Small trades and volatility increases after stock splits

In this paper, we examine the trading activity and return volatility pattern before and after splits. Unlike previous studies, we employ high-frequency transaction data and more powerful asymptotical tests on the impact of split on volatility. Furthermore, we examine the relationship between volatility and volume using different volatility measures and controlling for the effects of autocorrelation and trading costs. We find that small trades increase significantly after stock splits and the increase in return volatility is strongly related to the increase in small trades after stock splits. The results support our contention that the post-split volatility increase is driven primarily by the trading activity of smaller noise investors. Test results are robust to different measures of trading activity and return volatility.