Big four premiums in the Spanish audit market and monopoly power

Abstract

This study seeks to investigate the effect of market competition as a moderator factor of Big Four fee premiums. Unlike previous studies, we measure market competition by structural variables, such as market concentration or entry barriers, and dynamic variables of market mobility, based on variations in the market shares of audit firms. Using a sample of Spanish non-financial listed companies over the years 2003–2010, we find that Big Four premiums are not explained by the level of competition within the market. Our findings are opposed to those of academics and regulators who consider that Big Four auditors earn higher fees through the exercise of market power. These results reinforce the idea that Big Four premiums are driven by audit firms’ reputation as providers of quality-differentiated audit services.