The goal of this research is to study the stock prices influence due to dividend during decreasing or increasing period of Tehran Stock Exchange index. Moreover, this research studies the difference between companies which have or have cot distributed dividend during decreasing period of index of index versus increasing period. This research consists period of 1384 to 1389 which has 34 months of decreasing period index and 38 months increasing period index. To have access to research goals, 254 companies in two separated group (which have distributed divident or have not ) have chosen and using t-test research hypotheses have been studied. Results of research suggest that dividend distribution during decreasing period versus in creasing has no significant effect on listed companies of Tehran Stock Exchange. Moreover, results show that yearly stock returns during these two period have significant difference between companies which have distributed dividend or have not.
