Audit market share and auditor's opinion: evidence from Iranian audit private sector

This study aimed to identify the impact of competition in audit private sector on auditor's opinion. Therefore, this study examines the effect of "market share" of the private audit firms on their audit opinion. Research period is from 2005 to 2012 and research sample consists of 72 firms that are listed at Tehran Stock Exchange. These firms were audited by 47 audit firms that are member of the Iranian Certified Public Accountants. The research methodology is correlation. Hypothesis was tested by multiple regression method. The results indicate that the more market share of private sector audit firms, the less number of clauses before the opinion paragraph. Furthermore, factors such as individual ownership, paragraphs in last year audit report, accumulated deficit and audit fee have effects on auditor opinion.