The main purpose of this study is to test the effectiveness of capital market efficiency through the mediating variable of political cycles based on the theory of constraint on the rate of total stock returns for manufacturing companies listed on the Iranian Stock Exchange. In this regard, first, the theoretical foundations and internal and external background of the research have been examined and in the next step, a sample of 178 companies from manufacturing companies based on the fixed effects method, and for two research models the estimation of panel econometric models has been done. In the next step, the research model was estimated by considering the variables of political cycles for the period of 1384 to 1392 (political period of fundamentalism) and also the period of 1392 to 1398 (non-fundamentalist political period). The results showed the negative effect of the political cycle variable in the fundamentalist period and the positive and significant effect of the political cycle variable in the non-fundamentalist period on the stock return rate. In the end, suggestions were made to improve the stock rate of return of listed companies based on the results. تفاصيل المقالة