The Effect of Audit Market Concentration on Audit Opinion

The purpose of this study was to investigate the impact of audit market concentration on audit opinion. The statistical population of this research were the companies listed on the Tehran Stock Exchange during 2017 to 2021, which was selected as a statistical sample by the method of systematic elimination of 126 companies. With due attention to the independent variable (audit market concentration impact), we looked for their audit firms. Library research method was used to collect data, while descriptive-inferential statistics were used to test the hypothesis. The result of the hypothesis showed that audit market concentration has a positive effect on the type of auditor's opinion. This means that the more auditors’ concentration on the client industry, the higher the quality of the audit work and the type of opinion becomes more acceptable. In addition, the effect of the auditor size on the type of opinion is positive and in contrast the effect of delay in submitting the auditor's report on the type of opinion is negative.