Should companies use the same provider for financial statement audit and assurance of extended external reports?

Companies are increasingly reporting and assuring sustainability information. Once the decision to assure is made, a company must choose an assurance provider, but should the company use the same firm as its financial statement auditor or a different assurance provider? Lu, Simnett, and Zhou (2023) find that perceived independence concerns deter companies from choosing the same provider, while a provider’s assurance expertise and higher levels of information integration between the financial statements and the extended external report both increase the likelihood of using the same provider. Companies using the same provider for both services benefit from higher financial statement audit quality without paying significantly higher audit fees. The findings of this research are useful for companies in deciding whether to employ their financial statement audit firm to also provide assurance of extended external reports. The findings also have implications for auditors and standard-setters/regulators.