Choice of financial audit firm and ESG assurance firm: The role of board of director characteristics

Corporations increasingly seek assurance on their published environmental, social, and governance (ESG) reports. Some companies use their audit firm to assure ESG reports, while others seek assurance services from a different firm. This paper investigates the influence of boardroom-based factors – female directors and multiple directorships – on companies' choice of ESG assurance provider. Using a sample of 438 Australian company-year observations from 2010 to 2020 we find that companies with more female directors and busy boards (i.e., boards with directors having at least three concurrent directorships) are more likely to choose a Big-4 audit firm different from their incumbent financial auditor to assure their ESG reports. Based on agency, social capital and resource dependence theories, we explain this ESG assurance procurement strategy as deliberate to address the potential ethical dilemma of engaging the same audit firm for assurance of financial and non-financial information. Our findings suggest that companies with more female directors and busy boards are likelier than their counterparts to apply this ethical stance in choosing their financial auditors and ESG assurers. Implications for policymakers and regulators in designing board diversity guidelines or rules and companies in setting board diversity criteria and policies are discussed.