JMGT_V11_N3_RP3 Shekoufeh Nekoueizadeh Yaser Shahbazi Journal on Management 2230 – 715X 11 3 27 40 Audit Quality, Tenure, Stock Returns, Trading Volume The present study is intended to investigate the relationship between quality of auditing with returns and size of stock deals in the companies admitted in the Tehran Stock Exchange. A number of 72 companies during 2006-13 time span were selected. Auditor tenure has been selected as the criterion by which auditing quality is appraised. Correlation coefficient between independent variables and dependent variable was, first of all, determined based on correlation matrix. For final conclusion about relationship between variables, results of regression model analysis were addressed. Moreover, Ftest is used to investigate linearity and significance of regression model. Coefficients of models have been estimated based on the Least Squares Model. In addition, T-test is applied for examination of significance of estimated coefficients. Independence of error components in the model has been fitted, for those investigation Durbin-Watson Statistics were used. Based on testing the research hypotheses, the relation between efficient auditor tenure and size of stock deals was found to be an inverse and significant relationship. December 2016 - February 2017 Copyright © 2017 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=8328