中文摘要：

以2006年年报公布后至2007年4月24日上海证券交易所61家上市公司发布的第一季度和中期业绩预增公告为样本，对股权分置改革以后的业绩预增公告进行了信息含量的实证分析。结果表明，在股权分置改革后，业绩预增公告确实具有非常强的信息内涵，但是市场对此公告存在一定程度的信息提前反应，市场对业绩预告的监督作用仍然比较弱，业绩预告制度有待进一步完善。

英文摘要：

This paper does an empirical study on the information content after the equity splitting reform. The sample is the performance growing forecast of the first quarter and the medium - term for 61 listed companies in Shanghai Stock Exchange and the time of announce is between the publication of the annual report of 2006 to April 24, 2007. Results show that performance growing forecasts have strong information content after the equity splitting reform, but market exists a certain degree of earlier reaction phenomenon for performance growing forecasts and the market of the supervisory role is still relatively weak, so our system of performance forecast still subjects to further refinement.