股價與匯率升值是否有利於主併者股東?來自G7國家與中國的證據

Do Appreciations in Equity Price and Currency Benefit the Acquirers’Shareholders? Evidence from G7 Countries and China

本研究探討主併公司股價與匯率升值對併購宣告效果與長期股票績效之影響，研究樣本涵蓋G7國家與中國之併購交易。實證結果顯示，若主併公司在併購宣告前股價上漲，則其併購宣告異常報酬與長期股票績效顯著較低，顯示此現象可能與管理者過度自信或股價高估有關。相對地，若主併公司本國的實質有效匯率升值，則與併購後績效呈正向關係，顯示貨幣升值有助於提升購買力與併購效率。進一步的穩健性檢驗支持上述結果。首先，分析進一步區分股價上漲是否源自成長機會或高估因素。其次，採用二階段最小平方法處理主要解釋變數的內生性問題。第三，控制各國在法律起源與股東保護制度上的差異。整體而言，研究結果在不同模型設定下均具穩健性。

This paper examines the impact of appreciation in the stock price and currency of the acquirer on the announcement effect and long-run stock performance of acquisitions using deals from G7 countries and China. The empirical results show that a rise in stock price prior to the acquisition announcement is associated with significantly lower announcement abnormal returns and long-run stock performance, suggesting the presence of managerial overconfidence or overvaluation. In contrast, an appreciation in the real effective exchange rate of the acquirer’s home country is positively associated with post-acquisition performance, indicating that currency strength enhances purchasing power and acquisition efficiency. Further robustness checks confirm these findings. First, additional analysis disentangles stock price appreciation into components driven by growth opportunities versus overvaluation. Second, two-stage least squares regressions address concerns regarding endogeneity. Third, cross-country variations in legal origin and shareholder protection are controlled for. Overall, the results are robust to alternative specifications.