Studying the Effect of Market Competition on the Auditing Fees and the Operational Costs Efficiency as the Agency Costs Indexes

In the study the effect of market competition on the agency costs was examined in the companies listed in Tehran stock exchange; hence, 56 companies were examined in 2005–2010. The selected approach benefits from Panel Data to test the hypotheses and the natural logarithm of auditing fees and operational costs ratio were considered to calculate the agency costs. The findings indicate that there is significant relation between the competition effect in the product market and agency costs when the confidence rate is 95 percent; also the findings indicate that the debt rate has no significant effect on the agency costs.