Abnormal Fluctuations Of The Stock Transactions Of Listed Companies In China

The stock trading abnormal fluctuation is a big headache of the stock market supervisor. In 2007, the China stock market was a bully market after the reform of non-tradable shares almost completed. The listed companies' stock price abnormal fluctuation numbers increased significantly. The stock price abnormal fluctuation phenomena tied up with insider trading, illegal information announcement, and price manipulation. Many abnormal fluctuation phenomena occurs together with the rumors of private offering, asset reconstruction, "on listed as a whole" and "back-door listing". The abnormal stock prices up and down hurt the normal investor rights and interests, and also the healthy development of China capital market.The paper describes and analyses the abnormal fluctuation behaviors of China public company in 2007 from Wind database. By statistical analysis the published trading seats and carefully researching the relative information released, we would understand that institutional investor over-trading, the private larger trader manipulating activities and the over- speculation of the individual investors led to the stocks abnormal fluctuation. After the completion of the reform of non-tradable shares, "Good asset infusing" and "on listed as a whole" are the two main information resources of abnormal fluctuation. "Security agent back-door listing", "public company with large stock investment", "big orders/project obtain" are also the hot topic of abnormal fluctuation.It is also found that there obviously existed the information leakage since the abnormal fluctuation often happened several days or weeks before the listed company gave out the important information disclosure. Illegal information disclosure and insider trading still the big problem of our security market.This paper intends to provide the valuable suggestion and reference to the security supervisor in order to reinforce their supervisory measure of listed company information disclosure, to increase the efficiency of supervisory and to prompt the healthy and steady development.