資訊揭露是管理階層向外部投資者傳達公司績效和治理的重要工具，資訊揭露程度越高，將有助於降低資訊不對稱。本研究以2014年1月1日至2017年12月31日台灣五十上市公司作為研究對象，並區分台灣股票市場交易人為三大機構法人與散戶投資人。採用Weber and Camerer (1998)所提出計算處分係數之方式，檢驗各類投資人是否具有處分效果。接著，以第一屆至第四屆 (2014-2017)公司治理評鑑結果與買賣價差作為資訊揭露之代理變數，進一步探討資訊揭露程度是否可以減緩各類別投資人之處分效果。實證結果顯示，散戶投資人與三大機構法人皆具有處分效果，且散戶投資人處分效果大於三大機構法人。其次，在公司治理評鑑方面，三大機構法人與散戶投資人在公司治理揭露程度較佳或較不佳之公司，都具有處分效果。此外，三大機構法人雖顯示公司治理較佳的處分效果較大，但經過Wilcoxon 符號順序檢定和T檢定後無法證實公司治理揭露佳之處分效果大於公司治理揭露較不佳。最後，以買賣價差做為區分，三大機構法人及散戶投資人在買賣價差不同時皆存在處分效果。經過差異性檢定也證實三大機構法人及散戶投資人在買賣價差較大的公司，其處分效果較為強烈。 Information disclosure is an important tool for managers to convey corporate performance and corporate governance to external investors. The higher the level of information disclosure, the lower the information asymmetry is.The study includes Taiwan 50 Index from Jan. 1, 2014 to Dec. 31, 2017. The sample of the investors is divided into institutional investors and individual investors. First, we employ the disposition coefficient approach proposed by Weber and Camerer (1998) to test the disposition effect of all kinds of investors in the Taiwan stock market. Then, we use the results of the first to fourth corporate governance evaluation (2014-2017) and bid-ask spreads as the proxy variables of information disclosure to discuss whether information disclosure can reduce the disposition effect of investors.The empirical results show that both institutional investors and individual investors have disposition effect and the disposition effect of individual investors is the strongest. Moreover, institutional investors and individual investors show the disposition effect no matter what degree of the results of corporate governance evaluation. Although institutional investors show that in high corporate governance evaluation company have the disposition effect, it fails to prove that sound corporate governance disclosure is better than that of unsound corporate governance after using Wilcoxon sign-rank test and T-test. Finally, investors have the disposition effect no matter what degree of bid-ask spreads they have. It also shows that institutional investors and individual investors have a strong disposition effect in highly bid-ask spreads companies.
