This paper develops a game-theoretic model to study how exclusionary contracts affect firms' incentives to invest in innovation. Several symmetric sellers compete to supply an identical product to a set of buyers, and each seller can invest in R&D to develop a higher-quality version of the...

This paper extends the CES model of monopolistic competition to the case where varieties are both horizontally and vertically differentiated. A distinctive feature of our model is the presence of a network externality, which operates through the number of varieties available at each quality...

We study information design in a vertically differentiated market. A third party publicly discloses information about the product qualities of two competing firms. More precise information improves consumer matching but increases perceived differentiation, enabling firms to raise prices....