本研究以1995年至2003年間，102個上市（櫃）公司合併宣告樣本，使用累積異常報酬法衡量我國上市（櫃）公司合併宣告後，股票報酬之變化情形。首先，短期投資績效之分析結果指出，主倂公司於合併宣告日當天確實存在有顯著為正的異常報酬，但此異常報酬在宣告日後2天逐漸轉為負值。其次，本研究在長期投資績效的分析結果顯示，若使用累積異常報酬法，則主倂公司之合併宣告會存在顯著大於零之累積平均異常報酬；最後，由進一步的分析發現，電子業長期的合併宣告效果，存在顯著大於零的異常報酬，此結果顯示電子業之合併活動，似乎是以追求股東財富極大化為前提進行。
This study applies various measurement models to investigate the long-run performance of 102 merger announcement samples in Taiwan for the period from 1995 to 2003. It is found that merger announcement appear significantly positive abnormal returns around the merger announcement date, but these positive stock returns have changed to significantly underperformance after two days of announcement date. By further analyzing, it is also found that long-run merger announcement effects are positive significantly in electronic industry. The results imply to show that merger announcements are motivated by the maximization of shareholder wealth.
