Examining the performance of companies is one of the most important issues for the attention of managers, investors, creditors and other interested parties, and the results are the basis of many decisions inside and outside the companies. The purpose of this research is to study the effect of active institutional ownership on performance volatility. The statistical research population of companies admitted to Tehran Stock Exchange and the studied sample includes 140 admitted companies during the years 2015 to 2019. The research method is descriptive and correlational in terms of the relationship between variables, and it is practical in terms of purpose. The regression method and panel data as well as the fixed effects model were used to process and test the hypotheses. The results of the hypothesis analysis showed that active institutional ownership has a positive and significant effect on performance volatility. According to the results of the research, managers are suggested to pay more attention to the opinions and ideas of active institutional owners in order to play a supervisory role on the company's performance, because the supervisory role of active institutional owners and increasing the quality of supervision increases the quality of corporate management, which ultimately results in transparency. Information and improving the quality of financial reporting follows.