本研究針對2000年至2017年間，曾買回庫藏股之台灣上市(櫃)公司為研究樣本，採用事件研究法探討買回庫藏股宣告日前後，其普通股價格是否存在顯著之異常行為，並再分別針對金融海嘯前後期間進行比較分析，以及進一步討論買回用途、買回執行率或買回次數對其宣告前後股價行為之影響。
結果顯示在買回庫藏股宣告日前存在顯著小於零之平均異常報酬；在宣告日後，存在顯著大於零的平均異常報酬。顯見股價於宣告前存在低估之現象，隨後股價持續正向反應庫藏股買回之宣告訊息。此顯示買回庫藏股存在資訊內涵，經理人經由公開市場買回股票的方式向市場傳遞股價低估或對未來現金流量的信心，因此是好消息，這促使投資人進場購買股票，並將股價推升至合理價位，這支持訊息傳遞假說。而此結論並不會受到金融海嘯前後不同之研究子期間的影響，以及股價對買回庫藏股宣告的反應程度並不會受到不同買回用途、買回執行率高低和第幾次宣告買回等因素之影響。

This study used the event study method to explore whether there is significant abnormal price behavior around stock repurchases of Taiwan listed companies from 2000 to 2017. Then compare and analyze the period before and after the financial tsunami, and further discuss the impact of usages, executed rates or buying times of stock repurchases.
The results show that the average abnormal returns is significantly less than zero before the announcement date of the stock repurchase, and the average abnormal return is significantly greater than zero after the announcement date. It is obvious that the stock price is undervalued before the announcement, and then the stock price continues to be positively responding to the announcement of the stock repurchased. This shows that there is information content in the stock repurchase. Managers convey the stock price undervalued or the confidence in future cash flow by buying back shares in the open market, so it is a good news, which prompted investors to enter the market to buy stocks, and the stock price pushing up to a reasonable price, this supports the signal hypothesis. This conclusion will not be affected by the different research period before and after the financial tsunami, and the degree of reaction of the stock price to the repurchase of treasury stocks will not be affected by factors such as usages, executed rates or buying times of stock repurchases.

內容目錄
內容目錄.................................................I
表目錄.................................................II
圖目錄................................................III
第一章緒論...............................................1
第一節研究背景與動機......................................1
第二節研究目的...........................................3
第三節研究架構...........................................4
第二章文獻探討...........................................6
第一節庫藏股定義.........................................6
第二節庫藏股相關法規及程序................................7
第三節相關文獻回顧......................................10
第三章研究方法..........................................18
第一節研究設計與事件研究法...............................18
第二節研究假說..........................................24
第三節資料來源、研究期間與樣本............................25
第四章實證結果與分析.....................................29
第一節全體樣本..........................................29
第二節金融海嘯前後......................................35
第三節買回用途..........................................41
第四節買回執行率........................................46
第五節買回次數..........................................51
第五章研究結論..........................................56
參考文獻................................................59
表目錄
表3-1 2000年至2017年間宣告買回庫藏股之上市(櫃)公司樣本表：買回用途.................................................26
表3-2 2000年至2017年間宣告買回庫藏股之上市(櫃)公司樣本表：買回執行率...............................................27
表3-3 2000年至2017年間宣告買回庫藏股之上市(櫃)公司樣本表：買回次數.................................................28
表4-1 平均異常報酬(%)：全體樣本..........................32
表4-2 累積平均異常報酬(%)：全部樣本......................33
表4-3 平均異常報酬（%）：金融海嘯前後.....................38
表4-4 累積平均異常報酬（%）：金融海嘯前後.................39
表4-5 平均異常報酬（%）：買回用途........................43
表4-6 累積平均異常報酬（%）：買回用途.....................44
表4-7 平均異常報酬（%）：買回執行率.......................48
表4-8 累積平均異常報酬（%）：買回執行率...................49
表4-9 平均異常報酬（%）：買回次數........................53
表4-10 累積平均異常報酬（%）：買回次數....................54
圖目錄
圖1-1 本研究流程.........................................5
圖3-1 研究設計流程圖....................................18
圖3-2 事件研究法時間關係圖...............................19
圖4-1 平均異常報酬(%)：全部樣本..........................34
圖4-2 累積平均異常報酬(%)：全部樣本......................34
圖4-3 平均異常報酬(%)：金融海嘯前後......................40
圖4-4 累積平均異常報酬(%)：金融海嘯前後...................40
圖4-5 平均異常報酬(%)：買回用途..........................45
圖4-6 累積平均異常報酬(%)：買回用途......................45
圖4-7 平均異常報酬(%)：買回執行率........................50
圖4-8 累積平均異常報酬（%）：買回執行率...................50
圖4-9 平均異常報酬（%）：買回次數........................55
圖4-10 累積平均異常報酬（%）：買回次數....................55

中文文獻
1. 陳韋志 (2009)，「機構投資人持股比例及持股變動與庫藏股宣告效果關聯性之研究」，國立高雄第一科技大學財務管理所碩士論文。
 
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