Two types of agents interact on a pre-existing free platform. Agents value positively the presence of agents of the other type but may value negatively the presence of agents of their own type. We ask whether a new platform can find fees and subsidies so as to divert agents from the existing...

In many markets, user benefits depend on participation and usage decisions of other users giving rise to network effects. Intermediaries manage these network effects and thus act as platforms that bring users together. This paper reviews key findings from the literature on network effects and...

In the spirit of Arrow (1962), we examine, in an oligopoly model with horizontally differentiated products, how much a firm is willing to pay or a process innovation that it would be the only one to use. We show that different measures of competition (number of firms, degree of product...

We consider the effects of taxes for competing two-sided platforms. We first detail how a platform passes a tax increase on its prices. Adding price competition, we study next how the tax affects profits. Because of the strategic implications of the cross-side external effects, the tax increase...

The effects of (private, small-scale) piracy on the pricing behavior of producers of information goods are studied within a unified model of vertical differentiation. Although information goods are assumed to be perfectly differentiated, demands are interdependent because the copying technology...

In many markets, user benefits depend on participation and usage decisions of other users giving rise to network effects. Intermediaries manage these network effects and thus act as platforms that bring users together. This paper reviews key findings from the literature on network effects and...

R&D cooperation is reconsidered in situations where firms direct R&D activities towards a new product that cannibalizes the firms' existing products. For soft cannibalization, the welfare-maximizing arrangement between firms involves, for low R&D costs, the formation of a separate entity that...

This paper investigates the relation between asymmetries in the distribution of shares in joint ventures and asymmetries between the parent companies. When the joint venture and the parent companies are controlled by separate entities, we provide a simple formula to compute the optimal ownership...

This is a successive oligopoly model with two brands. Each downstream firm chooses one brand to sell on a final market. The upstream firms specialize in the production of one input specifically designed for the production of one brand, but they also produce the input for the other brand at an...

The effects of (private, small-scale) copying on the pricing behavior of producers of information goods are studied within a unified model of vertical di¤erentiation. Although information goods are assumed to be perfectly horizontally differentiated, demands are interdependent because the...