The Information Content of Audit Opinion with Emphasis on Auditor's and Client's Sizes

Audit process as a control mechanism increases informativeness and credibility of financial statements and is one of the effective ways of facilitating decision-making in capital markets. The purpose of this applied research with a descriptive correlative native is to investigate the information content of an auditor’s opinion with emphasis on auditor’s and client’s sizes among companies listed in Tehran Stock Exchange (TSE). In order to achieve the goals of the research, 145 companies listed in TSE were selected for the period of 2010-2016, by using the systematic selection sampling method. After categorization of the selected companies, 1015 year-firm data were taken as the main sample. In order to study the relationship between the variables, multiple regression models were used, and the regression models were fitted with the generalized least squares method. Findings showed that all three types of auditor’s opinion (unqulified, unqualified with explanatory paragraph, and qualified) have information content. Also, the auditor's size did not affect any one of auditor’s opinions. In other words, from the relationship between auditor’s size and the information content of the type of the audit report, the form of the report is preferred over its substance. This means that in general, the capital market interprets a particular type of auditor’s opinion in a same way. Moreover, client’s size affects information content of unqualified and qualified auditor’s opinion, but does not affect unqualified auditor’s opinion.