上市公司公告时间的选择对公告信息含量的影响——基于2001-2007年沪市上市公司年报公告的事件研究

The Influence of Announcement Time Choice by Listed Company on Information Content——Event Study on Listed Company Annual in Shanghai Stock Exchange from 2001-2007

本文以2001—2007年沪市A股上市公司的年报公告为研究对象,对年报公告的时间选择进行研究。研究发现,一定情况下,上市公司的公告时间选择行为是会改变公告的信息含量的,公司可以通过这一行为控制公司盈余的市场反应。当上市公司盈利水平提高(未预期盈余为正)时,这种调控行为的市场反应并不明显;而当上市公司盈利水平降低(未预期盈余为负)时,这种调控行为的市场反应趋于明显。并且,在1、2月份阶段公告年报,上市公司越提前公告越能弱化市场对利空消息的不利反应;而在3、4月份阶段公告年报,上市公司越延后公告越能弱化市场对利空消息的不利反应。

With the annual announcements of A-shares in Shanghai Security Exchange between 2001--2007, we investigate that A-shares can change their announcements＇ informativeness and affect the reflection of market by the choice on announcements disclosure＇ timenliness. When listed companies＇unexpected earnings are negtive, the influence is obvious. But it＇ s not true when unexpected earnings are postive. When listed companies＇ annual announcements are disclosed in January or February, earlier the announcements are disclosed, weaker the market reactions are. But it＇s not true when announcements are disclosed in March or April.