中文摘要：

通过构建度量机构投资者持股持续期的指标,并按照持股持续期的长短将机构投资者分为长期和短期机构投资者,分析了机构投资者的持股持续期与公司业绩的关系。研究发现：股权分置改革后,机构投资者的持股持续期与公司业绩正相关;当机构投资者的持股比例较高时,持股持续期越长,其对公司业绩的改善就越明显;不同类型的机构投资者在改善公司业绩方面存在显著差异,长期机构投资者以及基金和QFII能够改善公司业绩,而短期投资者以及券商、信托公司和保险公司不能改善公司业绩。

英文摘要：

In this paper,we construct the index to measure the continued duration of investors＇ stock ownership. Based on the index,long-term and short-term institutional investors are separated. We document a positive relationship between firm performance and continued duration of institutional investors＇ stock ownership after the ownership-split reform. When the proportion of institutional ownership is high,the longer the continued duration of investors＇ stock ownership is,the better the firm performance will be. Different types of institutional investors have different effects on the firm performance：long-term institutional investors can improve the company＇s performance,while the short-term institutional investors cannot do so,and the fund and QFII investors can improve the firm performance,while the security dealers,trust companies and insurance companies cannot improve the firm performance.