The Sarbanes-Oxley Act (S-O Act) of 2002 requires principal officers to certify under oath to the veracity of information contained in SEC filings and opine on the effectiveness of the internal control system. This study examines the determinants and contents of corporate voluntary disclosure of management\u27s responsibilities during the five-year period preceding the S-O Act. We predict that the voluntary disclosure of management\u27s responsibilities for financial information signals certain incentives and characteristics of the reporting firm that are relevant to financial statement users and regulators. Consistent with our predictions, our findings reveal significant differences between issuing and non-issuing firms as to the effectiveness of an individual firm\u27s internal control system, access to capital markets, audit committee characteristics, and ownership structure. An empirical analysis of the contents of these assertions also reveals different areas of emphasis and selectivity by management, which represents an informative link to existing disclosure mandates. The results of this study contribute to our knowledge of management\u27s motivations for voluntary disclosure and lend credence to the mandatory certification requirements and related disclosure reforms established in the post-Enron era
