2011年,68家境内外同时上市公司和214家A股自愿试点上市公司按规定实施了内部控制体系,其中68家境内外同时上市公司被强制要求出具内部控制审计报告。利用事件研究法发现:强制披露内部控制审计报告公司和自愿披露内部控制审计报告公司的累计超额收益率存在显著差异,进一步通过回归分析发现,内部控制审计报告不具有信息含量。 In 2011, 68 domestic and overseas concurrently listed companies and 214 voluntary A-share listed companies of the A-Share market implemented the system of internal control as required. Among them, 68 domestic and overseas concurrent listed companies were required to issue audit reports on internal control. Using the case study, it was found that there was a significant difference in the cumulative excess rate of return on the compulsory disclosure of the internal control audit report company and the voluntary disclosure of the audit report on internal control. Further regression analysis revealed that the internal control audit report does not have the information content.