a claimant may file one request based on:

• A main supply agreement;
• A pricing protocol;
• A guarantee;
• A settlement agreement.

Article 10 does not eliminate the need to prove jurisdiction under each arbitration agreement. It creates a procedural route for presenting compatible claims together.

What Does Compatibility Mean?

The ISTAC Rules do not provide an exhaustive definition of compatibility. The issue must therefore be evaluated according to the relevant clauses and circumstances.

Factors may include whether the clauses use the same:

• Arbitration institution;
• Seat;
• Language;
• Number of arbitrators;
• Appointment mechanism;
• Procedural rules;
• Scope of disputes;
• Expedited or ordinary procedure.

Not every difference necessarily makes the clauses incompatible.

For example, one contract may be governed by Turkish law and another by English law while both clauses provide for ISTAC arbitration seated in Istanbul before three arbitrators. Different substantive governing laws may increase complexity but do not necessarily make the arbitration mechanisms contradictory.

By contrast, the following clauses may be difficult to combine:

• One contract requires ISTAC arbitration and another ICC arbitration;
• One requires a sole arbitrator and another requires three;
• One selects Istanbul and another selects Paris;
• One requires Turkish and another requires English;
• One excludes consolidation expressly;
• One reserves the dispute exclusively for Turkish courts.

The safest approach is to use identical or expressly coordinated clauses across all project documents.

Consolidation under Article 11 of the ISTAC Rules

Article 11 authorises the ISTAC Board, upon a party’s request, to consolidate two or more pending ISTAC arbitrations when the rule’s conditions are satisfied.

The conditions differ depending on whether the parties in the arbitrations are the same.

Arbitrations involving different parties

Where the parties to the pending arbitrations are different, consolidation requires the agreement of all parties.

For example:

• Arbitration A is between the employer and contractor;
• Arbitration B is between the contractor and subcontractor.

Because the party groups are not identical, all three companies would need to agree to consolidation under this branch of Article 11.

A commercial connection between the contracts is not enough by itself.

Arbitrations involving the same parties

Where the parties are the same, consolidation may be available where:

• The parties agree;
• All claims are based on the same arbitration agreement; or
• The claims arise under more than one arbitration agreement, the disputes relate to the same legal relationship and the arbitration agreements are compatible.

This gives the Board greater flexibility where the same claimant and respondent commenced separate proceedings under connected contracts.

Factors considered by the Board

The Board considers relevant circumstances, including:

• Whether arbitrators have already been designated;
• Whether the designated arbitrators are the same;
• The procedural stage reached by each arbitration;
• The likely effect on fairness and efficiency.

Where the respondent’s co-arbitrator has not yet been designated at the time of the consolidation request, that appointment is suspended until the Board decides the request. If consolidation is granted, the cases are normally consolidated into the arbitration commenced first unless all parties agree otherwise.

Why Timing Matters

A consolidation request should be made as early as possible.

Early consolidation may allow:

• One tribunal to be constituted;
• A single procedural timetable;
• Coordinated document production;
• Joint technical experts;
• One evidentiary hearing;
• One final award.

Late consolidation may cause greater difficulty where:

• Different tribunals have already been constituted;
• The arbitrators are not the same;
• One proceeding is close to a final award;
• Different procedural orders have been issued;
• Evidence has been presented under inconsistent schedules;
• One party would lose a procedural opportunity.

The appointment of arbitrators is particularly important because the parties’ right to participate equally in tribunal formation must be protected.

Joinder under the ISTAC Framework

The published ISTAC Arbitration Rules contain express provisions on:

• Claims under multiple contracts;
• Consolidation of pending arbitrations;
• Appointment of arbitrators in multi-party cases.

They do not contain a separate, broadly framed joinder article equivalent to the standalone joinder provisions found in some newer institutional rule sets.

As a procedural and drafting consequence, a party seeking to add a new participant to an existing ISTAC arbitration should identify a clear jurisdictional basis.

Possible approaches include:

• Obtaining written consent from all relevant parties;
• Concluding a written submission agreement;
• Commencing a separate ISTAC arbitration against the additional party and requesting consolidation where Article 11 permits;
• Establishing assignment, succession or another recognised basis showing that the additional party is bound by the clause.

