Volatility and Trading Activity Following Changes in the Size of Futures Contracts

This paper examines the relationship between daily price volatility and trading activity one year before and after a change in the size of selected futures contracts. The following three contracts are included in this study: the Stock Price Index traded on the Sydney Futures Exchange (SFE), which had a contract split on October 11, 1993; the FTSE-100 index traded on the London International Financial Futures Exchange (LIFFE), which had a contract split on March 23, 1998; and the 90-Day Bank Acceptance Bill (BAB) traded on the SFE, which had a reverse split on May 1, 1995. We obtain several interesting empirical results. We observe that there is a positive relationship between daily price volatility and the number of trades (trading frequency) before and after a change in the size of the examined futures contracts. We find that the increase (decrease) in total trading frequency has the power to explain the increase (decrease) of daily price volatility after a contract split (reverse split). Most of the average trade size variable has an immaterial impact on price volatility. Decomposing the total trading frequencies into four trade size classes, we find that the trading frequencies for small and large trade size categories are highly significant in explaining changes in daily price volatility after the index futures contracts' splits. These results are consistent with the noise trading hypothesis (Black (1986)) and the hypothesis on less informed trading in index futures markets. For the BAB case, we find that the trading frequencies for small, medium and large sizes impact price volatility before and after the reverse contract split