The International Auditing and Assurance Standards Board (IAASB) published the International Standard on Sustainability Assurance (ISSA) 5000, General Requirements for Sustainability Assurance Engagements in November 2024. ISSA 5000 is applicable across various sustainability topics and frameworks and is designed for use by both professional accountants and non-accountant assurance practitioners.

When used alongside the sustainability-related ethics and independence standards issued by the International Ethics Standards Board for Accountants (IESBA), ISSA 5000 provides a unified global approach to address the growing demand for trustworthy sustainability information to support stakeholder decisions.

The IAASB’s ISSA 5000 provides a principles-based framework for conducting assurance engagements on sustainability disclosures. The standard is designed to:

• Enhance Reliability and Transparency: Focused on enhancing the credibility of sustainability reports, ISSA 5000 addresses the growing need for verified sustainability information among investors, regulators, and stakeholders.
• Adapt to Global and Local Contexts: The standard is scalable and adaptable to regional regulatory requirements, such as the EU’s Corporate Sustainability Reporting Directive (CSRD), and can be used with any sustainability reporting framework or standard.
• Support Diverse Practitioners: Applicable to all assurance providers, ISSA 5000 ensures consistency and rigor, incorporating materiality concepts and proportionality for organisations of all sizes.

The ISSA 5000 is effective for assurance engagements on sustainability information reported:

1. For periods beginningon or after 15 December 2026; or
2. As at a specific date on or after 15 December 2026.

Earlier application of this ISSA is permitted.

The Institute has approved the adoption of ISSA 5000. The standard can be accessed here: International Standard on Sustainability Assurance 5000

The IAASB developed this implementation guide to provide practical non-authoritative guidance intended to assist practitioners in conducting assurance engagements in accordance with ISSA 5000.

To support practitioners, the IAASB has released new guidance and support materials, including an implementation guide (see above), fact sheet, Frequently Asked Questions document, and an FAQ video series.

• Fact Sheet: This fact sheet provides an overview and highlights of the ISSA 5000. It includes who the standard applies to, what it covers and what the standard provides to practitioners, stakeholders and those who rely on reported sustainability disclosures for decision making.
• Frequently Asked Questions: To support practitioners, the IAASB has released this Frequently Asked Questions document to address specific questions stakeholders may have.
• Joint IAASB-IESBA FAQs on Sustainability Assurance: These FAQs issued jointly by the IAASB and IESBA Staff address practical questions about applying ISSA 5000 and IESSA together.
• FAQ Video Series

The IAASB periodically update the focus area webpage with new support and implementation materials. The Focus Area webpage can be accessed here: Understanding The International Standard on Sustainability Assurance 5000

International Ethics Standards for Sustainability Assurance (IESSA)

The International Ethics Standards Board for Accountants (IESBA) has issued new sustainability-related standards for ethics and independence in sustainability reporting and assurance. Taken together with the ISSA 5000, these new and revised standards provide a unified global approach to addressing the growing market demand and calls from regulators and other stakeholders for trustworthy sustainability information to support stakeholder decisions.

Information on the IESSA can be accessed here: Global Ethics Sustainability Standards