本文用实证方法对上市公司增发新股公告日前后的股票超额收益率进行了研究。研究表明在公告日前股 票的累计超额收益率就开始下跌，上市公司增发新股的市场认同度较小。 This paper studies the excess return rate of stocks before and after the announcement of the issuance of new shares of listed companies with the empirical method. Research shows that before the announcement day, the accumulated excess return rate of stocks began to drop, and the market recognition of new shares issuance by listed companies was relatively small.