本文之研究期間為2000年1月至2005年12月為止，以153家於這段期間曾從事購併的上市(櫃)公司為研究對象，主要是探討其從事購併活動後之長期投資績效與長期營運績效。長期投資績效分析結果顯示無論採用何種方法衡量，所獲取之長期平均異常績效均為正值，此似乎意謂著投資者若於公司購併後購買股票且長期持有，其平均報酬優於基準之平均報酬。 長期營運績效之分析結果顯示台灣上市(櫃)公司於購併後，其平均獲利能力是呈現逐年衰退之現象，且顯著低於同產業，即其獲利能力相對較差。但是購併卻能提升主併公司總資產週轉率，即能夠提高資產之使用效率。最後，結果顯示台灣上市(櫃)公司於購併後，其平均資本結構並未出現顯著之變化。 This thesis was conducted during January 2000 till December 2005, based on the 153 M&A announcement samples in Taiwan Stock Exchange Corporation and Over-the-Counter Market (TSEC&OTC) performances. The empirical results show that regardless of which method the average abnormal performance were showed up in the long run, if the investors purchase this company stock and hold for long-terms after the M&A, the average returns is better than standard. The Long run operating performance results show that Taiwan Stock Exchange Corporation and Over-the-Counter Market (TSEC&OTC) after M&A the profitability drops every year, and present significantly lower than the other same industries, which means in poor profitability. In the other hand, merger is able to enhance the principal company and return on total assets. In the end, the result simply shows the asset structure after M&A has no significant changes in Taiwan.
