Implementing mandatory audit firm rotation: effects on audit and non-audit fees

The 2014 reform of the European Union (EU) regulation on auditing includes mandatory audit firm rotation and a significant limitation of the provision of non-audit services by the audit firm to their existing clients.This paper analyses the changes in audit fees, and non-audit fees, as well as in their proportion, when thereis a switch of audit firms, before and after the new regulation. The analysis is carried out for the Spanish listed companies from 2011 to 2018 using two types of analyses, descriptive/comparative and multivariate,panel data, regressions. As expected, the new EU regulation has resulted in a significant increase in audit firm switches. The results show that, when there is a change of audit firm, the incoming firm offers a significant discount to the new client with the outgoing firm. This is the case before and after the reform, and for both voluntary and mandatory switches after the reform. In addition, the reform has led to a reduction of non-audit fees, which is especially evident after a voluntary audit firm switch. We conclude that audit firms seem to be willing to take on the additional cost of auditing a new company to gain clients.