臺灣上市公司實施購回庫藏股與維持目標槓桿比及防禦敵意併購關聯性之實證研究

Abstract

本研究以2000年至2016年間宣告購回庫藏股之臺灣上市公司為樣本，進行槓桿比變化比例與事件期累積異常報酬之迴歸分析，並根據公開資訊觀測站重大訊息公告蒐集「有公告併購消息且為被併購方」之公司，以分析投資人對於「維持目標槓桿比」與「防禦敵意併購」此兩項未於法令明文之庫藏股購回動機之看法。 研究結果發現無論何種產業及槓桿比變化比例，購回庫藏股之宣告效果在各事件期皆具顯著異常正報酬，但槓桿比變化比例與事件期累積異常報酬僅於電子業和槓桿比變化比例大之公司呈顯著負相關。就買回用途而言，以「買回註銷」與「轉讓員工」為買回用途者在各事件期皆具統計顯著正報酬，但槓桿比變化比例與事件期累積異常報酬僅於「轉讓員工」此用途呈顯著負相關。 從槓桿比變化比例與事件期累積異常報酬呈負相關可發現投資人偏好公司將槓桿比維持於一適當範圍內；然而「被併購方」之樣本其事件期累積異常報酬平均數與中位數幾乎不具統計顯著且低於其他類別之樣本，故投資人對於「以購回庫藏股防禦敵意併購」尚無意識。

This study investigates Taiwan listed companies which repurchase treasury shares during 2000 to 2016 and uses regression analysis to find the relationship between the proportion of changes in leverage ratio and cumulative abnormal return of event period. The study also collects information about takeover targets from Market Observation Post System to analyze investors’ opinion about maintaining target leverage ratio and defending hostile takeovers, the motivation of repurchases which aren’t listed in Taiwan’s regulation. The results show that declaration effect of repurchase has statistically significant positive cumulative abnormal return, regardless of industry and changes in leverage ratio. But the proportion of changes in leverage ratio and cumulative abnormal return of event period are statistically significant negative relevant only in electric industry and companies with large changes in leverage ratio. In terms of repurchase purposes, companies use “buy back and write off” and “transfer to employees” have statistically significant positive cumulative abnormal return. However, the proportion of changes in leverage ratio and cumulative abnormal return of event period is only statistically significant negative relevant in “transfer to employees” this category. To summarize, negative relevant between the proportion of changes in leverage ratio and cumulative abnormal return of event period indicates that investors prefer companies maintain their leverage ratio in an optimal range. However, the mean and median of cumulative abnormal return of event period of takeover targets are not statistically significant and even lower than other categories shows that investors may not aware that defending hostile takeover can be one of the motivation of repurchase.