Prior research on the impact of the Sarbanes-Oxley Act (SOX) (U.S. Congress [2002]) focuses primarily on the cost of its internal control reporting and audit requirements. In this study, we explore the relation betweeninternalcontrolqualityandidiosyncraticandsystematicrisk,andthe potential benefits of effective internal control in terms of cost of equity. Specifically, we investigate whether firms that disclose internal control deficiencies(ICDs)exhibithighersystematicrisk,higheridiosyncraticrisk,and higher cost of equity relative to firms with effective internal controls. Further, we investigate whether managements’ initial disclosures of ICDs and remediation of previously reported ICDs are related to changes in firms’ cost of equity.