密度经济与自然垄断

经济学对自然垄断成因的解释有“规模经济”和“成本劣加性”等学说。对于现代自然垄断集中于网络型产业,近年来学者们都以“网络经济”说予以解释,并提出了规模经济、范围经济和网络经济结合的所谓“三位一体”的自然垄断理论。本文以城市自来水行业为例,对网络型产业各环节的成本特性进行具体分析,揭示现代自然垄断收敛于网络型产业是因为网络系统所特有的“密度经济”效应,为现代自然垄断现象提供了一种全新的、更具一般意义的理论解释。

Economy of Density and Natural Monopoly

The natural monopoly has traditionally been attributed to the economy of scale and sub-addivity of cost.Recently it is attributed to the economy of network by some economists,for the natural monopoly has already been concentrated to industries with networks.This paper takes the urban water supply system as an example to analyze the nature of the cost of industries with networks,and to show that natural monopoly is actually due to the economy of density instead of the traditional causes.This conclusion has offered a completely different explanation to the modern phenomena of natural monopoly.