Attempting to add a non-signatory without a clear legal basis may jeopardise the efficiency and enforceability that joinder is intended to achieve.

Tribunal Appointment in Multi-Party Cases

Tribunal appointment can be one of the most difficult issues in multi-party arbitration.

In a traditional two-party case with three arbitrators:

• The claimant chooses one arbitrator;
• The respondent chooses one arbitrator;
• The two co-arbitrators or institution select the chair.

In a case with three claimants and four respondents, it would undermine equality if every individual party could appoint its own arbitrator.

Article 14 of the ISTAC Rules addresses this issue. Where there are multiple claimants or multiple respondents, the parties on each side must jointly agree on the nomination of their side’s arbitrator. If they cannot agree, the ISTAC Board appoints the arbitrator on behalf of the side that failed to make a joint nomination.

This approach preserves the tribunal’s ordinary size while avoiding appointment inequality.

Parties on the Same Side May Have Conflicting Interests

Procedural alignment does not always mean commercial alignment.

Several respondents may deny the claimant’s case while also blaming one another.

For example:

• A contractor alleges that delay was caused by the designer;
• The designer alleges that the contractor ignored the design;
• The guarantor denies liability even if the contractor is liable.

Requiring these respondents to nominate one arbitrator jointly may be difficult.

The arbitration clause may address this problem by giving the institution authority to appoint all tribunal members where multi-party appointment fails. Parties should also consider whether separate proceedings followed by consolidation would protect appointment rights more effectively.

Equality and the Right to Be Heard

Both Turkish domestic and international arbitration legislation require procedural equality.

Article 423 of the Code of Civil Procedure provides that parties have equal rights and powers in arbitration and must be given the opportunity to exercise their right to be heard. Article 424 allows the parties to determine the procedural rules, including by referring to institutional rules, subject to mandatory provisions.

The International Arbitration Law similarly requires equal rights and an opportunity to present claims and defences.

In multi-party proceedings, this means that every party should receive:

• Notice of the claims;
• Access to relevant submissions and evidence;
• An opportunity to object to jurisdiction;
• A reasonable opportunity to present its case;
• Equal treatment in tribunal constitution;
• An opportunity to comment on consolidation;
• An opportunity to challenge arbitrators where permitted.

Efficiency does not justify preventing one party from addressing evidence or arguments that may determine its liability.

Jurisdictional Objections

A party may object that:

• It never agreed to arbitration;
• Its agreement covers only one contract;
• The arbitration clauses are incompatible;
• The claim falls outside the clause;
• The consolidation conditions were not satisfied;
• The tribunal was improperly constituted;
• The proposed cross-claim is not arbitrable.

Under the competence-competence principle, the tribunal may determine its own jurisdiction, including objections concerning the existence, validity and scope of the arbitration agreement. The ISTAC Rules recognise this authority and the separability of the arbitration clause from the main contract.

Jurisdiction should be analysed separately for:

• Each party;
• Each contract;
• Each claim;
• Each counterclaim;
• Each requested remedy.

A tribunal may have jurisdiction over the payment claim against the contractor but not over a separate claim against the contractor’s parent company.

Cross-Claims between Respondents

Multi-party disputes may include claims between parties that are formally on the same side.

For example, a project owner sues the contractor and designer. The contractor may seek contribution or indemnification from the designer.

Whether the tribunal can determine that cross-claim depends on:

• Whether the contractor and designer are bound by an arbitration agreement covering the claim;
• Whether the institutional rules permit the claim procedurally;
• Whether the claim falls within the scope of the pending arbitration;
• Whether the other parties receive a proper opportunity to respond.

The claimant’s arbitration agreement with each respondent does not automatically create an arbitration agreement between the respondents.

Project documents should therefore include reciprocal arbitration clauses where contribution or indemnity claims are foreseeable.

Assignment, Transfer and Succession

A contract containing an arbitration clause may later be assigned.

This commonly occurs through:

• Receivables assignments;
• Business transfers;
• Mergers;
• Financing security;
• Insurance subrogation;
• Corporate restructurings.

The transferee’s rights and obligations concerning arbitration depend on the legal nature of the transaction and applicable law.

