中文摘要：

基于“产品市场竞争——风险预期——权益资本成本”的关联视角，分析了产品市场竞争的公司治理效应和特质性风险效应，并以我国A股上市公司2004～2011年的平衡面板数据为样本进行了实证检验。研究结果显示，集中的行业结构和强大的市场势力降低了特质性风险，进而降低了投资者的风险预期和权益资本成本，即产品市场竞争的特质性风险效应显著；在政府干预少和法治水平高的地区，产品市场竞争的特质性风险效应趋于减弱。

英文摘要：

Using a total of 2552 firm-year balanced panel data of A-share listed companies in the 2004 to 2011 period and based on the related respective of competition, expected risk and cost of equity capital, this paper empirically analyzes the function of product market competition on cost of equity capital and institutional environments＇ regulatory influence from product market competi- tion＇s effect of corporation governance and idiosyncratic risk. The empirical results show that the more concentrated industry and stronger product market power can reduce the idiosyncratic risk, cut down expected risk and cost of equity capital, that is, product market competition＇s idiosyncratic risk effect is more significant; product market competition＇s idiosyncratic risk effect tends to be weaker in the region where government intervention is little and law enforcement is better.