The function of social media and it's awareness and information can play a significant role in the changes in stock prices and investors' decision making. Fluctuation is an important measure of financial performance that reflects uncertainty or risk. In view of this, the present study investigated and analyzed the social media and the fluctuations of the Tehran Stock Market during the period of April 2011 to August 2021 using auto-regression model. The results show that the instantaneous reaction functions of the stock returns of active companies in the Tehran stock market to the changes in the social media, the number of shares of the companies, the infected and the dead of covid-19 were positive until the third and fourth periods, and after the mentioned periods of shock entered into the explanatory variables did not have an effect on the fluctuation of the companies' returns. Also, the results of the analysis of variance showed the high effects of the number of shares of the companies in the changes of the efficiency of the companies and the effect of social media in explaining very slight changes in fluctuations have been observed
