本篇論文研究注重在兩個部分，第一，家族企業和放空行為之間的關係，第二，外資與放空行為之間的關係。家族企業中的家族成員具有資訊優勢，能夠利用反向訊息賣空以賺取短期報酬，但長期而言卻可能失去公司治理權。因此，家族企業的存在會阻礙或促進知情放空交易是本研究的重點。另外，外資是能夠擁有資訊優勢的投資機構，對公司的看法會影響其他投資人的交易行為，進而產生異常放空。
　　本論文以2017年到2018年的台灣上市公司共5,330筆資料為樣本，原因在於台灣股票市場存在資訊不對稱，消息掌握在大型投資者中，知情賣空行為容易發生。實證結果顯示，家族企業在面對負向未預期盈餘時，並不會進行提前的放空，與非家族企業無顯著差異。而外資持有股權的公司在面對負向未預期盈餘時，市場上會出現異常放空，與外資無持有股權的公司有顯著差異。

This paper focuses on two parts. First, I investigate the potential relationship between family firms and short sales. Second, I study the possible relationship between foreign investors and short sales. While family members in a family business can use adverse information to reap short-term gains via short sales, they are likely to lose long-term control benefits through short sales. Therefore, the issue of whether family members of family-controlled firms hinder or facilitate informed short-selling transactions is the focus of my study. I secondly examine whether abnormal short sales significantly increase with foreign ownership because foreign investors often gain an information advantage over domestic investors.
　　In a sample of Taiwan’s publicly traded firms from 2017 to 2018, I find that family firms do not engage in more advance short sales than non-family firms when negative earning shocks occur. However, companies with more foreign ownership experience more abnormal short sales than companies with less foreign ownership when negative earning shocks arise. My results overall show that short-selling activities are not significantly related to family -controlled firms but are associated with foreign ownership.

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