內部人股權質押為公司治理相關研究常見的議題，而過往研究多著重於內部人若進行股權質押，其後續在執行公司決策時會有什麼樣的影響，在這樣情況下所作出的決策對於外部人而言又會如何，有別於過去研究多以公司本身為主體，本研究將從外部人之觀點來看投資人是如何看待內部人股權質押這一行為，而內部人的股權質押行為在市場上的影響力究竟為何？
本研究首先以主管機關之角度檢視，利用公司法第一百九十七條之一針對股權質押相關限制的修法前及修法後進行比較，探討內部人股權質押這一行為在法規的修改過後是否有達到主管機關之修法要旨，經由本研究實證發現，在法規開始施行後，內部人的累積質押比例確實和法規修改之前相比有下降之趨勢，而大股東與外部投資人間的代理問題也在法規修改後獲得改善，顯示該法條之修正確實有達到其修法要旨，改善企業過度質押之情事。
除了從法規面進行檢視，本研究利用事件研究法來看內部人股權質押行為是否在市場上對外部投資人產生影響力，在什麼樣的情況之下會讓外部投資人將該次的質押行為視為正向消息，經由本研究之實證發現，內部人在進行股權質押前，市場之異常報酬普遍為負，但是在股權設定質押申報日過後，市場上的異常報酬轉正，透過累積異常報酬進行檢視發現當內部人在質押事件前後之持股有增加時，市場對此呈現正向反應，可見內部人在進行股權質押過後的加碼行為讓外部投資人視其為一正面訊號，而針對企業的代理問題程度，外部投資人僅在長期之下才會關注於企業的代理問題是否嚴重，在代理問題程度低的情況下，外部投資人也是給予正面看法，此外，內部人之身分特質和在當次股權質押行為中內部人之質權人對象也是外部投資人所關注之項目，於不同的時點在市場上有不一樣的影響力。
本研究以目前文獻較少探討的部分，由外部人之觀點來看內部人的股權質押行為對於市場之影響究竟為何，從法規面以及投資面的角度檢視內部人股權質押之意涵，填補目前質押相關議題所較少探討之層面，並由本研究之實證對後續研究提出看法及建議。

Insiders’ share pledging behavior is a common issue in the research of corporate governance. In the past, most of research were emphasis on how will insiders’ share pledge behavior influence the enterprise’s decision making. What would these decisions affect investors’ benefit? Different from previous research, this article presented from outsiders’ point of view, what will be the investors’ reaction on insiders’ share pledging behavior and how will this behavior affect on stock market.
First, this article showed that from the point of government, does the amend in Taiwan Corporations Act make the insiders’ share pledging behavior lighter? Also, after the amending, whether the problem of agency problem have been ameliorated? Based on result, it showed that after the amendment of Taiwan Corporations Act, the insiders’ share pledge had become less compared to early period which the Taiwan Corporations Act had not been amended. This result showed that the amendment of Taiwan Corporations Act really ameliorated the insiders’ share pledging behavior. At the same time, the degree of agency problem had become lighter after the amendment.
Besides from the point of amendment, this research also demonstrate that from outside investors’ aspect, what would be the investors reaction to insiders’ share pledging. This article found out that before insiders pledging their shares, the abnormal return was negative. However, after the company released this news on the market, the abnormal return had changed to positive. Also, when insiders increased his or her share holding after they pledged, the outsiders took this as a good information. For agency problem, the outsiders would only noticed the degree of agency problem on the long term investing. If the degree of agency problem were less, the investors would also took this information as a good news. Moreover, this research also demonstrate whether the investors will noticed insiders’ position and the identity of pledgee. The result showed that the position of insiders and pledgee also influence outsiders point of view on insiders’ share pledging event.
Compared to the previous literature, this research demonstrated that from the point of outside investors, how do they react to the insiders’ pledging behavior? From the point of amendment and investors, this research made up for what relative research didn’t mention about and provided some ideas for the follow up research.

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