Using a proprietary data set consisting of all private firm audit engagements in 2000 from one Big 4 firm in Belgium, we investigate (i) whether audit office industry scale is associated with a reduction of total, partner, and staff audit hours and thus with efficiency gains triggered by organizational learning from servicing more clients in an industry and (ii) whether the extent of efficiency pass‐on from the auditor to its clients depends on the audit firm's market power. We find that auditor office industry scale is associated with efficiency gains and a reduction of the variable costs (i.e., fewer total audit hours, partner hours, and staff hours), ceteris paribus. Our results also suggest that, on average, realized efficiencies are entirely passed on, as evidenced by a nonsignificant effect of auditor industry scale on the auditor's billing rate. Furthermore, we find that the extent of the efficiency pass‐on decreases with the market power of the audit firm in the industry market segment as we document a higher billing rate for auditors with high market power (versus low market power). In addition, we find that the lower audit hours associated with auditor industry scale do not compromise audit quality.

We develop the concept of auditor industry range as the extent to which an auditor has experiences in auditing clients from different industries, and we link this construct to auditor performance, drawing on prior research in psychology and cognitive science. We find that auditors with a wide range of industry experiences are more likely to require audit adjustments than auditors with a narrow range. We conduct an extensive set of analyses to mitigate the concern that our results are driven by endogenous matching between auditors and clients. The positive relation between auditor industry range and audit adjustments exists regardless of whether the industries covered by an auditor's portfolio exhibit strong or weak economic co-movement, and the relation is stronger for more complex clients, in more uncertain environments, and for auditors with more years of audit experience. Overall, our findings suggest that an auditor's diverse experiences in different industries can enhance audit quality.

In contrast to prior research that typically focuses on the characteristics of the audit committee (AC), we investigate how intergroup differences between the AC and the rest of the board (ROB) affect monitoring effectiveness. Drawing on group literature and the similarity attraction paradigm, we hypothesize that high intergroup differences between the AC and the ROB impede communication and information sharing. Poor “fit” between the AC and the ROB can lead to an “us versus them” mentality that reduces trust and hinders knowledge exchange, diminishing monitoring effectiveness. Using a sample of listed US firms, we find that intergroup differences between the AC and the ROB in terms of their respective characteristics are linked to a lower likelihood of reporting an existing or likely material weakness, higher discretionary accruals, and a lower likelihood of a going‐concern opinion among financially distressed firms. These negative effects are most pronounced when the AC and the ROB are very different (i.e., in the upper quartile and decile of the AC‐ROB distance distribution). Additional analyses show a higher probability of a Big R restatement, a lower likelihood of a Big R restatement when a material misstatement likely exists, and a lower likelihood of goodwill impairment when one is expected. Notably, the adverse impact of AC‐ROB dissimilarity is more prominent when the AC is less powerful or lacks group stability. Regulators and companies should be aware that AC composition decisions cannot be made in isolation because large intergroup differences in director profiles between the AC and the ROB reduce monitoring effectiveness.

Competition in audit markets is an important topic but direct tests of market competition have been limited. In this paper, we examine how audit firms behave when they are confronted with competition from another firm in a wide range of industry segments in a local market. Sharing a large number of market segments can lead to mutual forbearance among audit rivals. Such mutual forbearance is likely to manifest as higher audit fees in a market because rivals are hesitant to aggressively compete in the face of potential competitive retaliation. Using a sample of 25,662 observations from 2004 to 2015, we find evidence that supports this argument as proxied by the extent that audit firms compete in the same industries in the same locations. This result persists after controlling for several tight fixed‐effects specifications based on time, location, industry, and market segments. In supplementary tests, we also find that the likelihood of client switching is negatively associated with the multi‐industry contact of the incumbent, but clients that do switch are more likely to choose an alternative audit firm that confronts the predecessor auditor in fewer market segments. Our evidence is consistent with mutual forbearance among rival audit firms when confronted with the same competitor in different market segments.

Economic incentives are fundamental for understanding auditor behavior. In this paper, we investigate the association between the extent of partners' fee-based compensation, partners' observable net wealth, and audit quality. Using a sample of Belgian Big 4 audit firms and their predominantly private clients, our results suggest a negative association between audit quality and partner fee-based compensation, and a positive association between audit quality and partner observable net wealth. Moreover, our results show that the latter association is most significant when a partner is carrying a lot of debt, which indicates that a partner's financial situation may affect audit quality. The extent of fee-based incentives also varies among partners of the same audit firm. Furthermore, partner and client characteristics differ based on the extent of fee-based compensation. Our findings should be of interest to regulators and audit firms, as they suggest that audit partners' economic incentives significantly affect audit quality. Data Availability: All data are publicly available from the sources identified in the text.