This article considers vertical relations between an upstream manufacturer and a downstream retailer that can independently obtain a low‐quality, discount substitute. The analysis reveals that under full information, the retailer offers both varieties if and only if it is optimal to do so under vertical integration. However, when the retailer is privately informed about demand, it offers both varieties even if under vertical integration it is profitable to offer only the manufacturer's product. If the manufacturer can impose exclusive dealing, then under asymmetric information it will do so and foreclose the low‐quality substitute even if under vertical integration it is profitable to offer both varieties.

In the context of platform competition in a two-sided market, we study how exante uncertainty and ex-post asymmetric information concerning the value of a new technology affects the strategies of the platforms and the market outcome. We find that the incumbent dominates the market by setting the welfare-maximizing quantity when the difference in the degree of asymmetric information between buyers and sellers is significant. However, if this difference is below a certain threshold, then even the incumbent platform will distort its quantity downward. Since a monopoly incumbent would set the welfare-maximizing quantity, this result indicates that platform competition may lead to a market failure: Competition results in a lower quantity and lower welfare than a monopoly. We consider two applications of the model. First, we consider multi-homing. We find that multi-homing solves the market failure resulting from asymmetric information. However, if platforms can impose exclusive dealing, then they will do so, which result in market inefficiency. Second, the model provides a new argument for why it is usually entrants, not incumbents, that bring major technological innovations to the market.

This paper considers platform competition in a two

We consider dynamic competition among platforms in a market with network externalities. A platform that dominated the market in the previous period becomes “focal” in the current period, in that agents play the equilibrium in which they join the focal platform whenever such equilibrium exists. Yet when faced with higher‐quality competition, can a low‐quality platform remain focal? In the finite‐horizon case, the unique equilibrium is efficient for “patient” platforms; with an infinite time horizon, however, there are multiple equilibria where either the low‐ or high‐quality platform dominates. If qualities are stochastic, the platform with a better average quality wins with a higher probability, even when its realized quality is lower, and this probability increases as platforms become more patient. Hence, social welfare may decline as platforms become more forward looking.

This paper considers a signaling game between two competing firms and consumers. The firms have common private information concerning their qualities, and some of the consumers are informed about the firms' qualities. Firms use prices and uninformative advertising as signals of quality. The model reveals that in the separating equilibrium, prices are first climbing and then declining with the proportion of informed consumers, while the expenditure on uninformative advertising is declining. Firms' profits are highest when the proportion of informed consumers is at an intermediate level. Pooling equilibria exist if the proportion of informed consumers is below a certain threshold.