Bargaining in Collusive Markets

In this paper we investigate collusion in an infinitely repeated Bertrand duopoly where firms have different discount factors. In order to study how a collusive agreement is reached we model the equilibrium selection as an alternating-offer bargaining game. The selected equilibrium has several appealing features: First, it is efficient in the sense that it entails immediate agreement on the monopoly price. Second, the equilibrium shows how discount factors affect equilibrium market shares. A comparative statics analysis on equilibrium market shares reveals that changes in discount factors may have ambiguous effects on market shares.