Short sale and stock returns: Evidence from the Taiwan Stock Exchange

Using short sale data of the Taiwan Stock Exchange from January 1991 to September 2004, we examine the informational role played by short interest in stock price formation. Consistent with previous findings based on the US and Australian stock markets, our results show that heavily shorted stocks generate significant and negative risk-adjusted abnormal returns. Moreover, the negative abnormal returns decrease in magnitude and also become statistically insignificant as the holding period extends from 1 month to 1 year. In addition, we test the effect on stock price overvaluation of the interaction of a short sale constraint and a dispersion of opinion. When using turnover ratio as a proxy for a dispersion of opinion, we find that even when the holding period is 6 months, the overvaluation is still significant. Moreover, when a high degree of a dispersion of opinion is captured by a high relative short interest and a high relative margin trade level, the overvaluation remains statistically significant even for a 1-year holding period.