Capital market as the main and most important financing mechanism of enterprises in market-oriented or capitalist economies. Market financing can put less pressure on companies and support them on their way to success in their business. Stock price is considered as the most important indicator in capital markets, which can indicate the expectations and reactions of the market to the situation and performance of companies and other information and events in it. In the present study, the risk of falling in the stock price of companies on the power of the CEO (as the highest executive position in companies) has been investigated. The statistical population of the study includes 126 companies that were selected through screening in all companies. The time domain of the research is 1392 to 1397 and to test the hypotheses, multivariate linear regression method has been used in Stata software. The research findings show that there is a significant inverse relationship between the risk of falling stock prices and the power of the CEO, and also the size of companies has no effect on this relationship. The third hypothesis also showed that the financial knowledge of the CEO has a direct and significant effect on the relationship between the risk of falling stock prices and the power of the CEO, that is, if the CEO has financial knowledge, in the presence of risk of falling stock prices to increase its power By increasing its investment percentage.