80年代开始，大量的国际贸易都是在一些大公司的控制下进行的，这一事实已经受到广泛注意，同时很大比例的国际贸易都与直接投资有关，或者发生在公司的内部〔1〕。随着越来越多的国际贸易在公司内部进行，市场的作用逐渐被淡化。这种国际贸易现象反映了公司存在回避外部市场（arm’s—length market）的动机。 我们认为对市场本身效率和交易成本等问题的研究应该成为国际贸易理论的重要课题，而目前学术界对这个问题的研究和重视远没有达到应有的程度。

一、不完全竞争与国际贸易理论
二、公司内国际贸易提出的问题
三、市场效率、交易成本与“内部化”
四、对公司内贸易的一些分析
五、国际贸易理论和直接投资理论的融合
六、总结

〔1〕要准确的估算国际贸易和直接投资的联系并非容易， 但是一般估计目前60～70％的国际贸易与直接投资直接或间接有关。
〔2〕较为重要的文献有：Krugman（1979，1980，1981）， Dixit& Norman （1980），Brander（1981），Brander ＆ Spencer （1981）。
〔3〕See Brander & Krugman (1983).
〔4〕See "US Direct Investment Abroad" in Survey of CurrentBusiness US Department of Commerce.
〔5〕See Grubel & Lloyd (1975,pp. 114～118).
主要参考资料：
〔1〕Grubel, H.G. and Lloyd, P.J.(1975) , Intraindustrytrade: The theory and measurement of international trade indifferentiated products, London: Macmillan.
〔2〕Krugman, P.R. (1979), "Increasing returns, monopolis-tic competition, and international trade" Journal of Internat-ional Economics, Vol. 9, pp.469～479.
〔3〕Dixit, A. K. and Norman, V.D. (1980), The Theory ofInternational Trade. Cambridge: Cambridge university Press.
〔4〕Krugman, P.R. (1980), "Scale economies, Product diff-erentiation, and pattern of trade", American Economic Review,Vol. 70, pp.950～959.
〔5〕Krugman, P.R. (1981), "Intraindustry specializationand the gains from trade", Journal of Political Economy, Vol.89 pp.959～973.
〔6〕Brander, J.A. (1981), "Intraindustry trade in identi-cal commodities", Journal of International Economics,Vol.11,pp. 1～14.
〔7〕Brander, J.A. and Spencer, B.J. (1981) "Tariffs andExtraction of Foreign Monopoly Rents under Potential Entry",Canadian Journal of Economics 14, No. 3, pp. 371～389.

〔8〕Marshall, A (1920), Principles of economics, 8th ed., London: Macmillan.
〔9〕Stigler, G.J. (1951), "The division of laboris limit-ed by the extent of the market" Journal of Political Economy,Vol. 59, pp. 185～193.
〔10〕Helpman, E. (1981), "International trade in the pre-sence of product differentiation, economies of scale and mon-opolistic competition: a Chamberlin Heckscher－Ohlin approach", Journal of International Economics, Vol. 11, pp.305～340.
〔11〕Ethier, W.J.(1982), "National and international ret-urns to scale in the modern theory of international Trade"American Economic Review, Vol. 72, pp. 389～405.
〔12〕Brander, J.A. and Krugman, P.R. (1983), "A reciproc-al Dumping model of international trade", Journal of Internat-ional Economics, Vol. 15, pp. 313～321.
〔13〕Dunning, J.H. (1984), "Japanese participation inthe UK Manufacturing indrstry: a report prepared for theDepartment of Industry", mimeo.
〔14〕Lecraw, D.J. (1985), "Evidence on transfer pricingby TNCs", In A, M. Rugman (ed.) Transf..