Sandro Shelegia

Is the Competitor of my Competitor also my Competitor

This paper presents several results on multimarket competition. First, whenever a firm faces multimarket competitors that sell goods in markets to which the firm itself has no access, the firm gains a strong incentive to expand production in its own market(s). In the capacity choice model, such a firm builds larger than Cournot capacity and pushes its competitors towards other markets. Consumers always benefit from multimarket competition. In asymmetric market structures, some firms may also benefit from multimarket arrangements, but in symmetric ones, all firms are necessarily harmed by it. Second, the intensification of indirect competition is not necessarily bad for the firm. It may be the case that, the more competitors its competitors have, the higher the firm’s profit. Finally, this model also has a multiproduct interpretation which suggests that a merger of single‐product firms may be beneficial or harmful from a social welfare perspective, depending on whether the new entity will compete with several single‐product firms or another multiproduct one.

Consumer search with observational learning

This paper studies observational learning in a consumer search environment. In our model, consumers observe the purchasing decision of a predecessor before deciding which rm to visit. We show that if consumers emulate their predecessor and initiate their search at the rm she purchased from, a social multiplier of demand induces a lower equilibrium price. Further, as the search cost increases, rms compete ercely to attract consumers and prices converge to the marginal cost. We show that the result can be extended to any number of rms, and the e ect of emulation on prices is stronger as the number of rms increases. We also show that, as consumers observe more previous purchasing decisions, the downward pressure on prices grows to the degree that the pure strategy equilibrium may cease to exist. We then provide a rationale for emulation by introducing positive correlation in preferences across consumers. This correlation gives rise to free-riding which deters search, and as a result puts further downward pressure on prices for high search cost.