Governance
ISAE 3000
The IAASB's umbrella assurance standard for engagements other than audits or reviews of historical financial information, long the default standard for assuring sustainability reports.
Definition
ISAE 3000 (Revised), Assurance Engagements Other than Audits or Reviews of Historical Financial Information, is the International Auditing and Assurance Standards Board's general standard for non-financial assurance. It sets requirements for acceptance, planning, evidence, quality management and reporting in both reasonable and limited assurance engagements, and has been the principal standard for assuring sustainability and ESG reports.
References
Umbrella-standard role, EER guidance, limited vs reasonable assurance
Approval (2013), effective date December 2015, scope
Overview
What it means
Because financial-statement auditing standards do not fit sustainability information, ISAE 3000 fills the gap: it defines how a practitioner obtains sufficient appropriate evidence to conclude, in either positive (reasonable) or negative (limited) form, whether subject matter such as a GHG statement or ESG report is free from material misstatement against suitable criteria.
How it is used
Assurance providers cite ISAE 3000 in limited or reasonable assurance opinions on corporate sustainability reports, often alongside ISAE 3410 (greenhouse gas statements) or AA1000AS. From periods beginning on or after 15 December 2026, sustainability engagements migrate to its dedicated successor, ISSA 5000, while ISAE 3000 continues to govern all other non-financial subject matters.
Why it matters
It gave sustainability assurance a recognised, enforceable methodological base, underpinning regulatory regimes such as the EU's CSRD limited-assurance phase and investor-grade ESG data. **Note:** Companion entry: ISSA 5000 (this batch), which supersedes ISAE 3000 for sustainability subject matters.
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