Abstract: The relationship between the synchronous volatility of stock price and the information content is controversial. This paper takes A-share listed companies with private placement in 2006-2014 as samples, and takes degree of discount of private placement as asymmetric information measure to study the relationship between the same fluctuation of stock price and the degree of information asymmetry, finding negative correlation exists between private placement underpricing and stock price synchronicity, which shows that stock price synchronicity in China has information content. Further analysis shows that analysts can reduce the degree of information asymmetry and reduce the impact of stock price synchronicity on private placement underpricing; the influence of the object of private placement to the relationship of private placement discount and stock price synchronicity is limited.

Key words: stock price synchronicity, private placement underpricing, information asymmetry