中文摘要
利用极为独特详尽的数据, 我记录了一个现象: 在同一航线上、同一集装箱内运输的同类产品, 其不同批次货运之间的运价存在巨大差异。我运用一个纳入规模经济与运输环节价格歧视的贸易模型来解释这种差异, 并推导出每种机制各自不同的政策含义。为了区分这两种机制, 我检验了竞争对运价差异的影响——这一影响为价格歧视机制所特有。我以未曾预料到的水位变化作为河运竞争的工具变量, 发现竞争加剧使较大批量的货运获得幅度更陡的折扣。因此, 运价差异可由运输公司的市场势力来解释, 且其扭曲性对规模较大的企业较小——这些企业由此获得额外的成本优势。
Abstract
Using uniquely detailed data, I document large freight price variation across shipments of similar products transported within the same container on the same route. I rationalize this variation using a trade model that incorporates economies of scale and price discrimination in transportation. I derive each mechanism’s distinct policy implications. To distinguish them, I test for the effect of competition on freight price variation specific to price discrimination. Using unexpected water level changes as an instrument for competition in river transportation, I find increased competition causes steeper discounts for larger shipments. Thus, freight price variation is explained by market power of transport companies and is less distortionary for larger firms, who gain additional cost advantages.