臺灣博碩士論文加值系統

　　本研究探討在古諾(Cournot)市場、同質廠商與線性需求函數的假設下，最適的結合組織成員數，以及結合組織對社會福利的影響。
　　研究結果顯示，不論市場規模的大小，若對結合行為的處罰不存在，則結合組織將有動機勾結市場上的所有廠商達到獨占以獲取最大利潤。若將結合行為的外部性視為結合組織必須面對的處罰，則結合組織在成立時考慮的就不只是利潤，同時也會考慮它必須面對的處罰而間接考慮社會福利的變化，進而促使結合組織僅會結合市場上 34% 的廠商而非所有廠商來獲取最高利潤，同時增加社會福利。簡單的說，透過對結合組織的處罰，結合行為的外部性因而被內部化。所以，若一個結合組織會成立，則該結合組織對社會福利必然有益，一個對社會福利有害的結合組織則一定不會成立。
　　另外，一個結合組織若要對社會福利有益，則其市場佔有率就不能太高。然而，一個市場占有率不高的結合組織並沒有辦法使其成員廠商在結合後擁有較結合前更高的利潤。若廠商在結合後無法獲取更高的利潤，則廠商就沒有動機成立結合組織。因此，對社會福利有益的結合組織未必會成立。本模型中的結合組織即是因此而皆不會成立，即使是考慮對結合行為的處罰後仍對社會福利有利的結合組織，因為其偏低的市場占有率無法使其成員廠商在結合後較結合前獲取更高利潤。此外，市場規模的大小對結合組織的成立與否也有很大影響，因為市場規模愈大，結合組織的必須市場佔有率就愈高，因此，市場規模愈大，結合組織就愈難成立。

This paper is based on linear demand and traditional Cournot model. There are n identical firms in a market producing homogenous goods.
The results of this paper show that no matter what the size of a market is, a cartel will collude with all firms in a market to make the highest profits when there is no sanction. When the externality of collusion is viewed as sanction and imposed on a cartel, the cartel will take profits and social welfare into consideration simultaneously. Thus a cartel will collude with 34% of firms instead of all firms in the market to not only make the highest profits but also create the highest social welfare. That is, the externality of collusion is internalized by the sanction. Therefore, if a cartel is formed, then the cartel is efficient, while a cartel will not be formed if it is inefficient.
If a cartel is efficient, the market share of it must be small. However, the required market share of a cartel has to be large enougha cartel to with small market share can not make its member firms more profitable than how they are when they do not participate in the cartel. Without higher profits, firms are lack of incentives to collude. Thus an efficient cartel will not necessarily be formed. Therefore,That is also the reason why no cartel in our model will be formed in every size of the market even though the cartel itself is profitable and socially desired after the sanction is imposed. Moreover, the size of a market is also crucial to collusion because the bigger a market is, the larger the required market share of a cartel has to be. Therefore, the bigger the market is, the harder the cartel is formed.

CHINESE ABSTRACT....................................................I
ABSTRACT...........................................................II
INDEX.............................................................III
1. INTRODUCTION.....................................................4

2. THE MODEL........................................................5
2.1. STAGE 1........................................................5
2.2. STAGE 2........................................................6
2.3 COMPARISON......................................................7
2.3.1 Quantity......................................................7
2.3.2. Profit.......................................................8
2.3.3 Market equilibrium............................................9

3. DISCUSSION ON SOCIAL WELFARE AND SANCTIONS......................11
3.1 DEFINITION OF OPTIMAL SANCTION AND EFFICIENCY..................11
3.2 THREE MAJOR ISSUES.............................................18
3.2.1 A sufficient condition for firms to collude..................18
3.2.2 Change of net external social welfare........................20
3.2.3 Sanction.....................................................22
3.3 CONFIRMATION...................................................24

4. OPTIMAL NUMBER OF FIRMS TO COLLUDE AND TWO IMPORTANT RESULTS....25

5. LIMITATIONS IN THIS STUDY AND SUGGESTIONS FOR FUTURE RESEARCH...26

6. CONCLUSION......................................................27

APPENDIX A TABLES..................................................29

APPENDIX B EQUATIONS...............................................37

REFERENCE 39

Becker, G.S., 1968. Crime and punishment: an economic approach. Journal of Political Economy 76, 169–217.

Cabral, M.B., 2003. Horizontal mergers with free-entry: why cost efficiencies may be a weak defense and asset sales a poor remedy. International Journal of Industrial Organization 21, 607-623.

