TESTS OF UNBIASEDNESS IN THE FOREIGN-EXCHANGE FUTURES MARKETS - AN EXAMINATION OF PRICE LIMITS AND CONDITIONAL HETEROSCEDASTICITY

Daily price limits, an institutional feature of futures markets, truncate the distribution of price changes and dampen the variance. Previous tests of the unbiasedness hypothesis using daily foreign exchange futures prices have accounted for the observed conditional heteroscedasticity in the data but have neglected to adequately incorporate the additional effects of daily price limits. This article examines both time variation and truncation of futures price changes. Empirical results suggest that previous rejections of the unbiasedness hypothesis in the foreign exchange futures market are not substantively altered by inclusion of price limits but may be attributed to potentially biased testing procedures.