Since 2007, Swiss caselaw has developed in a satisfactory manner with regard to the enforcement of multi-tiered clauses. Not only has the Swiss Federal Supreme Court clearly established the cumulative requirements that have to be met to enforce the pre-arbitral tier contained in a multi-tiered clause when a party does not comply with it and directly files an arbitration claim, but the Court has also resolved the question of how the arbitral tribunal should sanction such a violation. In contrast, the issue of the nature of multi-tiered clauses has never benefited from the same attention. Yet, this is a fundamental question as it primarily determines whether the Swiss Federal Supreme Court can review arbitral decisions on claims of non-compliance.   The thesis provides a critical assessment of how Swiss caselaw defines the nature of multi-tiered clauses. The author argues that classifying claims of non-compliance as raising a jurisdictional issue is a mistake and leads to an unjustified extension of the scope of judicial review through the application of art. 190(2)(b) PILA.