حمیدرضا حاجب

Abstract Objectives: This study aims to examine the effect of sustainability reporting disclosure on the information content of earnings, with a focus on the moderating role of market competition. Methodology/Design/Approach: A sample of 146 firms listed on the Tehran Stock Exchange from 2014 to 2023 was selected using the systematic elimination method. The study employed a multiple linear regression model based on panel data to test the research hypotheses. The information content of earnings was assessed, and a disclosure checklist was used to evaluate the extent of sustainability reporting. Findings: The results indicate a direct and significant relationship between sustainability reporting disclosure and the information content of earnings. Additionally, market competition significantly influences this relationship, enhancing the impact of sustainability disclosure on earnings informativeness. Innovation: This study contributes to the literature by providing empirical evidence on how sustainability disclosure and market competition jointly shape the quality and informativeness of financial reports. The findings highlight the growing importance of sustainability performance in enhancing the transparency and credibility of earnings, especially in competitive markets. The results emphasize that improved disclosure practices, supported by a competitive environment, can enhance the value relevance of accounting information for stakeholders.