This study aims to examine the effect of shareholder concentration on audit fees
of firms listed on the Stock Exchange of Thailand during the period 2020–2022.
The research is grounded in agency theory and corporate governance frameworks.
The sample consists of 1,467 firm-year observations, with data obtained from
consolidated financial statements and annual registration statements (Form 56-1)
retrieved from the SET SMART database. The data were analyzed using descriptive
statistics, correlation analysis, and multiple regression analysis.
The results indicate that shareholder concentration is significantly and negatively
associated with audit fees. Firms with a higher degree of ownership concentration
tend to pay lower audit fees, as large shareholders play an important monitoring role
that leads auditors to assess lower audit risk and reduce audit scope. In addition,
firm size, firm complexity, risk level, and CEO duality (the chairman of the board
simultaneously serving as the chief executive officer) are found to have a statistically
significant effect on audit fees. The findings provide useful implications for auditors in
assessing audit risk and determining appropriate audit fees.