The Effect Of Price Limits Changes On Return Volatility: Evidence From The Stock Exchange Of Thailand

Abstract

This paper investigates the effect of price limits changes on stock return behavior on the Stock Exchange of Thailand (SET). We compare the short run behavior of stock return under different regimes of price limits. The comparison is based on structural volatility, as measured by ratio of open-to-open return variance and close-to-close return variance. We also examine the covariance components of the 24-hour return and 12-hour return to detect the relation between limit width and the pattern of overreaction. We analyze the impact of trading volume and market value on structural volatility and overreaction as well. We find that return behavior at the SET is found to be rather consistent with those of other exchanges that employed price limit namely, Tokyo Stock Exchange and Taiwan Stock Exchange. In particular, the changes of price limit at the SET magnify the pattern of return behavior that exists before and after the changes resulting in increases in structural price volatility and overreaction during the narrow limit regime.