What is the Role of Audit Opinion in the Relationship of Audit Tenure, Company Size, and Audit Delay to Audit Costs?

This study aims to examine the influence of audit tenure, company size, and audit delay on audit fees, with audit opinion serving as a moderating variable viewed through the lens of agency theory. The research employs a quantitative approach using panel data from manufacturing companies listed on the Indonesia Stock Exchange over a five-year period. The findings indicate that longer audit tenure and larger company size tend to increase audit fees, while audit delay does not have a significant impact. The analysis further reveals that audit opinion strengthens the relationship between audit tenure and audit fees, but does not alter the effect of company size or audit delay. These results suggest that extended auditor-client relationships and the scale of business operations contribute to higher audit complexity and consequently greater audit costs. The study provides theoretical implications by deepening the understanding of factors influencing audit fee determination and practical insights for auditors, corporate management, and regulators in promoting fairness, transparency, and high-quality audit practices within the corporate governance framework.