On Interdependent Supergames: Multimarket Contact, Concavity, and Collusion

Following Bernheim and Whinston (1990), this paper addresses the effects of multimarket contact on firms’ ability to collude. Real world imperfections tend to make firms’ objective function strictly concave and market supergames “interdependent”: firms’ payoffs in each market depend on how they are doing in others. Then, multimarket contact always facilitates collusion. It may even make collusion sustainable in all markets when otherwise it would not be sustainable in any. The effects of conglomeration are discussed. “Multigame contact” is shown to facilitate cooperation in supergames other than oligopolies as long as agents’ objective function is submodular in material payoffs.

Published in Journal of Economic Theory 89/1 (November 1999), pages 127-139

Access to an Essential Facility: Efficient Component Pricing Rule or Unrestricted Private Property Rights

In this paper we compare the access to an essential facility in two different property rights regimes. In one of them, the owner of the facility has a full private property right. In the other, access is regulated according to the efficient component pricing rule. Proponents of the second regime claim that this rule is efficient, for it forecloses the complementary market only to inefficient producers. We prove that the two legal frameworks are equivalent if we do not consider the possibility of the transfer of the property right and that if this is allowed the efficient component pricing rule might exclude efficient suppliers.