新股发行超额收益率表现为:一个投资者以发行价买入新股,在上市第一天收盘时卖出股票所得的收益远远超过大盘整体收益率。对于IPO折价现象,财务经济学界研究的理论和基本点都在于信息不对称所产生的道德风险与逆向选择。根据投资者、承销商、发行公司之间的关系不同,国际上形成了各种不同的理论体系。 The issue of excess return on new shares is as follows: An investor buys new shares at the issue price. The proceeds from the sale of shares at the close of the first day of listing far exceed the overall yield of the broader market. For the phenomenon of IPO discount, the theoretical and basic points of research in the field of financial economics lie in the moral hazard and adverse selection caused by information asymmetry. According to the different relations among investors, underwriters and distribution companies, various different theoretical systems have been formed in the world.