Third-degree price discrimination with interdependent demands

This paper analyzes the price, output, and welfare effects of third-degree price discrimination for a monopolist who sells in two interdependent markets. The case where the two goods sold by the monopolist are complements is analyzed as well as the more typical case where the two goods are substitutes. The economic effects of price discrimination are shown to depend on the type and strength of demand interdependence, the curvature of the demands and the slope of marginal cost. The circumstances under which price discrimination causes both market prices to either rise or fall are also analyzed.