The parties should document:

• Whether only the receivable or the entire contract is transferred;
• Whether obligations are assumed;
• Whether counterparty consent is required;
• Whether the arbitration clause transfers;
• Whether the assignee signs an accession agreement;
• Whether the assignor remains liable.

An express accession to the arbitration clause reduces later jurisdictional disputes.

Guarantees and Parent-Company Undertakings

A guarantee should contain its own dispute resolution provision.

A common drafting problem is:

• Main contract: ISTAC arbitration;
• Parent guarantee: silent;
• Security agreement: Turkish courts.

The beneficiary may later attempt to bring all claims in one arbitration. The guarantor may object that it never accepted the main contract’s arbitration clause.

The guarantee should state expressly that:

• Disputes under the guarantee are subject to the same arbitration rules;
• The seat, language and tribunal size are identical;
• Consolidation with the main contract arbitration is permitted;
• The guarantor consents to joint tribunal appointment.

Parallel Proceedings and Conflicting Awards

Where joinder or consolidation is unavailable, related disputes may proceed separately.

Parallel proceedings create several risks.

Inconsistent factual findings

One tribunal may find that equipment was defective. Another may find that the operator’s misuse caused the failure.

Double recovery

A claimant may seek the same loss from more than one respondent.

Contribution problems

One party may be held liable before it can recover from the responsible subcontractor.

Different procedural schedules

One case may conclude before evidence from another becomes available.

Increased costs

The same witnesses and experts may appear in several proceedings.

Possible solutions include:

• Coordinated timetables;
• Appointment of the same tribunal;
• Agreed sharing of evidence;
• Stays;
• Partial awards;
• Contractual contribution mechanisms;
• Settlement of one part of the dispute.

These solutions normally require party cooperation and careful protection of confidentiality.

Confidentiality in Related Proceedings

ISTAC Rule 21 states that arbitration proceedings are confidential unless the parties agree otherwise and permits the tribunal to issue confidentiality orders and protect trade secrets and confidential information.

However, separate arbitrations may have different parties. A document produced in one case cannot automatically be used in another.

The parties should address:

• Cross-use of evidence;
• Common confidentiality clubs;
• Expert access;
• Disclosure to insurers or lenders;
• Treatment of settlement communications;
• Use of awards in contribution proceedings.

A coordinated confidentiality protocol may allow efficiency without disclosing commercially sensitive information to unrelated parties.

Interim Measures in Multi-Party Disputes

Urgent relief may be required before joinder or consolidation is resolved.

A party may seek to:

• Prevent transfer of project shares;
• Preserve common evidence;
• Stop disposal of disputed goods;
• Secure receivables;
• Preserve electronic records;
• Prevent a guarantee payment;
• Maintain access to a project site.

Article 414 of the Code of Civil Procedure permits qualifying interim measures and evidence preservation during domestic arbitration and provides for court assistance in specified circumstances.

In a multi-party case, the requested measure must be directed carefully.

An arbitral tribunal’s authority normally extends only to parties bound by the arbitration agreement. A measure requiring action by a bank, registry, subcontractor or public authority may require judicial assistance.

Costs and Procedural Economy

Consolidation may reduce:

• Registration costs;
• Arbitrator fees;
• Repeated expert work;
• Duplicate witness preparation;
• Hearing expenses.

However, a consolidated case is not always cheaper.

The arbitration may become more complex because:

• Several legal teams participate;
• More jurisdictional objections arise;
• Different governing laws apply;
• The document record becomes larger;
• Cross-claims require additional pleadings;
• Hearing time increases.

The tribunal should use active case management.

Possible procedural tools include:

• Separate jurisdictional phases;
• Common factual chronologies;
• Joint expert reports;
• Issue-based document production;
• Bifurcation;
• Partial awards;
• Separate cost accounts;
• Defined page and hearing limits.

Drafting Multi-Party Arbitration Clauses

The best time to address multi-party risk is before the contracts are signed.

All project documents should use compatible provisions concerning:

• Arbitration institution;
• Seat;
• Language;
• Number of arbitrators;
• Appointment method;
• Governing law;
• Confidentiality;
• Emergency relief;
• Joinder;
• Consolidation.

An illustrative coordinated clause may provide:

Any dispute, controversy or claim arising out of or in connection with this Agreement, including its formation, validity, interpretation, performance, breach or termination, shall be finally resolved under the Istanbul Arbitration Centre Arbitration Rules.

