A Threshold Error Correction Model for Intraday Futures and Index Returns

Index-futures arbitrageurs enter into the market only if the deviation from the arbitrage relation is large enough to compensate for transaction costs and associated interest-rate and dividend risks. Using a threshold autoregression model for the mispricing error, we estimate the band around the theoretical futures prices within which arbitrage is not profitable for most arbitrageurs. Combining these thresholds with an error correction model, we can make a distinction between the effects of arbitrageurs and infrequent trading on index and futures returns. The impact of the mispricing error on the returns is increasing with the magnitude of the mispricing error, and the effect of futures returns on index returns is significantly larger when the basis is negative