中文摘要：

基于2008--2012年上市公司数据，利用门槛效应和无条件分位数模型，本文探讨了机构投资者持股与企业研发投入的非线性关系和机构投资者异质性。研究结果表明：（1）机构投资者持股比例需要跨过一定门槛，才会对企业研发投入起到促进作用；（2）基金公司、券商以及社保基金持股对不同分位点研发水平有不同程度地促进作用；（3）银行和财务公司持股对不同分位点研发水平有不同程度地抑制作用。

英文摘要：

Based on listed firm data from 2008 to 2012, this paper uses the threshold effect model and the unconditional quantile model to study the non-linear relationship between institutional investors and R＆D investment as well as the heterogeneity in such relationship. The resuhs show that ： （ 1 ） The share of institutional investment needs to reach a certain threshold to play a catalytic role in affecting corporate R＆D investment;（2） Shares held by mutual funds companies, brokerage firms and social security funds all have a varying degree of promoting effects on the quantile level of R＆D investment ; and, （ 3 ） Banks and finance company shares, on the other hand, have different degrees of inhibitive effects on the quantile levels of R＆D investment.