The Optimal Prudential Deterrence of Price Fixing Agreements

We analyse the optimal antitrust enforcement against collusion under asymmetric information with a continuum of types. We focus on prudential deterrence, by imposing that expected fines cannot induce losses even off the equilibrium path. Due to incentive compatibility, efficient cartels enjoy positive rents even when prosecution is costless, created through reduced fines and price cost margins. In equilibrium this distortion is lower for more efficient types, while full collusion can be tolerated for high cost cartels. Moreover, regulation with positive transfers is better than antitrust enforcement, which however allows to implement more efficient outcomes than price caps.