国内外众多研究发现,公司发布定向增发公告往往会产生正的财富效应。如Wruck(1989)研究发现定向增发宣告期的平均超额收益率为4.5%;Hertzel和Smith(1993)发现定向增发宣告日前三天至宣告日的超额收益率为1.72%。章卫东(2007)以2005年5月至2007年3月发布定向增发预案的231家上市公司为样本,研究发现我国上市公司定向增发公告同样存在正的宣告效 Many studies at home and abroad have found that companies issuing directional private placement tend to produce positive wealth effects. For example, Wruck (1989) found that the average rate of return over the private placement period was 4.5%. Hertzel and Smith (1993) found that the excess return rate from the three days prior to the announcement to the announcement date was 1.72%. Zhang Weidong (2007), from May 2005 to March 2007, plans to issue 231 additional listed companies as a sample, the study found that China’s public placement of private placement also has a positive declaration of effectiveness