本文以2009-2014年IPO(initial public offerings)公司上市前信息市场为研究对象,研究了公司上市前一年媒体报道与IPO首日换手率之间的相关关系.结果发现媒体关注度会显著正向影响IPO首日换手率,但该状况仅在承销商声誉较低时适用,当承销商声誉较高时这种相关关系会被高声誉的承销商所释放的强信号所减弱.进一步地,文章依照2012-2013年的IPO停牌期间将样本划分为政策变动前和政策变动后两个子样本,发现政策变动后媒体情绪对IPO首日换手率的影响变得不显著,可能的原因是由于政策变动后媒体的信息传播效应被政策波动所掩盖.文章以一个清晰的信息市场作为样本选择来源以排除其他信息主体的干扰,证实了媒体在信息市场中的信息中介角色,但该角色需要在一定条件下才会显著发挥作用.
Using initial public offerings (IPO) company data between 2009 and 2014, we examine the relationship between media coverage and turnover on the first day of initial public offerings. The media attention is positively related with the turnover rate on the first day of IPO, which is examined when the reputation of the underwriter is low. The relation of media attention and IPO turnover is weakened by the strong signal effect of high-reputation underwriter. Furthermore, we divide the sample into two sub-samples by the policy changes, one with IPO companies before the policy change in 2013, the other with IPO companies after the policy change in 2013. It turns out that the effect of media sentiment on IPO turnover disappears after the policy change, which may be explained by the substitution between policy changing and information dissemination of media. Using an IPO sample to eliminate the other interferences, the paper verifies the infomediary role of media in information market, and detects the environment under which it works.