Bertrand-Edgeworth duopoly with unit cost asymmetry

Summary This paper characterizes the set of Nash equilibria in a price setting duopoly in which firms have limited capacity, and in which unit costs of production up to capacity may differ. Assuming concave revenue and efficient rationing, we show that the case of different unit costs involves a tractable generalization of the methods used to analyze the case of identical costs. However, the supports of the two firms' equilibrium price distributions need no longer be connected and need not coincide. In addition, the supports of the equilibrium price distributions need no longer be continuous in the underlying parameters of the model.As an application of our characterization, we examine the Kreps-Scheinkman model of capacity choice followed by Bertrand-Edgeworth price competition and show that, unlike in the case of identical costs, Cournot equilibrium capacity levels need not arise as subgame-perfect equilibria. The low-cost firm has greater incentive to price its rival out of the market than exists under Cournot behavior.We are grateful to Joseph Harrington, Marie Thursby, Casper de Vries and, especially, William Novshek for helpful discussions and comments. Thomas Faith and Ioannis Tournas provided valuable research assistance. This paper was presented at the Winter Meetings of the Econometric Society in December 1988, the Midwest Mathematical Economics Conference in April 1989, the Sixteenth Annual Congress of the European Association for Research in Industrial Economics in August 1989, the European Meetings of the Econometric Society in September 1989, and in seminars at the Ecole Nationale des Ponts et Chaussées, Erasmus University Rotterdam, Indiana University, INSEAD, Texas A&M University, Tilburg University, the University of Bonn and the University of Florida. Deneckere acknowledges financial support through National Science Foundation Grant SES-8619012 and the Kellogg Graduate School of Management's Beatrice/Esmark Research Chair. Kovenock acknowledges financial support through Erasmus University Rotterdam, the Purdue Research Foundation, the Ford Motor Company Fund, and an Ameritech Foundation Summer Faculty Research Grant.