本研究的併購動機主要分為綜效假說、代理假說和傲慢假說。我們以目標公司報酬和總報酬的相關性，以及目標公司報酬和主併公司報酬的相關性來區分此三種假說。併購動機若支持綜效假說，則預期目標公司報酬和總報酬呈正相關，且目標公司報酬也和主併公司報酬呈正相關。併購動機若支持代理假說，則預期目標公司報酬和總報酬呈負相關，且目標公司報酬也和主併公司報酬呈負相關。併購動機若支持傲慢假說，則預期目標公司報酬和總報酬無關，且目標公司報酬和主併公司報酬呈負相關。 　　本研究探討美國88件國內併購案以及79件跨國併購案，樣本期間為2000年1月1日到2006年12月31日。根據本研究的實證結果，做出以下結論： 1、在國內併購案中，併購的動機主要來自綜效假說和傲慢假說。而在跨國併 購案中，併購的動機主要來自代理假說和傲慢假說。 2、沒有足夠的證據顯示以傲慢假說為併購的動機會減少公司的價值。 3、匯率的變動並不影響企業從事跨國併購的動機。 / This paper develops tests to distinguish among the three major motives for M&A：synergy、agency and hubris. We distinguish three hypotheses by observing the correlation between target, acquirer and total gains. If the motive supports the synergy hypothesis, it expects positive correlation between target and total gains. The synergy hypothesis also expects positive correlation between target and acquirer gains. If the motive supports the agency hypothesis, it expects negative correlation between target and total gains. The agency hypothesis also expects negative correlation between target and acquirer gains. If the motive supports the hubris hypothesis, it expects zero correlation between target and total gains. The hubris hypothesis also expects negative correlation between target and acquirer gains. 　　This paper treats 88 domestic and 79 cross-boarder cases of M&A over the period of 2000 to 2006 in America. According to the empirical result of the study, the conclusions are stated as follows： 1. In the domestic cases of M&A, the synergy hypothesis and the hubris hypothesis are the primary motive of M&A. In the cross-boarder cases of M&A, the agency hypothesis and the hubris hypothesis are the primary motive of M&A. 2. It has no adequate proof to show the motive of M&A flows from the hubris hypothesis may decrease the value of the company. 3. The variation of the exchange rate has no effect on the motive of cross-boarder M&A.

本研究係以民國81年1月1日至民國90年12月31日間曾從事併購行為之國內53家上市櫃公司為研究樣本，取其併購前後五年之財務資料，利用資料包落分析法計算其整體技術效率、純技術效率、規模效率值，再依據目標公司是否位於國內為併購類型的分類標準，探討併購活動與併購類型是否影響主併公司績效。 本研究實證結果如下： 一、在不考慮併購類型的情況下，併購前後對於整體技術效率、純技術效率與規模效率呈現不顯著的正向關係，表示併購後效率雖然有提升，但未達顯著水準。 二、在未區別併購前後的情況下，雖然併購類型對於整體技術效率與純技術效率均呈正向關係，與規模效率則呈負向關係，但三種效率值皆未達到統計上顯著水準，表示進行國內併購與跨國併購的主併公司在效率上沒有太大差異。 三、跨國併購後在整體技術效率、純技術效率與規模效率均呈現正向關係，並且在整體技術效率與純技術效率達到統計上顯著水準，表示「國際化網路」假說確實存在。 / In this research, we based on the companies that listed in Taiwan Security Exchange or the OTC which had domestic or foreign acquisitions over the period from 1992 to 2001. Using these firms’ five years financial data before and after acquisitions, we apply Data Envelopment Analysis to measure efficiency and compare the performance of firms following domestic or foreign acquisitions. The major research finding as follows. First, if we do not consider the type of acqusiontion, domestic or foreign, the results denote that there is no efficiency difference before or after acquisitions. Second, after we control before or after acquisitions, the results demonstrate that there is no efference difference between domestic and foreign acquisions. Third, after we control the cross effects between acquisition time and acquisition types, the results show that after foreign acquisitions the merger companies increase efficiency significantly, which confirms “Positive Multinational Network Hypothesis”.