Abstract
This study aims to test the information content of sustainability reports issued by the most significant telecommunications companies operating in the Kingdom of Saudi Arabia (Stc, Zain, and Mobily), and their compatibility with the national sustainability standards issued by the Ministry of Commerce in the Kingdom of Saudi Arabia in light of the Kingdom's vision 2030, and its impact on the stock exchange indices of these companies. The event study methodology was used to study the impact of publishing sustainability reports on stock prices and the trading volume of these companies' shares in the Saudi stock market during the period from (October 2020 to March 2021). The results indicate a significant impact of the information contained in the sustainability reports on stock prices and trading volume in the stock market, and the importance of directing the company's management towards more disclosure of information about sustainability in its environmental, social, and economic aspects instead of focusing only on information related to the financial performance and economic activity of the company. This encourages the listed companies to disclose the sustainability of the financial reports and standardize the form in which these disclosures are prepared.