Cooter, R. and Ulen, T., 2004, Law and economics, Pearson Addison Wesley, Reading, Massachusetts.

Daughety, A.F., 1990. Beneficial concentration. American Economic Review 80, 1231–1237.

Farrell, J., Shapiro, C., 1990. Horizontal mergers: an equilibrium analysis. American Economic Review 80, S. 107-126.

Farrell, J., Shapiro, C., 1991. Horizontal mergers: reply. American Economic Review 81, 1007-1011.

Faul´ı-Oller, R., 1997. On merger profitability in a Cournot setting. Economics Letters 54, 75–79.

Grossman, S. J., Oliver D.H., 1980. Takeover bids, the free-rider problem, and the theory of the corporation. Bell Journal of Economics, 42-64.

Gugler, K., Mueller, D., Yurtoglu, B., Zulehner C., 2003. The effects of mergers: An international comparison. International Journal of Industrial Organization 21, 625-653.

Horn, H., Persson, L., 2001. Endogenous mergers in concentrated markets. International Journal of Industrial Organization 9, 1213-1244.

Hovenkamp, H., 1994, Federal antitrust policy, MN: West Publishing Co., St. Paul.

Johan, S., Röller, L-H., Verboven, F. 2001. Efficiency gains from mergers. European Economy 5, 31-128.

Kimmel, S., 1992. Effects of cost changes on oligopolists’ profits. Journal of Industrial Economics 40, 441–449.

Lahiri, S., Ono, Y., 1988. Helping minor firms reduces welfare. The Economic Journal 98, 1199–1202.

Landes W.M., 1983. Optimal sanctions for antitrust violations. University of Chicago Law Review 50, 652-678.

Marius, S., 1989. Investment in oligopoly: welfare effects and tests for predation. Oxford Economic Papers 41, 4, 698-719.

McAfee, R.P., William, M.A., 1992. Horizontal mergers and antitrust policy. Journal of Industrial Economics 40, 2, 181-187.

Mueller, D.C. 1989. Mergers: causes, effects and policies. International Journal of Industrial Organization 7, 1-10.

Mueller, D.C., 1997. Merger policy in the United States. Review of Industrial Organization 12, 655-685.

Perry, M.K., Porter, R.H., 1985. Oligopoly and the incentive for horizontal merger. American Economic Review 75, 219-227.

Posner, R.A., 1975. The social costs of monopoly and regulation. Journal of Political Economy 83, 807-27.

Ravenscraft, D.J., Scherer, F.M., 1989. The profitability of mergers. International Journal of Industrial Organization 7, 106-116.

Salant, S.W., Switzer, S., Reynolds, R.J., 1983. Losses from horizontal merger: the effects of an exogenous change in industry structure on Cournot-Nash equilibrium. Quarterly Journal of Economics 98, 185-199.

Salant, S.W., 1987. Triple damage awards in private lawsuits for price fixing. The Journal of Political Economy 95, 6, 1326-1336.

Schmalensee, R., 1989. Is more competition necessarily good? Industrial Organization Review 4, 120–121.

Selten, R., 1973. A simple model of imperfect competition, where 4 are few and 6 are many. International Journal of Game Theory 2, 3, 141-201.

Stigler, G.J., 1964. A theory of oligopoly. The Journal of Political Economy 72, 1, 44-61.

Stigler, G.J., 1966. The economic effects of the antitrust law. Journal of Law and Economics 9, 225-258.

Stigler, G.J., 1970. Optimum enforcement of law. Journal of Political Economy 78, 3, 526-536.

Souam, S., 2001. Optimal antitrust policy under different regimes of fines. International Journal of Industrial Organization 19, 1-26.

Werden, G.J., Baumann M.G., 1986. A simple model of imperfect competition in which four are few but three are not. The Journal of Industrial Economics 34, 3, 331-335.

Werden, G.J., 1991. Horizontal mergers: comment. American Economic Review 81, 1002-1006.

Williamson, O.E., 1968. Economics as an antitrust defense: the welfare tradeoffs. American Economics Review 58, S. 18-36.

Zhao, J., 2001. A characterization for the negative welfare effects of cost reduction in Cournot oligopoly. International Journal of Industrial Organization 19, 455-469.

Ziss, S., 2001. Horizontal mergers and delegation. International Journal of Industrial Organization 19, 471-492.