The seat of arbitration shall be Istanbul, Türkiye. The tribunal shall consist of three arbitrators. The language of arbitration shall be English.

The parties agree that claims arising out of or in connection with this Agreement and any Related Agreement may be brought in a single arbitration where the applicable arbitration agreements are compatible. The parties further agree, to the fullest extent permitted by the ISTAC Arbitration Rules, to the consolidation of related arbitrations and to the participation of parties to the Related Agreements.

The contract should define “Related Agreement” specifically.

A broad reference to every agreement connected with the project may create uncertainty and may purport to bind parties that never signed the clause.

Master Arbitration Agreements

For particularly complex transactions, the parties may sign a master dispute resolution agreement.

The agreement may be signed by:

• Project company;
• Shareholders;
• Main contractor;
• Guarantors;
• Key suppliers;
• Operator.

It may establish:

• One institution;
• One seat;
• One language;
• A common tribunal appointment method;
• Express consent to joinder and consolidation;
• Cross-claim jurisdiction;
• Evidence-sharing rules;
• Confidentiality.

This may be more effective than attempting to coordinate numerous inconsistent clauses after a dispute arises.

Annulment Risks in Turkey-Seated Arbitration

Multi-party awards may be challenged where the procedure failed to respect jurisdictional or procedural safeguards.

Under Article 439 of the Code of Civil Procedure, a domestic award may be set aside on limited grounds including:

• Invalid arbitration agreement;
• Failure to follow the agreed tribunal appointment procedure;
• Unlawful jurisdictional decision;
• Decision beyond the arbitration agreement;
• Material failure to follow the agreed procedure;
• Violation of equality or the right to be heard;
• Non-arbitrability;
• Public policy.

Article 15 of the International Arbitration Law contains comparable grounds for qualifying international awards seated in Türkiye, including invalidity, improper tribunal constitution, jurisdictional excess, procedural violation and failure to respect equality.

A consolidation decision is therefore not merely an administrative convenience. The resulting tribunal and proceeding must remain consistent with the parties’ arbitration agreements and procedural rights.

Enforcement of Multi-Party Awards

A multi-party award should identify clearly:

• Every party bound by the award;
• The jurisdictional basis concerning each party;
• Each claim and counterclaim;
• Whether liability is joint, several or joint and several;
• Payment obligations;
• Interest;
• Costs;
• Any declaratory or performance relief.

Ambiguous collective language may create enforcement difficulty.

The New York Convention’s principal objective is to ensure that foreign and non-domestic arbitral awards are recognised and generally capable of enforcement in contracting jurisdictions. Enforcement remains subject to the Convention’s limited refusal framework.

In a multi-party case, particular attention should be paid to objections that:

• The relevant company never consented;
• It was not properly notified;
• It could not present its case;
• The tribunal was constituted contrary to the agreement;
• The award exceeded the submission to arbitration.

A carefully reasoned jurisdiction section can reduce these risks.

Practical Multi-Party Arbitration Checklist

Before commencing a multi-party or multi-contract arbitration, counsel should determine:

1. Which contracts contain arbitration clauses;
2. Which parties signed each clause;
3. Whether any party acceded later;
4. Whether the clauses select the same institution;
5. Whether the seats are compatible;
6. Whether the tribunal sizes match;
7. Whether the languages are compatible;
8. Whether claims arise from the same legal relationship;
9. Whether one arbitration can be commenced under Article 10;
10. Whether separate arbitrations should be consolidated under Article 11;
11. Whether all parties must consent;
12. Whether tribunals have already been constituted;
13. How same-side arbitrator nomination will occur;
14. Whether cross-claims are covered;
15. Whether confidentiality permits evidence sharing;
16. Whether interim measures are required;
17. Whether parallel proceedings should be stayed or coordinated;
18. Whether the award will clearly allocate liability;
19. Where each respondent owns assets;
20. Which enforcement objections may arise.

Frequently Asked Questions

What is multi-party arbitration?

It is arbitration involving more than one claimant, more than one respondent or both.

What is multi-contract arbitration?

It is arbitration in which claims arise from or relate to more than one agreement.

What is the difference between joinder and consolidation?

