The auditor–client relationship and abnormal tone: a simultaneous equations approach

Purpose Quantitative information alone provides an incomplete picture of a company’s economic performance; therefore, the analysis of textual disclosures is critical. However, evidence suggests that managers can use the tone of disclosures to conceal their opportunistic actions. This is because words are more flexible in conveying impressions than numbers, and qualitative disclosures are voluntary, giving managers almost complete discretion over them. In contrast, quantitative disclosures adhere to standards and are monitored by independent auditors or the capital market. This study investigates how the abnormal tone in managerial disclosures interacts with the auditor-client relationship, offering new insights into the strategic use of language in financial reporting. By focusing on this intersection, the paper contributes to the literature not by advancing text analysis methods per se but by applying them to uncover novel dynamics in auditor-client communication and disclosure quality. Design/methodology/approach Our research, which utilizes a sample of 1,529 observations from 139 companies listed on the Tehran Stock Exchange, covers the period from 2012 to 2022. We employ a simultaneous equations approach, a robust methodology that allows us to analyze the mutual impact of abnormal tone in disclosures and the auditor-client relationship. To ensure the validity of our findings, we conduct robustness checks to confirm that they are not sensitive to changes in the measurement method of auditor-client relationship durability. This rigorous approach instills confidence in the reliability of our results. Findings The results provide new evidence that the auditor-client relationship and managers’ use of abnormal tone have a mutually positive impact on each other. Additionally, managerial overconfidence and conservatism are found to moderate this relationship. Further analyses reveal that the abnormal tone from the previous year also directly affects the auditor-client relationship, highlighting the persistence of these effects over time. Originality/value This research contributes to the literature by applying textual analysis to a novel context—auditor-client dynamics rather than proposing a new method. It highlights how the auditing environment influences qualitative disclosures, particularly tone and influence. These findings have practical implications for auditors, regulators, and investors. They emphasize the need to consider quantitative and qualitative signals in evaluating corporate transparency and governance.