考虑港口收费管制的进出口贸易竞争研究

考虑港口的收费管制因素，建立了进出口贸易竞争模型。该模型由一个出口国和两个进口国组成，且各国都拥有一个港口，位于出口国的两家公司均向两个进口国销售商品，并在各个进口国展开市场竞争（古诺竞争或伯川德竞争），各贸易国的港口根据其是否存在价格管制确定港口收费。针对进出口公司的每种竞争模式，得到了不同的港口收费管制组合下各贸易国的港口收费、港口利润和社会福利，并将竞争均衡结果进行了比较。研究发现： （1）在进出口公司古诺竞争模式下，若三个贸易国的港口都无收费管制（有收费管制）且进出口产品的差异较大 （小）时，各贸易国的社会福利和港口利润均更高； （2）在进出口公司伯川德竞争模式下，若进出口产品的差异较大 （小），则出口国的港口利润主要取决于港口收费 （贸易量），而进口国恰好相反； （3）当进出口产品的差异较大 （小）时，进出口公司在古诺 （伯川德）竞争模式下各贸易国的社会福利、港口利润以及港口使用费都更高。

Research on the Import and Export Trade Competition Considering the Port Pricing Regulation

The port pricing regulation factor is considered in the competition model of import and export trade, which consists of one exporting country and two importing countries, with each country having one port. Both companies in the exporting countries sell goods to two importing countries and compete in the market of each importing country (Cournot competition or Bertrand competition). Port charges are determined according to whether there is a price control policy in the port of each trading country. With each competition mode of import and export companies, port charges, port profits and social welfare of each trading country under different combinations of port pricing regulation policy are obtained, and then the results of competition equilibrium are compared. It is found that: (1) if there is no pricing regulation (with pricing regulation) in the ports of the three trading countries and the difference of import and export products is large (small) under Cournot competition, the social welfare and port profits of each trading country are higher; (2) if the difference of the import and export products is large (small), the port profit of the exporting country is mainly dependent on the port charge (trade volume) under Bertrand competition; (3) when the difference of import and export products is large (small), the social welfare, port profits and port charges in trading countries are higher under Cournot competition (Bertrand competition).