本研究在探討家族、非家族控制企業與私有資訊交易之關係，私有資訊交易是以當未預期盈餘為負時，在每季盈餘宣告前之異常融券放空為判斷依據。我們希望了解家族控制企業相對於非家族控制企業是否存在較多之私有資訊交易。實證結果指出當未預期盈餘為負時，在每季盈餘宣告前，家族控制企業相較於非家族控制企業確實存在較多異常融券放空之現象。另外，我們從實證結果亦發現當未預期盈餘為負時，則家族成員涉入經營程度愈高、家族盈餘分配權愈低以及股份盈餘偏離程度愈高之公司，在每季盈餘宣告前，其融券放空之行為相對於其他企業會比較多，由此推論出家族控制特性與所有權結構和隱含資訊之融券放空行為有關。此外，研究結果亦指出巨量融券放空可以用來預測股票未來之異常報酬，但家族控制企業之巨量融券放空相對於非家族控制企業並沒有提供較多有用資訊來預測股票未來之超額報酬。 / We investigate the relation between the information content of short sales and organization structure. We want to know that informed trading occurs more readily in family-controlled firms than in nonfamily firms. Our analysis indicates that family-controlled firms experience substantially greater abnormal short sales prior to negative earnings shocks than nonfamily firms. The analysis also indicates that family-controlled firms sustain marginally less abnormal short sales prior to positive earnings surprises than nonfamily firms. Supplementary testing indicates that characteristics of family control and ownership intensify informed short selling. Further analysis suggests that high short-selling tend to be informative in predicting future returns. However, we find that high short-selling in family-controlled firms do not contains more useful information in forecasting stock returns than nonfamily firms.