In this project we aim to investigate the impact of short-sale constraints on trading behavior of different categories of investor, and thus the impact on volatility. In literature, the impact of short-sales constraints on stock return volatility is still inconclusive. However, not short-sale constraints itself affect the volatility, but by the impact on trading behavior of different categories of investor. The trading behavior of informed and uninformed traders also causes different effects on volatility. Therefore, we study trading behavior around the short-sale constraints and its impact on volatility. Our finding in this project contributes to the regulators in setting a more effective mechanism to stabilize market. 本研究探討放空限制如何影響不同類別投資人的交易行為，進而對波動度造成影響。過去相關研究中，對放空限制是會增加波動度抑或是減少波動度，並未得到一致的結論。然而並非放空限制本身直接影響波動度，而是放空限制影響投資人的交易行為，投資人交易行為的改變再進而影響波動度，且知訊者與非知訊者的交易行為，對波動度也會造成不同的影響。因此本研究延伸過去放空限制與波動度的相關研究，並由投資人交易行為切入，欲深入探討放空限制是否藉由影響投資人交易行為，進而對波動度造成影響。
