股票買回是管理當局重要的溝通工具,然而許多公司卻只向市場宣告股票買回計畫,卻未實際買回原先宣告之股數,因此股票買回宣告是否能作為溝通的工具,仍有其不確定性。本研究以公司過去股票買回計畫實際執行紀錄作為後續買回宣告可靠性之代理變數,探討公司過去買回紀錄對後續買回宣告資訊內涵之影響。實證結果顯示,公司股票買回宣告之異常報酬和過去股票買回之執行紀錄呈現顯著正相關,顯示公司過去實際買回股票之紀錄,將影響未來股票買回之宣告效果。此外,研究結果並未發現宣告後之長期異常報酬顯著異於零;換言之,市場參與者並未長期低估公司買回宣告及過去實際買回股票紀錄之資訊內涵。
Managers use stock repurchases to communicate with investors. However, firms announcing repurchasing programs are not obligated to buy back all shares they claimed. Therefore, the information content of repurchasing announcements is unknown as they announced. Using track records from previous buy back data as the proxy for the credibility of announcements, we find that abnormal returns around repurchasing announcements are positively related to the track records, supporting that the track records influence the perceived credibility of subsequent announcements. In addition, we do not find positive long-term abnormal returns following announcements, indicating that market participants do not underreact to the information content conveyed by announcements in the long-run.