What are the economic consequences of mandatory joint audits?

Since 2005, France is the only European country requiring mandatory joint audits for companies listed on the stock market. In the Green Paper issued in 2010, entitled “Audit policy: Lessons from the crisis”, the European Commission proposed the introduction of mandatory joint audits for European listed companies to limit audit market concentration.

However, the new European regulation passed in 2014 does not include the obligation to hire two auditors who co-sign the audit report. Nevertheless, some countries (e.g., The Netherlands, the UK) still discuss the opportunity to introduce mandatory joint audits, which leads us to ask the following question: Should other countries introduce mandatory joint audits or should France abandon this specific system? To provide some answers to this question, we summarize the academic literature on joint audits in France to better understand its economic consequences.

Overall, empirical research shows that, when compared to other European countries, the French market is not less concentrated (in terms of audit fees captured by Big 4 firms), but companies pay more audit fees without any significant improvement in audit quality (and financial reporting quality). Additional evidence shows that audit quality and audit fees are sensitive to the pair of auditors. However, balanced worked between a Big 4 firm and a non-Big 4 firm, which was suggested by the European Commission, does not lead to a better quality-price ratio of audit services.

Taken together, the findings suggest that the joint audits system is not efficient, because the quality-price ratio of audit services in France is worse than that of other countries. Based on the Danish experience, we posit that the abandonment of mandatory joint audits in France may reduce audit fees without any reduction of audit quality.