While the concept of third-party notices (in German: “Streitverkündung”) is common practice in German state court proceedings, third-party notice provisions have so far not been reflected in institutional arbitration rules. Recognising the practical need to involve third parties in arbitration proceedings, the Deutsche Institution für Schiedsgerichtsbarkeit eV (DIS) has introduced Supplementary Rules for Third-Party Notices 
(DIS-TPNR), which came into effect on 15 March 2024.

This article provides an overview of the background, scope, and key elements of the new rules, along with an assessment of potential practical implications and critiques.

Pursuant to sections 72 et seq of the ZPO, for a third-party notice to be permissible, there must first be a legal relationship between the notifying party and the third party. Secondly, the notifying party must have a potential claim for recourse against the third party arising from the same legal context as the main dispute. Finally, the notifying party must demonstrate legitimate interest in involving the third party in the proceedings, typically to safeguard its rights or obtain indemnification in the event of an unfavourable outcome in the main dispute. Consensus of the third party is not required. While the third party is free to join the proceedings or abstain, in either scenario, the decisive factual and legal findings are binding on the third party in subsequent proceedings with the notifying party.