All publicly traded companies in the United States are legally required to have their financial statements vetted by independent auditors. And plenty of other firms hire external auditors to enhance their credibility in the eyes of investors and other stakeholders. But what about the ESG reports that most large firms now voluntarily publish? How commonly are such nonfinancial disclosures subjected to third-party verification, or “assurance,” as accountants call it? Does that scrutiny have any effect on the quality of those disclosures?

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