中文摘要：

借助于微博这一新型传媒，上市公司的信息披露由“公告独自”向“多渠道对话”转变，有利于提高上市公司信息披露的广度。通过手工收集在新浪微博开设官方微博的上市公司微博信息，从股价同步性的视角对上市公司微博信息披露的有用性进行了研究。研究结果表明，上市公司官方微博披露的数量与股价同步性显著负相关，而这种负相关关系主要体现为微博披露的公司特质信息。进一步研究发现，微博信息披露与公司股价同步性之间的负相关主要表现在机构投资者持股比例较低组别以及信息透明度较高组别上，这表明微博的信息披露作用主要集中于机构投资者持股比例较低的上市公司，微博的信息披露作用取决于上市公司的信息透明度。

英文摘要：

With the help of Weibo, a new type of mass media, the information disclosure of the listed companies has been changed from ＂ announcement monologue＂ to ＂ multi-channel communication＂, which is helpful to improve the popularity of the information disclosure of the listed companies. By hand collecting the Weibo information disclosed by the listed companies which have official Weibo on Sina Microblog, this paper studies the usefulness of Weibo information disclosure of the listed companies from the perspective of stock price synchronicity. The results indicate that the information quantity disclosed by listed companies on their Weibos is significantly and negatively correlated to stock price synchronicity, and this kind of negative correlation is mainly in the corporate specific information disclosed on the Weibos. The results of further study show that the negative relationship between Weibo information disclosure and corporate stock price synchronicity is mainly reflected in the groups with lower proportion of institutional shareholding and in the groups with higher information transparency, which suggests that the effect of Weibo information disclosure is mainly focused on the listed companies with lower proportion of institutional shareholding and is depending on their information transparency.