Material Weakness
A deficiency in a company's internal controls over financial reporting significant enough that there is a reasonable possibility of a material misstatement going undetected.
What is Material Weakness?
A material weakness is a deficiency — or combination of deficiencies — in a company's internal controls over financial reporting (ICFR) such that there is a reasonable possibility that a material misstatement of the financial statements will not be prevented or detected in a timely manner. Under the Sarbanes-Oxley Act Section 404, management of public companies must annually assess the effectiveness of ICFR, and external auditors must independently attest to that assessment. Disclosure of a material weakness is a serious red flag: it indicates that reported financial data may be unreliable, increases the risk of restatements, and raises governance concerns. Common causes include: insufficient accounting staff, inadequate segregation of duties, lack of documentation for complex transactions, errors in financial close processes, and IT control failures. Investors and lenders often react negatively to material weakness disclosures, and the company is typically required to remediate the weakness and report on remediation progress in subsequent periods.
Example
In 2023, a regional bank disclosed a material weakness in its allowance for credit loss (ACL) calculation process — the model used to estimate loan losses contained manual errors not detected by existing review procedures. The bank's auditors identified this as a material weakness in a required Sarbanes-Oxley Section 404 assessment. The bank restated prior-period financial results, replaced its controller, implemented automated ACL controls, and disclosed remediation steps in its next quarterly report.
Source: PCAOB — AS 2201: Internal Control Over Financial Reporting