This study investigates the relationship between managers’ abnormal disclosure tone and opportunistic behaviour in managerial accounting, grounded in agency theory. Using a quantitative ex-post-facto design, we analysed data from 1411 annual reports of 143 companies listed on the Tehran Stock Exchange between 2008 and 2020. Finance-oriented dictionaries were employed to quantify abnormal disclosure tone, and a panel smooth transition regression model was used for analysis. The results reveal nuanced correlations between abnormal tone and various dimensions of opportunistic behaviour, including earnings management, management compensation, financial leverage, capital increase plans, and accounting conservatism. Notably, positive earnings management and financial leverage are positively associated with the abnormal tone, while capital increase plans are significant only in companies with negative earnings management. Contrary to expectations, accounting conservatism shows a positive relationship with abnormal tone. The findings highlight the need for companies to recognise and mitigate risks associated with opportunistic behaviour and provide insights for stakeholders in the financial sector. The study contributes to the literature by offering empirical evidence on the interplay between disclosure tone and managerial opportunism, with implications for corporate governance and decision-making

Keywords