今回は、Posted: 30 May 2025に掲載されたマテリアルな欠陥開示の（非）物質性についての研究: 完全な解説の論文を分かりやすく解説・要約しました。
元の論文は下記の通りです。
The (Im)Materiality of Material Weakness Disclosures
出典元：SSRN
それでは早速見ていきましょう。
The Impact of Material Weakness Disclosures on Market Reactions and Investor Perceptions
Authors:
– Millie M. Hutton (University of Mississippi)
– Quinn T. Swanquist (University of Alabama)
– Robert L. Whited (North Carolina State University)
Introduction
The regulatory landscape of internal control reporting, particularly under the Sarbanes-Oxley Act (SOX), has emphasized the importance of material weakness (MW) disclosures for investors, issuers, auditors, and regulators. However, recent research challenges the prevailing belief that MW disclosures provide significant value-relevant information to investors. This study aims to delve deeper into the market reactions and investor perceptions surrounding MW disclosures to assess their actual impact.
Market Reactions to MW Disclosures
Analyzing the market reactions to MW disclosures reveals that there is limited evidence of a substantial negative reaction from investors. While early studies hinted at negative stock price responses to MW disclosures, the negative reactions appear to be confined to specific periods and lack consistency in recent years. Various market responses, including abnormal trading volume, abnormal returns, and earnings informativeness, are explored to gauge the information content of MW disclosures.
Investor Reactions and Abnormal Trading Volume
The study investigates abnormal trading volume as a measure of investor reactions to MW disclosures. Firms disclosing MWs experience higher trading volume compared to those with effective controls, indicating potential investor interest and disagreement. Although there is no significant price response to MW disclosures, the heightened trading volume suggests increased investor activity, possibly reflecting information content or valuation disagreement.
Earnings Informativeness and MW Disclosures
Examining how MW disclosures influence investors’ perceptions of earnings reliability, the study compares earnings response coefficients (ERCs) for firms with MWs to those with effective controls. While there is some weak evidence of lower ERCs for MW firms, the difference is not statistically significant after accounting for confounding factors. This raises doubts about whether investors rely on MW disclosures to interpret future firm disclosures.
MWs as Leading Indicators of Future Returns
Exploring whether MW disclosures signal future returns, the study finds that firms disclosing MWs experience significantly negative abnormal buy and hold returns in the months following the disclosure. This suggests that MWs may serve as a leading indicator of future stock returns, despite the lack of an immediate price reaction.
Additional Analysis and Placebo Tests
The study conducts additional analyses, including placebo tests, to discern whether market reactions are solely driven by MW disclosures. Results indicate that the observed patterns for MW firms may be influenced by other firm-specific traits rather than the MW itself. These findings underscore the need to consider firm-specific factors when interpreting market reactions to MW disclosures.
Conclusions
In conclusion, the study challenges the notion that MW disclosures significantly impact market reactions and investor perceptions. The limited evidence of a substantial negative market reaction to MW disclosures indicates that MWs may not elicit strong negative responses from investors. These findings contribute to the ongoing debate on the costs and benefits of internal control effectiveness disclosures mandated by SOX and emphasize the importance of considering firm-specific factors in understanding market reactions to MW disclosures. Further research is warranted to explore the evolving landscape of internal control practices and their implications for stakeholders in the accounting industry.
