Oligopoly, Endogenous Monopolist and Product Quality

This paper investigates an oligopolistic market with vertical product differentiation, where qualities are represented by a uni-dimensional interval. We examine the Nash equilibrium in the oligopoly game with a finite number of consumers, where each firm uses its technology and can offer a range of quality-price pairs, and firms' profits are determined by the consumers' selection choice. We show that under the standard conditions on consumers' preferences at most one firm with a positive profit can be active in equilibrium. In contrast, we present an example of a duopoly game with a continuum of consumers, in which both firms yield positive profits in an equilibrium. Finally, we analyze in the linear case the question of existence.