ABSTRACT We investigate if the existence of low-quality audits in an auditor office indicates the presence of a “contagion effect” on the quality of other (concurrent) audits conducted by the office. A low-quality audit is defined as the presence of one or more clients with overstated earnings that were subsequently corrected by a downward restatement. We document that the quality of audited earnings (abnormal accruals) is lower for clients in these office-years (when the misreporting occurred) compared to a control sample of office-years with no restatements. This effect lasts for up to five subsequent years, indicating that audit firms do not immediately rectify the problems that caused contagion. We also find that an office-year with client misreporting is likely to have subsequent (new) client restatements over the next five fiscal years. Overall, the evidence suggests that certain auditor offices have systematic audit-quality problems and that these problems persist over time. Data Availability: All data are publicly available.

Audit regulators around the world have expressed concern over market dominance by Big 4 accounting firms and the potential adverse effect it may have on the quality of audited financial statements. We use cross‐country variation in the audit market structure of 42 countries to examine two separate aspects of Big 4 dominance: (1) Big 4 market concentration as a group relative to non–Big 4 auditors; and (2) concentration within the Big 4 group in which one or more of the Big 4 firms is dominant relative to the other Big 4 firms. We find that in countries where the Big 4 (as a group) conduct more listed company audits, both Big 4 and non–Big 4 clients have higher quality audited earnings compared to clients in countries with smaller Big 4 market shares. In contrast, in countries where there is a greater concentration within the Big 4 group, we find that Big 4 clients have lower quality audited earnings compared to countries with more evenly distributed market shares among the Big 4. Thus concentration within the Big 4 group appears to be detrimental to audit quality in a country and of legitimate concern to regulators and policymakers. However, Big 4 dominance per se does not appear to harm audit quality and is in fact associated with higher earnings quality, after controlling for other country characteristics that potentially affect earnings quality.

Francis and Yu (2009) and Choi, Kim, Kim, and Zang (2010) report evidence that Big 4 audits are of higher quality when the engagement office is of larger size. Specifically, client earnings quality is higher and auditors in larger offices are more likely to issue going‐concern audit reports. We extend this line of research to test if larger Big 4 offices have fewer client restatements. A client restatement provides more direct evidence of a low‐quality audit than earnings quality metrics or going‐concern reports, because a restatement indicates the client's auditor did not effectively enforce the correct application of GAAP at the time the original financial statements were issued. We analyze 2,557 firm‐year restatements in a sample of 23,190 financial statements originally issued by U.S. firms from 2003 to 2008. We find that Big 4 office size is associated with fewer client restatements after controlling for innate client characteristics that may affect restatements (client size, financial performance, industry membership, nonfinancial measures, off‐balance sheet activities, and market‐related measures), and a set of controls for other auditor factors such as fees and industry expertise. The study raises important questions about the ability of smaller offices to deliver high‐quality audits for SEC registrants.