Over the last ten years, implicit consent has become one of the major points of contention in the debate about the propriety of class, mass and collective arbitration. The notion of implicit consent is critical to the development of large-scale arbitral proceedings because it allows multiple disputes to be heard at a single time, in a single forum, even if the relevant arbitration agreements are silent regarding the possibility of joint action by the claimants. The issue arises in the context of both international commercial arbitration and investment arbitration.

The divisive nature of the debate suggests that the controversy about implicit consent will continue so long as the discussion continues to be framed in its present terms. However, it may be possible to advance the conversation by expanding the nature of the analysis. Rather than focusing on implicit consent as a matter of treaty or contract interpretation, it might be beneficial to consider implicit consent from a systemic rather than individual perspective. This chapter therefore applies a dispute system design (DSD) analysis to the question of implicit consent. In particular, this discussion considers whether and to what extent the concept of ""regulatory litigation"" (defined herein as including both judicial and arbitral procedures) can be used to justify use of implicit consent as a means of addressing unanticipated risk, including unanticipated procedural risk.

The discussion proceeds as follows. First, Section II considers how regulatory litigation operates and why an analytical framework based on unanticipated risk might be necessary or useful in the context of large-scale arbitration. Section III then describes what constitutes unanticipated risk in disputes involving class, mass and collective injuries and how those issues affect dispute system design in international commercial and investment settings. Section IV addresses some of the criticisms of implicit consent and regulatory litigation by considering the nature of class, mass and collective claims, while Section V considers how implicit consent and regulatory litigation operate to overcome some of the special problems associated with transnational regulatory disputes. Section VI concludes the chapter with a number of forward-looking observations.