International commercial arbitration is built on consensus ad idem, where only those who agree to arbitrate should be bound. However, modern global commerce often stretches this principle. Transactions today commonly involve multiple entities, such as subsidiaries, parent companies, and subcontractors, within complex corporate and contractual structures. As a result, disputes frequently arise involving parties who never formally signed the arbitration agreement. To address this reality, courts and tribunals have developed doctrines that permit non-signatories to participate in arbitration under certain circumstances.
Approaches to this issue vary across jurisdictions. In France, for example, the Group of Companies doctrine permits arbitration agreements to extend to affiliated companies within the same corporate group, provided the non-signatory was involved in negotiating or performing the contract and shared an intention to be bound. This doctrine acknowledges that in some commercial realities, corporate separateness does not reflect how business is actually conducted.
In the U.S, the doctrine of equitable estoppel has gained traction. It prevents a party from refusing arbitration when its claims rely on a contract that includes an arbitration clause. It also allows non-signatories to compel arbitration when the signatory’s conduct presumes the contract’s validity. Unlike the Group of Companies doctrine, which focuses on implied consent, equitable estoppel emphasizes preventing unfair or inconsistent conduct.
These doctrines were tested in GE Energy v. Outokumpu, where the U.S. Supreme Court considered whether a non-signatory subcontractor could compel arbitration under an agreement governed by the New York Convention. The Court unanimously held that the Convention did not bar the use of domestic doctrines like equitable estoppel. Since GE Energy’s role was closely connected to contract performance, it could invoke arbitration.
In India, the Supreme Court addressed a similar issue in Cox and Kings v SAP India, which concerned whether SAP SE, the German parent of SAP India, could be joined in arbitration proceedings despite not signing the contracts. The Court upheld the Group of Companies doctrine under Indian law but stressed that its application must be rooted in genuine consent inferred from conduct. Joint participation in contract performance, the composite nature of the transaction, and mutual intent were key. Mere corporate affiliation was deemed insufficient.
These cases highlight the varied and evolving approaches to non-signatories in international arbitration. While some jurisdictions embrace flexibility and commercial reality, others remain firmly anchored in formal consent and corporate structure. Hence, whether a non-signatory can be joined in arbitration may ultimately depend not only on the facts but also on the seat of arbitration or the place of enforcement.
