金融機構併購銀行對股東財富之影響-以事件研究法分析

台灣的銀行隨著國際發展趨勢，邁向金融機構大型化或專業化已是不可抵擋的潮流。公司常藉由併購此外部成長策略作為業務及規模擴張的管道，並獲取更多管理經驗以及經營資源。台灣於2000年通過《金融機構合併法》，2001年施行《金融控股公司法》，鼓勵金融機構進行併購推動台灣金融業迅速擴大規模，希望未來促成三至五家金融機構成為亞州具指標性之區域性金融機構。在企業併購案件中，主併公司及目標公司是否真能因併購活動而對股東財富產生影響，主併銀行在併購宣告日後是否會如過去文獻中產生負的異常報酬，目標公司在併購宣告日後是否會如過去文獻中產生正的異常報酬。本研究以2002年至2019年間揭露宣告併購之台灣證券交易所上市之金融控股及銀行為研究對象，有效樣本數共七件，採取事件研究法，使用雙指標市場模式探討宣告日對主併銀行及目標銀行股票異常報酬率之影響，並進行實證研究分析。研究結論如下: 國內之目標銀行僅有一家在併購宣告當日具有顯著正向累積異常報酬。其餘皆呈現不顯著的異常報酬率及累積異常報酬率，與過去文獻不符。探究其原因可能為投資人對於公司併購時，其資本結構將變動採取保守心態及作為，使得股市提前反應。併購消息具有半強式效率市場特質，顯示一般投資人難以在併購消息後獲得超額報酬，以致於事件日時無顯著地異常報酬及累積異常報酬產生。

關鍵字

併購；事件研究法；異常報酬；累積異常報酬

並列摘要

Following globalization trends, Taiwan's banks have increased their scale or specialized. Taiwan’s government passed the "Financial Institutions Merger Act" in 2000 and the "Financial Holding Company Law" in 2001 to encourage financial institutions to rapidly expand Taiwan's financial industry through mergers and acquisitions (M&A). The government hoped that these acts and other policies would lead to the development of three to five Taiwanese financial institutions becoming top Asian banks in the future. A question that arises from M&A activity is whether acquiring companies and target companies really increase shareholder value. Consequently, I examined whether acquiring banks have negative abnormal returns on the announcement day and whether the target banks have positive abnormal returns on the announcement day. The research sample comprised seven M&A activities between financial holding companies and banks listed on the Taiwan Stock Exchange from the year 2002 to 2019. I use the dual-index market model and event study approach to study the impact of the announcement date on the shareholders’ value of the acquiring companies and target companies. Results show that only one of the domestic target banks had significant positive cumulative abnormal returns on the day of the M&A announcement. The other activities showed insignificant abnormal returns and cumulative abnormal returns, which are inconsistent with the existing literature. Reasons no significant abnormal returns and cumulative abnormal returns occurred on the day of the event might be the investor adopted a conservative attitude and behavior when the company's mergers and acquisitions would change its capital structure, or internal information leaked to the market before the event date, or insiders made prior transactions.