Assurance

Independent checking of reported sustainability data by a third party, to give readers more confidence in it.

Assurance comes in two levels: limited and reasonable. Many rules, including the CSRD, start with limited assurance and move towards reasonable assurance over time. Providers are usually audit firms or specialist verifiers.

Find providers and guides

• ESRS providers
• California SB 253/261 providers
• Assurance and audit

Related terms

• Limited assurance
• Reasonable assurance
• Audit trail

Guides

• What assurance providers ask for in a sustainability report
• How to prepare your first VSME sustainability report
• Double materiality assessment: a step-by-step process

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Reviewed 14 October 2026. General information, not legal advice.