Antitrust Impact in Class/Collective Actions


The authors provide an overview of how economic analysis can be used to assess the common impact question in the U.S., Canada, and the U.K.

In regimes that allow it, litigation alleging a violation of competition law can be pursued as a collective or class action. Typically, an early stage in such litigation is determining whether the action will be permitted to be brought as a class action on behalf of a specified class of claimants. For example, to proceed in the U.S. and Canada, plaintiffs must seek a motion for class certification. In the U.K., claimants must seek a collective proceedings order. Though these three regimes differ in how they consider the question of class certification or collective proceeding, one focal area of inquiry is the commonality of antitrust injury or harm among putative class members. This is often referred to as “common impact.”

Economic analysis is generally central to assessing the common impact question. In this chapter, authors Vivek Mani and Darwin Neher offer an overview of how this analysis appears to be perceived in the class action regimes in the U.S., Canada, and the U.K. They outline key differences and similarities in these regimes, which have important implications for what economic analyses may be seen as dispositive.

The common impact question is made complex because putative classes are often defined to encompass class members who are differentially situated. For example, in a price-fixing case, the individual class members may purchase different, heterogeneous products at different times, from different retailers in different locations, and through different channels. Thus, it is not a given that any particular alleged anticompetitive conduct affected each class member in a common way. Economists draw on competition economics and evidence on the determinants of firms’ prices to evaluate whether any common-to-the-class analysis, or methodology, can establish whether the alleged conduct caused harm to class members.

This chapter was originally published in the International Comparative Legal Guide to: Class and Group Actions in November 2020.

The views expressed herein do not necessarily represent the views of Cornerstone Research.

Antitrust Impact in Class/Collective Actions


  • Boston | London

Vivek Mani

Vice President

  • New York

Darwin V. Neher

Senior Vice President