Abstract: Breaking the previous stereotyped thinking that the researches of the generation mechanism of herd behavior based on information mechanism should be limited to the information asymmetry theory, this paper turns its perspective to the logical relationship between the information competition of institutional investors and their herd behaviors, then it conducts an empirical test according to the detailed positioning data of the institutional investors from 2005 to 2017. The findings show that the competition for the information of private enterprises among institutional investors will lead to the emergence of their herd behaviors, especially for the herd behavior of the buyers; the impact of information competition on it is particularly significant. Further analysis of the nature of the herd behavior shows that the herd behavior of institutional investors caused by information competition in China’s A-share markets belongs to the pseudo-herd behavior of non-deliberate imitation. This consistent response based on homogenous information can help to perfect the stock price information transmission mechanism and can play a role in suppressing the phenomenon of stock price synchronization.

Key words: institutional investors; herd behavior; information competition; stock price synchronicity