In the Dixit-Stiglitz model of monopolistic competition, entry of firms is socially too small. Other authors have shown that excess entry is also a possibility with other preferences for diversity. We show that the cost structure and workers's rents can also explain excess entry

In a successive vertical oligopoly, a set of sellers produce some input to be transformed into a final product by a set of buyers. On this two-sided market, a firm's profit increases with the number of firms of the other type and decreases with the number of firms of its own type. We examine the...