Durability, Re-trading and Market Performance

Abstract

Key differential structural characteristics of environments studied in previous market experiments have documented large divergences in their observed performance, particularly discrepancies in their convergence to expected equilibrium outcomes. We investigate why this should be so. The type of competitive equilibrium where a market clears at a particular price as initiated by Arrow and Debreu (1954) has long been studied in the laboratory. We refer to these experiments as Supply and Demand (SD) experiments. SD experiments are highly reduced in form: items are not re-tradable, buyers and sellers are specialized in these roles, and no second commodity, cash, is used as a medium of exchange, although cash enters as a numeraire qua reward incentive for subjects. Markets with these features that are repeated over time converge rapidly to the predicted equilibrium under a regime of strict private dispersed information on individual values that define the equilibrium predictions. In contrast, consider asset markets, in which shares can be freely re-traded against cash within and across periods, shares have well-defined common values based on common public information on expected cash “dividend” yields, and individuals are not specialized as buyers or sellers. These markets produce price bubbles that converge only with experience across repeat sessions. The prospect of re-trade, and perhaps the lack of buyer/seller specialization, results in market behavior that contrasts sharply with the perishable goods that characterize the SD experiments. Building on this background analysis we report new experiments that combine features of both environments and initiate an investigation of how commodity durability that constrains re-trading characteristics affect the observed variation in market performance.