Joinder adds a new party to an existing arbitration. Consolidation combines two or more pending arbitrations into one proceeding.

Can claims under several contracts be filed in one ISTAC arbitration?

Yes, where all relevant contracts refer to arbitration under the ISTAC Rules and the arbitration agreements are compatible, as required by Article 10.

When can ISTAC arbitrations involving different parties be consolidated?

Where the parties in the arbitrations are different, all parties must agree to consolidation.

Can arbitrations involving the same parties be consolidated without a new agreement?

Potentially. Article 11 permits consolidation where the same parties are involved and the claims rely on the same arbitration agreement or arise from the same legal relationship under compatible arbitration agreements.

Who decides an ISTAC consolidation request?

The request is submitted to the ISTAC Secretariat, which consults the parties and transmits the request to the ISTAC Board for decision.

Which arbitration continues after consolidation?

Unless all parties agree otherwise, the proceedings are consolidated into the arbitration commenced first.

Can an affiliated company be joined merely because it belongs to the same corporate group?

Not automatically. A legal basis establishing consent to arbitration must be identified.

Does a parent guarantee automatically follow the main contract’s arbitration clause?

Not necessarily. The guarantee should contain or expressly incorporate a compatible arbitration clause.

How is an arbitrator selected where there are several claimants or respondents?

Under the ISTAC Rules, multiple claimants and multiple respondents must jointly nominate the arbitrator for their respective side. If they cannot agree, the ISTAC Board makes the appointment for that side.

Can respondents bring claims against one another?

Only where there is a jurisdictional and procedural basis covering those cross-claims. The claimant’s separate agreements with each respondent may not be sufficient.

Can consolidation be requested after arbitrators are appointed?

A request may still be made, but the ISTAC Board considers whether arbitrators have already been designated and whether they are the same. Late consolidation may therefore be more difficult.

Can a multi-party award be annulled?

A Turkey-seated award may be challenged on limited statutory grounds, including invalid arbitration agreement, improper tribunal constitution, jurisdictional excess and violation of equality or the right to be heard.

Can a multi-party foreign award be enforced in Türkiye?

A qualifying foreign award may be recognised and enforced under the New York Convention or applicable Turkish private international law, subject to limited refusal grounds.

Conclusion

Multi-party and multi-contract arbitration in Turkey is increasingly important because modern commercial projects rarely involve only two companies and one agreement.

Construction, energy, finance, M&A, distribution, maritime and technology disputes commonly arise from a network of contracts. Separate proceedings may produce repeated evidence, higher costs and conflicting decisions.

ISTAC provides two particularly important mechanisms.

Article 10 allows claims arising from more than one contract to be resolved in a single arbitration where all contracts refer to ISTAC arbitration and the arbitration agreements are compatible.

Article 11 permits consolidation of pending ISTAC arbitrations under defined conditions. Where the parties differ, all parties must consent. Where the parties are the same, consolidation may also be available based on the same arbitration agreement or connected legal relationships and compatible clauses.

Multi-party efficiency nevertheless remains subject to consent.

A company should not be added merely because it is commercially connected, belongs to the same group or participated in negotiations. The jurisdictional basis must be established for every party and every claim.

Tribunal appointment is equally important. Multiple claimants or respondents must participate equally in the appointment process. Under the ISTAC Rules, parties on each side jointly nominate their arbitrator, and the Board appoints where they cannot agree.

The strongest drafting strategy is to coordinate dispute resolution provisions across all transaction documents.

Project contracts should use the same:

• Institution;
• Seat;
• Language;
• Tribunal size;
• Appointment procedure;
• Joinder and consolidation framework.

Guarantees, direct agreements, shareholder arrangements and ancillary contracts should contain express and compatible clauses.

Once a dispute arises, the parties should evaluate joinder and consolidation immediately. Delay may result in different tribunals, inconsistent procedural schedules and loss of the opportunity to combine cases effectively.

A properly structured multi-party proceeding can provide a complete and commercially coherent resolution. A poorly structured proceeding may create serious jurisdictional, annulment and enforcement risks.

For companies involved in interconnected Turkish and international transactions, specialised arbitration counsel can assist with clause drafting, multi-contract case strategy, consolidation requests, tribunal appointment, jurisdictional objections and enforcement of multi-party awards.