Asymmetric information in commodity futures markets: Theory and empirical evidence

This article examines the theoretical and empirical implications of asymmetric information in commodity futures markets. In particular, it formulates and tests a theoretical model that recognizes two distinct categories of traders: hedgers, who participate in both spot and futures markets, and speculators, who participate only in the futures market. Speculators are assumed to possess differential information about the realized values of selected random variables. Multiperiod futures market equilibria are derived under competitive conditions, and the ability of futures markets to forecast changes in equilibrium spot market prices are examined. The key variable is shown to be the randomness and informational asymmetry in the aggregate supply by participating hedgers in the spot market, whose absence turns out to be the major determinant of the revelation of informational asymmetry. Moreover, under the assumption of independence of error forecasts for prices and spot market supplies, it is shown that futures market equilibrium ends up with linear expressions for prices and futures contract volumes. These linear expressions are then used to develop empirically testable models. The main empirical implications in these models revolve around the role of the basis as a predictor of future spot price changes. The paper provides an empirical investigation of these implications, using three commodities traded on the Winnipeg Commodity Exchange (WCE). © 1998 John Wiley & Sons, Inc. Jrl Fut Mark 18:803–825, 1998