Forward-looking forecasts made by managers are dependent on the company's earnings performance, which in turn may affect the quality of managers' forecasts for forward-looking information disclosure. The main objective of this study is to investigate the relationship between changes in forward-looking information disclosure and the value of companies with good and poor performance. For this purpose, 178 companies listed on the Tehran Stock Exchange between 2013 and 2023 were selected using the systematic elimination method, and in order to increase the degree of confidence in the results of hypothesis testing, static and dynamic panel data regression methods were used. According to the research findings, in both static and dynamic cases, the variable of change in forward-looking information disclosure has a positive and significant effect on the value of the company with two criteria (Q-Tobin and adjusted Q-Tobin). Also, changes in forward-looking information disclosure have a significant effect on Q-Tobin and adjusted Q-Tobin with good and poor performance in both models. The annual disclosure and modification of forward-looking information, or the failure to disclose and modify it, has consequences for companies and managers of both well-performing and poorly-performing companies. Despite the requirement for companies to disclose forward-looking information in accordance with the Executive Order on Disclosure of Information by Listed Companies, managers with various motivations may change or not change the annual disclosure of forward-looking information.