本研究以2015年至2019年第一次宣告買回庫藏股之上市與上櫃公司為研究樣本，透過事件研究法分析公司股價變化於公司宣告日後之表現，並進一步觀察股價報酬與公司未來經營績效的關聯性。依據本研究實證結果，發現公司在宣告執行庫藏股買回計畫前股價呈現負向累積異常報酬，在公司宣告執行庫藏股買回計畫後，產生顯著正向累積異常報酬，顯示宣告庫藏股買回計畫具有訊號發射效果，並在短期內確實有助於股價之拉抬，另外，在公司未來績效表現方面，公司宣告實施庫藏股所產生累積正向異常報酬將須透過公司執行的程度才能使公司短期績效產生正面影響，故當公司實際執行庫藏股買回比率越高時，將提升公司未來績效表現，可能是台灣上市櫃公司以透過庫藏股買回計畫作為增加投資大眾信心的其一方法，並以此方式捍衛股價維持一個支撐力道，另一方面，公司亦同時透過累積異常報酬的大小與實際執行庫藏股買回程度作為宣示對未來營運績效成長的強度，使其產生對公司經濟實質面的正面支撐。綜上所述，本研究認為公司係透過實施庫藏股買回計畫以傳遞對未來績效的良好預期，因此支持訊號發射假說。

This study uses the listed firms that announced the repurchase of stocks for the first time from 2015 to 2019 as the research samples, and analyzes the performance of the corporation’s stock price changes after the announcement through the event study, and further observes the stock price compensation and the corporate performance.
Based on the results of this research, it is found that the corporation’s stock price showed negative cumulative abnormal returns before the announcement. After the announcement, significant positive cumulative abnormal returns were generated, indicating that the announcement of the stock repurchase plan has a signal launch effect and will indeed help the stock price in the short-term.
In addition, in terms of the corporation 's future performance, the company announced the extent to which the accumulated positive abnormal returns generated by the implementation of treasury stocks will be executed by the company in order to have a positive impact on the corporation’s short-term performance, when the corporation’s implementation of the treasury stock buyback ratio is higher, it will improve the corporation’s future performance.
On the other hand, the corporation uses the accumulated abnormal returns and the actual implementation of treasury stock buybacks as a declaration of the strength of future operational performance growth. This research believes that the corporation is implementing a treasury stock buyback plan to deliver good expectations for future performance, and supports the signaling hypothesis.

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