The main purpose of this research is investigation the effect of clean opinions, big four of Auditor on the level of clients’ Tax Avoidance. The auditor expertise in an industry is constructive ideas to help clients, providing fresh insights and solutions to some of the issues that are faced by clients in their respective industries. Tax Avoidance and evasion in countries has caused that the country's tax revenue is estimated to be less than that. As industry experts have superior knowledge and experience than are lay, therefore, clients receive tax audit from auditors are expert in comparison to other auditors.
Present research is study of applied and causation research which in that the effects of single and dual expertise in the industry on corporates tax avoidance in to help 9 hypotheses were investigated.
The study sample consisted of 71 companies for the period 2004 to 2014 were studied. Research hypotheses by using Heckman two-stage procedure and panel data statistical methods have been tested.
The results show that nonclean opinions and big auditors have an effect on corporate tax avoidance. In other words, the companies that their auditors are the nonclean opinions and big auditors, have lower cash effective tax rates.