| Abstract: | 本研究探討公司宣告實施庫藏股的股價反應 (即宣告報酬) 的影響因素，聚焦在過去購回完成率與過去公司治理的影響。本文推測過去公司治理會影響過去的完成率，故尚無法確定其是否真會影響後續購回案之宣告效果，因此需檢視過去公司治理的角色。樣本是台灣上市上櫃公司於2000年9月到2020年底所公告買回股票的事件，以事件研究法估計宣告異常報酬，使用橫斷面迴歸分析做假說檢定，包括：一、公司治理正向影響近期購回完成率；二、過去的公司治理正向影響後續購回宣告的股價反應；三、考慮過去公司治理後，過去完成率對後續購回宣告報酬的影響不顯著。結果發現，假說一成立，完成率受購回宣告前季公司治理綜合指標與董事會獨立性之正向影響。在確認過去完成率正向影響購回宣告報酬後，發現宣告報酬不受過去綜合治理指標影響，但受過去內部人持股正向影響及機構持股率負向影響。因此假說二僅在部分個別治理變數下成立。考慮過去治理變數後，雖過去治理綜合指標不影響宣告報酬，但過去完成率影響之顯著性減弱；若考慮個別治理變數，過去完成率雖仍正向影響宣告報酬，但顯著性也變弱；過去內部人持股有顯著正向影響，過去機構投資人持股有負向影響。因此假說三在這兩個治理變數上部分成立。總之，過去完成率具內生性，過去完成率對後續購回宣告報酬之影響受其同期公司治理機制的內部人持股率與機構持股率之衝擊。這顯示公司治理的重要性，其對公司價值與股票購回政策的資訊內涵誠值得重視。
This study explores the influencing factors of the stock price response (that is, announcement returns) for the announcement of company’s treasury stock repurchases, focusing on the impact of past repurchase completion rates and past corporate governance. This article speculates that the past corporate governance will affect the past completion rate, so it is still uncertain whether it will actually affect the announcement effect of subsequent repurchase cases. Therefore, it is necessary to examine the role of past corporate governance. The sample is a Taiwan-listed and OTC firms that announced stock repurchase from September 2000 to the end of 2020. The event study method is used to estimate the announcement abnormal returns, and the cross-sectional regression analysis is used to test the hypotheses, including: 1. Corporate governance positively affects the recent repurchase completion rate; 2. Past corporate governance positively affects the stock price response of subsequent repurchase announcements; 3. After considering the past corporate governance, the past completion rate has no significant impact on the subsequent repurchase announcement returns.The findings are that the first hypothesis is held, and the completion rate is positively affected by the comprehensive indicator of corporate governance and the independence of the board of directors in the previous quarter of the repurchase announcement. After confirming that the past completion rate positively affected the repurchase announcement returns, it is found that the announcement returns are not affected by the past comprehensive governance indicator, but are positively affected by the past insider shareholdings and are negatively affected by the past institutional shareholdings. Therefore, Hypothesis 2 is only valid under some individual governance variables. After considering the past governance variables, although the past comprehensive governance indicator does not affect the announcement returns, the significance of the impact of the past completion rate is weakened. If individual governance variables are considered, although the past completion rate still positively affects announcement returns, its significance has also become weaker; and the past insider shareholding has a significant positive impact, and the past institutional investor shareholding has a negative impact. Therefore, Hypothesis 3 is partially established on these two governance variables. In short, the past completion rate is endogenous, and the impact of the past completion rate on the subsequent repurchase announcement returns is affected by the insider shareholding and institutional shareholding of the corporate governance mechanism on the same period. This shows the importance of corporate governance, and its information content on firm value and stock repurchase policies are truly worthy of attention. |
