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.

一、英文部分

1、Berkovitch, E. and M. P. Narayanan, 1993, Motives for Takeovers: An Empirical Investigation, Journal of Financial and Quantitative Analysis 28(3), 347-362.

2、Bradley, M., A. Desai, and E. Kim, (1988), “Synergistic Gains From Corporate Acquisitions and Their Division Between the Stock-holders of Target and Acquiring Firm,” Journal of Financial Economics, May, pp.3-40.

3、Firth, M., 1980, Takeovers, Shareholder Returns and the Theory of the Firms, Quarterly Journal of Economics 94, 235-260.

4、Fama, E. F., 1980, Agency Problems and the Theory of the Firm, Journal of Political Economy 88, 288-307.

5、Jensen, Michael C., 1986, Agency Costs of Free Cash Flow, Corporate Finance, and Takeovers, American Economic Review Proceedings 76, 323-329.

6、Lewellen, W., C. Loderer, and A. Rosenfeld, 1985, Merger Decisions and Executive Stock Ownership in Acquiring Firms, Journal of Accounting and Economics 7, 209-231.

7、Malatesta, P., 1983, The wealth effect of merger activity and the objective functions of merging firms, Journal of financial economics 11, 155-181.

8、Morck, R.,A.Shleifer, and R.W.Vishny,1988, “Management ownership and market valuation: an empirical analysis,” Journal of Financial Economics 20,293-315.

9、Roll, R. (1986), “The Hubris Hypothesis of Corporate Takeovers.” Journal of Business, 59, pp. 197-216.

10、Palepu,Bernard,＆Healy,2005,Business Analysis＆Valuation.

二、中文部分

1、伍忠賢(民89年)，「企業購併－理論與實務」，台北新陸書局。

2、李淑芬(民95)，「企業購併前後之經營績效研究」，成功大學高階管理碩士在職專班未出版碩士論文。

3、余尚武及江玉柏(民87)，「影響企業購併成敗之因素與策略探討」，經濟情勢暨評論，第四卷第二期，125-141。

4、吳安妮 (民81)，「台灣企業併購動機之實證研究」，管理評論 11卷，
1-27。

5、吳啟銘(民89)，「企業評價-個案實證分析」，台北智勝文化出版公司。

6、陳錦堂及沈仰斌(民87)，「購併動機之理論與實證：以美國與亞洲之購併歷史為例」，經濟情勢暨評論，第四卷第二期，30-59。

7、黃仁正(民91)，「台灣上市公司併購動機，動機達成程度與經營績效之研究」，東海大學企業管理所未出版碩士論文。

8、彭素貞(民95)，「企業併購策略與併購綜效之實證研究」，台灣科技大學財務金融所未出版碩士論文。

9、楊天龍（民85），「企業購併動機與績效之探討－以台灣1000大製造業為例」，靜宜大學管理科學研究所未出版碩士論文。

10、魏郁華(民95)，「併購動機:台灣實證研究分析」，元智大學財務金融所未出版碩士論文。