贸易壁垒对产业链下游寡头市场均衡的影响——以大豆产业链为例  

The Impact of Trade Barriers on the Equilibrium of the Oligopolistic Market Downstream of the Industrial Chain:Taking the Soybean Industrial Chain as an Example

作　　者：张瀚元 殷晓鹏[1] Zhang Hanyuan;Yin Xiaopeng

机构地区：[1]对外经济贸易大学国际经济贸易学院

出　　处：《宏观经济研究》2020年第10期42-57,125,共17页Macroeconomics

摘　　要：中国曾经是大豆生产大国,不仅能满足国内需求,还有大量出口。但是自上世纪90年代末以来国产大豆逐渐不能满足国内市场的需求,进口大豆在几年间迅速占领了市场,尤其在加入世贸组织后,随着大豆进口关税的大幅削减,美国对中国的大豆出口逐年猛增,价格也低于国产大豆,国内大豆减产。本文以大豆产业链为例,建立互惠贸易模型,研究寡头垄断市场结构下大豆产业链中上下游企业的数量竞争均衡,并分析上游市场的贸易壁垒,主要是进口关税和出口补贴对上下游企业的产量、价格、利润、消费者福利以及社会总福利水平的影响。研究发现在如果只考虑食用大豆市场的局部均衡,征收关税会导致寡头均衡时进口大豆的价格低于国产大豆的价格,而不是像完全竞争市场上因为征收关税而导致价格升高。征收关税反而会增加社会总福利水平,而对国外厂商的补贴则会减少社会总福利。在大豆产业链中,大豆市场与豆油市场完全联系在一起,豆油市场的均衡决定了对榨油用大豆的需求。在上下游市场都达到寡头均衡时,与自由贸易时相比,对上游产品征收进口关税会降低下游厂商的利润,降低社会总福利水平。China used to be a large soybean producer,not only meeting domestic demand,but also exporting a lot.However,since the late 1990 s,domestic soybeans have gradually failed to meet the domestic market demand.Imported soybeans quickly occupied the market within a few years,especially after joining the WTO.With the substantial reduction of soybean import tariffs,the US soybean exports to China soaring year by year,the price is also lower than domestic soybeans,and domestic soybean production is reduced.This paper takes the soybean industry chain as an example,establishes a reciprocal trade model,studies the quantity competition equilibrium of upstream and downstream enterprises in the soybean industry chain under the oligopoly market structure,and analyzes the trade barriers in the upstream market,mainly the impact of import tariffs and export subsidies on the output,prices,profits,consumer welfare,and total social welfare of upstream and downstream enterprises.The study finds that if only the local equilibrium of the edible soybean market is considered,the imposition of tariffs will cause the price of imported soybeans to be lower than the price of domestic soybeans in the oligopoly equilibrium,rather than the rise in prices due to imposition of tariffs in a perfectly competitive market.On the contrary,imposing tariffs will increase the level of total social welfare,while subsidies to foreign manufacturers will reduce total social welfare.In the soybean industry chain,the soybean market and the soybean oil market are completely linked,and the equilibrium of the soybean oil market determines the demand for soybeans for oil extraction.When both the upstream and downstream markets have reached an oligopoly equilibrium,compared with free trade,imposing import tariffs on upstream products will reduce the profits of downstream manufacturers and reduce the level of social welfare.

关 键 词：大豆 贸易壁垒 互惠市场模型 产业链 

分 类 号：F323.7[经济管理—产业经济] F752.6