本研究主要目的為檢驗機構投資人在新上市票交易是否為一訊息交易者，據此本研究假定投資者分為過度樂觀與過度悲觀的情緒性的個人投資者，以及存在訊息優勢的機構投資人。本文以四因子模型檢驗機構投資人高持股比例之IPOs是否具有長期正的超額報酬。再者，若個人投資者是具有情緒性，則發行淡旺季將會影響個人投資者，進而影響機構投資人持股策略；最後，為排除承銷商安定性操作影響股票報酬，因此本研究以上市四周後的第一個季報日作為公司訊息揭露的時點，如果機構投資人是訊息優勢的交易者，則在公司財務季報揭露日，股票報酬與機構投資人持股比例必定呈現顯著的正向關係。實證結果發現：即使機構投資人所握有高持股比例之新上市股票，一至三年期依舊存在負的報酬；此外，在控制特徵變數後，股票發行旺季時機構投資人在季報日採低持股比率將獲得高報酬，淡季時採高持股比率策略將獲得高報酬，機構投資人持股策略在淡旺季的確不同，然而機構投資人持股比例與股票報酬關係在淡旺季均不具檢定的顯著性。綜合上述，無充分證據顯示機構投資人在台灣新上市股票市場是訊息交易者。

This paper investigates the long-run performance of IPOs held by institutions .Specifically, we assume there are two types of investors. The first type is sentiment investors, presumably individuals, who are prone to excessive optimism or pessimism. The other type of investors, presumably institutional investors, possesses an informational advantage. Thus the cross sectional variation in institutional ownership reflects institutional valuations of firm. Furthermore, if the investment opportunity in 'cold' and 'hot' periods differ substantially, we would expect the ratio of IPOs stocks held by institutional investors to vary from period to period. To evaluate IPOs performance, we use the three factors and momentum factor. We find that the IPOs in highest institutional ownership quintile perform poorly when factor returns are used. Although the relation between institutional holdings and subsequent performance vary over time, there is no evidence that institutional investors are informed traders in Taiwan IPOs market.