An Empirical Study On The Effect Of Market Bulletin 's Surplus Announcement

GEM (Growth Enterprises Market) board opened in October2009, the number of listed companies has quickly increased to355. The listed companies in GEM board generally are high growth, innovative companies, investors are interested in the stocks of GEM board and at the same time they also bear a high risk of business and investment uncertainty, theshare price fluctuations of listed companies in GEM are often larger thanshares of motherboard market and Small and medium-sized plate market, there are also a variety of issues in GEM board which has established for3years:accounting information disclosure is not sufficient and timely, Phenomenon of one stock dominance is serious,mechanism of corporate governance and internal control is not perfect. The above mentioned problems will cause many more serious problems such as insider trading and opaque information and news leaks, which lead to the losses of investors. Especially for China’s capital market trading conditions, problems of operating share price and speculationare more serious, at the same time GEM listed companies generally are smaller scale and higher growth companies, corporate performance is easily changed, stock price is easily operated because of small plate characteristic, greater stock price volatility may be difficult to avoid. It is important for investors to understand the earnings informationin the performance report of the companies listed on GEM.Investors make a large part of the investment decision-making relying on the interpretation of the performance report containing earnings information disclosed. In this paper, we selected254pre-announce performance reports of listed companies on the Growth Enterprise Market (GEM) in2012and divide them into two groups:the good news group and the bad news group.we selected the return on equity (ROE) as a measure of earnings information, using the traditional event study methodology to set the window period around the announcement of the results of performance and measure the relative trading volume, stock price abnormal gains rate, the average cumulative abnormal returns. Our study found that The earnings information obviously affected the fluctuations of shares price of companies listed on GEM, there are also serious problems of leaking ofinsider information and insider trading, moreover we found owing the good news group in the event window will lead to losses because of negative cumulative average excess return rate, but owing the bad news group will bring the positive cumulative average excess yield, and we also found a interesting phenomenon,that is, the bad news group show U-fluctuation trend.