1989 / November

寡佔市場之最適進口配額政策：貿易自由化之福利效果
Optimal Quota Policies in an Oligopolistic Market : The Welfare Effects of Trade Liberalization

研究論文 Research Article

麥朝成, 黃鴻
Chao-cheng Mai, Hong Hwang

1-13

在這篇論文中，我們利用一個非常簡單的寡佔模型分析長期與短期的最適進口配額水準。我們發現在短期不論是市場自由化（卽廠商家數增加）或者貿易自由化（卽進口配額提高）其對個別廠商產量之影響都不確定，端視需求曲線的曲度而定。只要市場需求曲線不是十分 convex，此二自由化措施均會導至個別廠商產量增加，市場價格下跌。在長期，貿易自由化則不會改變產品之總產量與價格。此外，一般而言，長期最適配額水準大於短期最適配額水準。

In this paper, we employ a simple oligopolistic model to examine optimal import quota levels in both the short and the long runs. It is found that the output effects of market liberalization (i.e., an increase in the number of firms or trade liberalization as measured by a rise in quota levels) are ambiguous in the short run as they depend on the convexity of the demand curve. The market price would fall and industry output rise if the demand curve is not sufficiently convex. In contrast, liberalization has no effect on market output and price in the long run. It is also concluded that the long run optimal quota, in general, is greater than the short run one.

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