M.A. Thesis:

audit firm rotation and audit quality٫ audit fees and audit market concentration

Considering the position and role of audit firms in users' decisions, audit quality is considered as a key factor in preparing audit reports. The present paper seeks to examine the effect of the mandatory audit firm rotation on audit quality, audit fees and audit market concentration of companies admitted to the Tehran Stock Exchange Deals. To this end, information was collected on 140 active companies in the stock market during the years 2014 to 2018 and analyzed using the software EVIEWS. The research method for the hypotheses are multivariate regression and the panel data. Based on the results of research and statistical tests, it can be said that there is a positive and significant relationship between the mandatory audit firm rotation and audit quality. Also, there is a positive and significant relationship between the mandatory audit firm rotation and audit market concentration. But, there is no a significant relationship between the mandatory audit firm rotation and audit fees. The increase in auditor change in recent years help the auditor's ability to play an important role in the financial statements.

Keywords: Mandatory Audit Firm Rotation, Audit Quality, Auditor Fee, Auditor Market Focus