Free Entry, Market Diffusion, and Social Inefficiency with Endogenously Growing Demand

This paper analyzes market diffusion in the presence of oligopolistic interaction among firms. Market demand is positively related to past market size because of consumer learning, networks, and bandwagon effects. Firms enter the market freely in each period with fixed costs and compete in quantities. We demonstrate that the nature of the ineffciency under free entry can change as the market grows, and more importantly, that S-shaped diffusion can be a signal that the number of firms under free entry is initially insuffcient, but eventually excessive.