We investigate intraday data for KOSPI 200 index and KOSPI 200 index futures. Hourly theoretical futures prices are calculated based on cost of carry model. we compare hourly index futures prices with their theoretical prices. Consistent with a large body of previous researches in this area, we find the persistent deviation of futures prices from their theoretical prices. Futures prices are undervalued relative to their theoretical prices. The data indicate that the difference between futures price and its theoretical price exhibits U-shaped pattern over the trading hours. The differences are higher at open and at 15:00 and are lower over intraday trading hours, implying that previous studies using daily closing prices overstate this mispricing.
We also examine the effect of intraday spot return on the behavior of the difference between the hourly futures price and its theoretical price. The finding indicates that the intraday momentum generates U-shaped pattern of this mispricing. This contrasts with Kim and Park (2011)'s finding that the difference also increases as the prior 60 day spot return increases. Our finding invalidates their explanation the activities of arbitrageurs bring monotonic increasing pattern of the magnitude of this mispricing in their daily data.
We propose a new explanation the U shaped patttern of the difference between the futures price and its theoretical price generated by the intraday spot return's moment. We introduce risk-seeking trader in our new explanation. The trader's risk-seeking behavior is based on prospect theory (Kahneman and Tversky (1979)). We argue that the risk-seeking traders cause intraday momentum effect to generate the U-shaped pattern of this mispricing. We add speculator's variables to Kim and Park (2011)'s regression equation and estimate it. The results from the regression analysis lend support to our new explanation as well as theirs, implying that speculators and arbitrageurs are present and active in the spot and futures markets and generate different pattern of the mispricing.
Using neural networks for forecasting volatility of S&P 500 Index futures prices
