Serial Collusion By Multi-Product Firms

We provide empirical evidence that many multi-product firms have each participated in several cartels over the past 50 years. Standard analysis of cartel conduct, as well as enforcement policy, is rooted in the presumption that each cartel in which a given firm participates is a singular activity, independent of other cartel conduct by the firm. We argue that this analysis is substantially deficient in many aspects in the face of serial collusion by multi-product firms. We offer policy recommendations to reign in serial collusion, including a mandatory coordinated effects review for any merger involving a serial colluder, regardless of the apparent nature of the merger.