The impact of equity index futures trading on the underlying index volatility: evidence for the ISE-30 stock index futures contracts

Abstract

The issue that futures-trading activity may result in excessive equity volatility has attracted much attention, both academic and regulatory. Many academicians have claimed that the introduction of the futures contracts will lead to an increase in the spot market volatility and destabilize the equity prices. This has also been an important concern for regulators. Many others have argued the contrary and claimed that futures trading will have stabilizing effects on spot prices. There is no theoretical answer that will resolve this debate; proper empirical investigation will give insights on this effect. Many previous empirical studies deal with the developed markets, especially with the US. The number of studies employing emerging market data is quite limited and there are only a handful of studies dealing with the Turkish market. In this study we examine the effect of futures trading on index volatility using the data from an important emerging market: Turkey. Using the Istanbul Stock Exchange 30 (ISE 30) Index data between February 2005 and April 2015, we test the hypothesis that the variance of daily returns in the futures expiration period (9 days before the expiration of the futures contract) is greater than the variance of index returns in the pre-expiration period (10-50 days prior to futures expiration date). The results of the study show that expiration period variance is not greater than pre-expiration variance.