Academic studies concerning pricing efficiency of stock market mainly focus on whether the stock market is an efficiency market and the market form, but do not give quantitative indexes to measure pricing efficiency. In this article, we employed a state-of-art Spring Oscillator Theory to study pricing efficiency of the Shanghai Securities Exchange and especially, the quantitative analysis of stock price response to public information. We chose 50 typical listed stocks in the Shanghai Securities Exchange in our sample, and use annual report release to represent events that affect stock price. We made an empirical study on the relationship of pricing efficiency varies with time and correlation with the circulation size. Empirical results demonstrated that pricing efficiency went through a gradual declining during 2011-2013, and compared with 2009, the pricing efficiency of the stock market has been improved significantly in 2013. Additionally, no significant relations of stock pricing efficiency and its circulation size exist according to our empirical study.
