最適貿易政策、Cournot競爭與水平異質

Optimal Trade Policy under Cournot Competition with Horizontal Differentiation

10.6277/ter.2009.372.3

梁文榮(Wen-Jung Liang)；林晏如(Yen-Ju Lin)

最適貿易政策 ； Cournot競爭 ； 水平異質 ； optimal trade policy ； Cournot competition ； horizontal differentiation

經濟論文叢刊

37卷2期（2009 / 06 / 01）

161 - 184

繁體中文

本文採用Hotelling的不完全覆蓋市場空間模型，假設產品的水平異質特性由廠商內生決定，建立一個三國二廠商的三階段貿易模型，探討廠商從事Cournot數量競爭下本國政府的最適單向出口政策。本文發現當產品的異質程度內生決定時，提高出口稅會創造一個水平異質效果，透過擴大產品之水平異質程度以降低競爭，進而提高價格與利潤水準，本國政府的最適單向出口政策爲課徵出口稅。其次，本文發現若二廠商均爲區域獨占廠商(local monopolist)，則最適政策爲自由貿易。再者，本文証明若短期內產品的異質程度來不及調整，則水平異質效果消失爲0，本國政府的最適單向出口政策仍爲出口補貼。最後，我們發現若外生的水平異質程度愈高，則本國政府會對廠商提供愈高的出口補貼率。

Using an uncovered market embedded in Hotelling's linear city model, this paper constructs a three-country, two-firm trade model with a three-stage game to explore the unilateral optimal export policy under Cournot competition, when the degree of horizontal differentiation is endogenously determined. The paper shows that a rise in the export tax creates a horizontaldifferentiation effect to mitigate competition by enlarging the degree of horizontal differentiation. This leads to the result that the optimal export policy of the domestic country is to levy a tax. However the optimal policy is free trade if the two firms act as local monopolists. The optimal policy is to subsidize, if the degree of horizontal differentiation remains unchanged in the short run. Lastly, the paper shows that a rise in the degree of horizontal differentiation raises the optimal rate of subsidy.

1. 楊雅博、吳世傑、黃鴻(2002)。規模報酬與最適貿易政策。經濟論文，30(1)，1-27。
   連結：
2. 楊雅博、黃鴻(2003)。同質Bertrand競爭下的最適貿易政策。經濟論文，31(1)，73-89。
   連結：
3. Anderson, S. P.,De Palma, A.(1988).Spatial price discrimination with heterogeneous products.Review of Economic Studies,55,573-592.
4. Anderson, S. P.,Neven, D. J.(1991).Cournot competition yields spatial agglomeration.International Economic Review,32,793-808.
5. Bandyopadhyay, S.,Bandyopadhyay, S. C.,Park, E. S.(2000).Unionized Bertrand duopoly and strategic export policy.Review of International Economics,8,164-174.
6. Berry, S.,Waldfogel, J.(2003).Product quality and market size.NBER Working Paper Series, 9675.
7. Brander, J. A.,Spencer, B. J.(1985).Export subsidies and international market share rivalry.Journal of International Economics,18,83-100.
8. D''Aspremont, C.,Gabzewicz, J.,Thisse, J.-F.(1979).On Hotelling's stability in competition.Econometrica,47,1145-1150.
9. De Fraja, G.,Norman, G.(1993).Product differentiation, pricing policy and equilibrium.Journal of Regional Science,33,343-363.
10. De Meza, D.(1986).Export subsidies and high productivity: Cause or effect?.Canadian Journal of Economics,347-350.
11. De Palma, A.,Ginsburgh, V.,Papageorgiou, Y. Y.,Thisse, J.-F.(1985).The principle of minimum differentiation holds under sufficient heterogeneity.Econometrica,53,767-781.
12. Dixit, A. K.(1984).International trade policy for oligopolistic industries.Economic Journal,94,1-16.
13. Dixit, A. K.,Stiglitz, J.(1977).Monopolistic competition and optimum product diversity.American Economic Review,67,297-308.
14. Eaton, J.,Grossman, G. M.(1986).Optimal trade and industrial policy under oligopoly.Quarterly Journal of Economics,101,383-406.
15. Economides, N.(1984).The principle of minimum differentiation revisited.European Economic Review,24,345-368.
16. Ferreira, R. D. S.,Thisse, J.-F.(1996).Horizontal and vertical differentiation: The Launhardt model.International Journal of Industrial Organization,14,485-506.
17. Hamilton, J. H.,Thisse, J. F.,Weskamp, A.(1989).Spatial discrimination: Bertrand vs. Cournot in a model of location choice.Regional Science and Urban Economics,19,87-102.
18. Hotelling, H.(1929).Stability in competition.Economic Journal,39,41-57.
19. Ishikawa, J.,Spencer, B. J.(1999).Rent-shifting export subsidies with an imported intermediate product.Journal of International Economics,48,199-232.
20. Klette, T. J.(1994).Strategic trade policy for exporting industries: More general results in the oligopolistic case.Oxford Economic Papers,46,296-310.
21. Lederer, P. J.,Hurter, A. P.(1986).Competition of firms: Discriminatory pricing and location.Econometrica,54,623-640.
22. Liang, W. J.,Hwang, H.,Mai, C. C.(2006).Spatial discrimination: Bertrand vs. Cournot with asymmetric demands.Regional Science and Urban Economics,36,790-802.
23. Maggi, G.(1996).Strategic trade policies with endogenous mode of competition.American Economic Review,86,237-258.
24. Mai, C. C.,Hwang, H.(1988).Optimal export subsidies and marginal cost differentials.Economics Letters,27,279-282.
25. Neary, J. P.(1994).Cost asymmetries in international subsidy games: Should governments help winners or losers?.Journal of International Economics,37,197-218.
26. Qiu, L. D.(1994).Optimal strategic trade policy under asymmetric information.Journal of International Economics,36,333-354.
27. Shimizu, D.(2002).Product differentiation in spatial Cournot markets.Economics Letters,76,317-322.
28. Singh, N.,Vives, X.(1984).Price and quantity competition in a differentiated duopoly.Rand Journal of Economics,15,546-554.
29. Spence, A. M.(1976).Product selection, fixed costs and monopolistic competition.Review of Economic Studies,43,217-236.
30. Spencer, B. J.,Jones, R. W.(1991).Vertical foreclosure and international trade policy.Review of Economic Studies,58,153-170.
31. Yang, B. S.,Liang, W. J.,Hwang, H.,Mai, C. C.(2007).A general analysis of spatial cournot competition in a linear city model.Working Paper.
32. Zhou, D.,Spencer, B. J.,Vertinsky, I.(2002).Strategic trade policy with endogenous choice of quality and asymmetric costs.Journal of International Economics,56,205-232.
33. 林燕淑、黃鴻(1998)。最適出口補貼與空間競爭策略性貿易政策。經濟論文，26(1)，1-18。