ST-announced Market Reaction Research Based On Investor Behavior Bias Theory

There are some irrational investment phenomena in the ST stock plate for a long time.The long-term existence of this phenomenon is not conducive to t he development of the stock market in China.This paper analyzes the impact of ST announcements influence on stock prices from the perspective of investo rs' behavioral bias and some irrational behaviors in ST stock market.We make analysis and hypothesis based on the assumption of heterogeneous investors to fill the blank of research on investor behavior bias in ST stock plate.This article uses the event analysis method as the main research method and puts forward the hypothesis based on the investor behavior deviation theory and carries on the empirical analysis.The conclusions are as follows: 1.The abnormal fluctuation of the stock price before the announcement day is the essence of the lack of market reaction.2.After the implementation / revocation of the ST bulletin,the market will be overreactive.3,mental accounting theory can be used to explain the reasons why people respond differently to ST announcements for different reasons.An empirical study on the "anomalies" reflect irrational investment behavior in China's stock market.Conservative bias,overreaction,underreaction phenomenon reflect that the market needs to improve the ability of allocation resources.All the phenomena reflect China's stock market is not in the semi strong efficiency.