Our summary
ISSA 5000 is the IAASB’s standard for assurance engagements on sustainability information. It was published in November 2024 and is effective for periods beginning on or after 15 December 2026. It is a complete, stand-alone standard that can be used for any sustainability topic and with any suitable reporting framework. The IAASB also publishes extracts for limited assurance and reasonable assurance engagements, an implementation guide and other support material.
The standard is profession agnostic. This means it can be used by professional accountants and also by assurance practitioners who are not accountants. It is designed to work together with the IESBA ethics and independence standards for sustainability assurance. The IAASB page also notes that the European Commission is developing rules for mandatory limited assurance based on ISSA 5000.
How auditors use it: Internal auditors can use ISSA 5000 to understand what external assurance providers will test in sustainability reports, and to prepare data, controls and evidence before that work starts. It also gives a clear model for internal reviews of ESG reporting. Audit committees and compliance leaders can use it to judge the scope and quality of the sustainability assurance they receive.