Tax Litigation and Characteristics of Audit Opinions: Implications for Transparency and Trust in B3

Purpose. This study investigates how tax litigation affects the length, tone, clarity, and complexity of audit opinions for companies listed on Brazil’s B3 exchange, and the implications for financial reporting transparency and trust. Design/methodology/approach. A fixed-effects panel analysis is applied to 233 firms (3,241 firm-year observations) from 2009 to 2023. Tax litigation is measured as the ratio of tax-related provisions and contingencies to total assets. Audit opinion attributes (length, tone, readability, complexity) are quantified alongside various control variables (firm size, risk, etc.). Hypotheses are tested using regression and quantile regression. Findings. Higher tax litigation is associated with shorter audit opinions that paradoxically exhibit greater clarity and more technical complexity. Auditors appear to provide more focused, readable reports with additional technical details for firms facing significant tax disputes. Other factors (e.g., firm size, risk, governance) also show significant effects on audit opinion metrics. Originality. This study is the first to identify tax litigation as a significant determinant of audit report characteristics in Brazil. It extends the literature by demonstrating how auditors adjust their reporting strategy under high tax-risk conditions, balancing thorough disclosure with concise communication. Practical implications. Managers should strengthen tax compliance and governance to reduce litigation-related reporting complexities. Regulators might simplify tax codes to mitigate disputes and associated audit burdens. Auditors should enhance documentation and clarity when auditing clients with high tax risk to uphold transparency and stakeholder trust.