Nonparametric Tests of Commodity Futures Market Efficiency

Commodity futures markets carry out two important marketing functions with respect to agricultural products: (1) a price discovery role and (2) a price risk management role. The relative effectiveness with which futures markets fulfill these two roles is dependent on the efficiency of the futures market and its ability to provide unbiased forecasts of subsequent futures prices at contract maturity. Our results indicate that futures price returns for live cattle, hogs, corn, rice and soybean meal violate the standard OLS assumption of normality. However, nonparametric statistics results did not materially conflict with our OLS parametric results. Further modeling indicated live cattle, hogs and soybean meal futures returns are better specified using GARCH type models, which allow for a non-constant error variance over time