Turnover externalities with marketplace trading

This article considers equilibrium decentralized trade when there is a marketplace where buyers and sellers meet costlessly. Since buyers have idiosyncratic match payoffs for each seller's good, some buyers, rather than trade with the current stock of sellers, wait for new sellers to enter the marketplace to obtain a good they like. A turnover externality exists where all traders are better off with higher entry rates of new traders. Furthermore, this turnover externality supports multiple Pareto-rankable equilibria. This provides new insights into similar results obtained in the random-matching literature.