多样化水平与中国企业出口波动:基于产品和市场组合的研究

Diversification and Volatility in the Chinese Firms’ Exports: A Study on Product Mix and Market Portfolio

借鉴Markowitz资产组合理论的思想,本文利用中国制造业企业2000—2012年的出口交易数据,检验了企业在产品和市场组合上的多样化水平对其出口波动的影响,并对三者之间的作用机制进行了探讨。研究发现,首先,中国企业多样化水平在经历了加入WTO的急速上升之后处于相对稳定的水平。但是,企业间的多样化水平在贸易方式、区域和产业等层面呈现出明显的分化特征。其次,出口多样化指数对企业出口波动的影响呈现"倒U型"的动态特征。从平抑出口波动的效果上来看,市场多样化要比产品多样化更为有效。本文还进一步通过分解出口方差、构建中介效应模型揭示了市场多样化策略影响企业出口波动的机制。

Taking stock of Markowitz's thinking on asset portfolio,this paper tests the impacts of export diversification in firms'product mix and market portfolio on its volatility by means of the 2000-2012 export data of Chinese manufacturing firms.It is found that :(1)the level of export diversification experienced a sharp increase after the China's accession to WTO in 2001 and stays at a relatively stable level,but the diversification among the firms shows high heterogeneity in term of trade pattern,region and industry;(2)the impact of export diversification index on export volatility takes on an inverted U shape.In view of the effects of keeping down the export volatility,the diversification in market portfolio plays a bigger role than the product mix does;(3)furthermore,by decomposing the export variance,this paper builds up a model of mesomeric effects to disclose the mechanism of the market portfolio ploys affecting the firms'export volatility.