本研究主要目的在探討，平盤以下不能放空政策對於我國股市的影響。由於平盤 以下不能放空政策主要在限制，空頭時間的融券放空，雖其可能可以減少作空的 力度，可是，相對而言，由於空頭交易日不能融券作空，代表平盤以下的個股不 得進行融券當沖，因而對交易量產生相當程度的負面衝擊。其次，平盤以下不 能放空會造成空頭恆空，多頭恆多的現象，也就是資金會更集中於市場注目的產 業或類股。研究結果發現整體而言平盤限制使得成交量、週轉率、標準化的成交 量皆有顯著降低。 / The purpose of this research is to discuss the effects of short sales restrictions below the last closing price on Taiwan stock market. The main restriction of the policy is the limitation of short sale in the declining market. First, the policy could lighten the force of the short sale; however, on the other hand it means that some stocks could not day trade when their price of the short sale is below the last closing price. Therefore, the volumes of the trade would have the negative effects due to the policy. Second, the policy could result in the down market remaining declining or the up market remaining increasing. In other word, it makes the capital accumulate in the certain focusing industries or stocks. The empirical results show that the volumes of the trade, the turnover and the standardized trading volume decrease after the short-sales restrictions below the last closing price takes effect.