A model of market making by firms with heterogeneous consumers, suppliers and price-setting intermediaries is examined. Consumers and suppliers engage in time-consuming search for the best price and discount future returns. There exists a unique symmetric equilibrium pricing strategy. In equilibrium, there are non-degenerate distributions of ask and bid prices that straddle the Walrasian price. As the discount rate goes to zero, the ranges of the bid and ask prices, and the total output approach the Walrasian equilibrium values. As the discount rate becomes large, the ask and bid prices approach the monopoly pricing policies. An increase in the discount rate leads to an increase in the equilibrium number of active firms, profit per firm, the mean spread between ask and bid prices, and the variance of ask and bid prices, while lowering the number of active consumers and suppliers. The model is extended to examine the steady-state market equilibrium with continual entry and exit of consumers and suppliers.

We use data from an agricultural labour market in which workers receive both time- and piece-rate wages and shift frequently among employers and tasks, to assess the roles of comparative advantage, information problems and preferences in determining the allocation of workers. The estimates which impose minimal structure not implied by economic theory are consistent with a one-factor productivity model, and indicate that information asymmetries are present but workers are sorted according to comparative advantage. In particular, the disproportionate presence of female workers in weeding activities is due not to worker or employer preferences but to comparative advantage and statistical discrimination.