中文摘要：

本文以2006-2010年问沪深两市A股主板非金融公司为样本，研究了上市公司自愿披露内部控制审计报告对盈余质量和权益资本成本的影响。首先笔者通过倾向评分匹配法为在样本期间内自愿连续披露内部控制审计报告的公司（披露公司）匹配了一组在公司特征上相似的、但在样本期间内没有披露内部控制审计报告的公司（非披露公司），然后采用双重差分法比较分析了披露公司和非披露公司在盈余质量和权益资本成本上的差异。笔者发现，自愿披露内部控制审计报告的上市公司盈余质量高，权益资本成本低。倾向评分匹配法和双重差分法相结合的分析方法较好地解决了样本选择偏差和内生性问题。本文的研究发现为中国资本市场监管机构从2011年起逐步推行强制披露内部控制信息政策提供了经验证据，同时为公司管理层进行内控信息披露决策提供支持依据。

英文摘要：

Based on the non-financial firms listed on the Shanghai and Shenzhen stock exchanges during 2006-2010, this paper explores the economic consequences of voluntary disclosure of auditors＇ reports on internal control. With propensity score matching, firms that disclosed their auditors＇ reports on internal control continuously during 2006-2010 （disclosure firms） are matched with control firms that did not disclose any auditors＇ reports on internal control （non-disclosure firms）. Using the difference-in-difference approach, this paper compares firms＇ earning quality and cost of equity capital between the two groups. This paper finds that disclosure firms have higher earnings quality and lower cost of equity capital. These findings provide empirical evidence for the mandatory disclosure policy on auditors＇ reports on internal con- trol that was gradually implemented from 2011.