中文摘要：

本文从动态竞争视角探索股权制衡对企业绩效的作用路径，在模型中加入企业防御能力变量，以解释股权制衡对企业绩效的影响机理。利用231家高科技民营上市公司20082012年的面板数据，本文对股权制衡、企业防御能力与绩效间的关系进行实证分析，得出如下结论：股权制衡有利于提升企业在动态竞争中的防御能力；股权制衡度对企业绩效存在正向影响；股权制衡度对企业绩效的正向影响是通过提高企业防御能力实现的。本文同时探讨了企业经营风险倾向在防御能力与企业绩效关系中的调节作用，结果表明：企业风险倾向越高，防御能力对企业绩效的促进作用越强。

英文摘要：

This paper explores the role of equity balance in firm performance from a perspective of dynamic competition, and introduces corporate defense capability into the model to explain the effect of equity balance on firm performance. Based on the panel data of 231 high-tech private listed companies from 2008 to 2012, this paper makes empirical analysis of the relationship between equity balance, corporate defense capability and firm performance, and draws the following conclusions.firstly, equity balance helps to enhance corporate defense capability in dynamic competition; secondly, equity balance has a positive impact on firm performance~ thirdly, the positive effect of equity balance on firm performance is realized through the enhancement of corporate defense capability. Meanwhile, it discusses the moderating role of operating risk propensity in the relationship between defense capability and firm performance and shows that higher risk propensity results in stronger promotion effect of defense capability on firm performance.