Alireza Malali Dezaki, Bahareh Banitalebi Dehkordi, Azar Moslemi, The Relationship Between Information Asymmetry, Disclosure and Cost of Equity Capital in Companies Listed in Tehran Stock Exchange, International Business Management, Volume 10,Issue 15, 2016, Pages 3084-3091, ISSN 1993-5250, ibm.2016.3084.3091, (https://makhillpublications.co/view-article.php?doi=ibm.2016.3084.3091) Abstract: The aim of this study is to examine the impact of information asymmetry between the cost of capital in 94 active and passive companies listed in Tehran exchange from 2006-2013. Results show that there is a significant relationship between active investors and information asymmetry as well as between active investors and capital costs in companies listed in Tehran Stock Exchange. Also, there is a significant relationship between passiveinvestors and lack of information asymmetry as well as between passiveinvestors and the cost of capital in companies listed on Tehran Stock Exchange. Keywords: Information asymmetry;disclosure;cost of capital;active and passive shareholders;Iran