1. What is ISSA 5000?

The International Auditing and Assurance Standards Board (IAASB) has published ISSA 5000, a landmark sustainability assurance standard designed to meet the growing demand for globally applicable ESG-specific assurance. Unlike ISAE 3000, which lacked detailed ESG guidance, ISSA 5000 is purpose-built for sustainability assurance, offering greater structure, consistency and clarity for these engagements. 

ISSA 5000 is a comprehensive, standalone framework suitable for all types of sustainability assurance. Importantly, it is designed for use by both sustainability specialists (such as ERM CVS) and statutory financial auditors, broadening accessibility and applicability across the market. 

2. What ISSA 5000 means for you

ISSA 5000 sets a new global benchmark for sustainability assurance, replacing ISAE 3000 for ESG-related engagements. This transition will help ensure your reporting aligns with international good practice and strengthens credibility with stakeholders. 

While assurance providers will manage most of the change, reporting organizations may need to make minor adjustments, such as refining data processes or governance, to meet enhanced requirements. These changes are designed to improve clarity and consistency, not add unnecessary complexity. ISSA 5000 also supports compliance with emerging national climate disclosure regulations, including: 

California’s Climate Corporate Data Accountability Act (SB 253), which mandates rigorous climate-related disclosures for large companies starting from 2026 

Australia’s AASB S2 Climate-Related Disclosures for entities under the Corporations Act 2001 in a phased approach, where the disclosures must be assured in accordance with ASSA 5000, starting 2026

By adopting ISSA 5000, your assurance process will be better positioned to meet these requirements and reinforce stakeholder confidence in your ESG reporting. You can read more on the California Climate Bill SB 253 and the assurance requirements here. 

3. When will ISSA 5000 be adopted?

ISSA 5000 takes effect for reporting periods starting on or after 15 December 2026, although some jurisdictions are adopting it earlier. In most cases, the earliest fullyear reporting period under the standard would be 1 January to 31 December 2027. 

Many assurance providers, including ERM CVS, are transitioning early.  Not just for compliance, but to give clients a head start on clearer engagements, alignment with new regulations, and stronger stakeholder confidence, without last-minute pressure. 

4. ERM CVS and ISSA 5000: Shaping the future of assurance

ERM CVS isn’t just preparing for ISSA 5000, we helped shape it. At the request of the IAASB, our team provided expert feedback on the draft standard, influencing its development and refinement to ensure it meets the needs of businesses worldwide. 

We’re also part of the ISSA 5000 Technical Implementation Contact Group (TICG), working alongside global experts to guide practical implementation and interpretation. When you partner with ERM CVS, you’re working with an assurance provider that’s not only ready for ISSA 5000 but actively driving its adoption and best practice. 

6. Want to learn more?

ISSA 5000 is reshaping the future of sustainability assurance, and ERM CVS is here to guide you through the transition. 

Get in touch with our team today to understand what ISSA 5000 means for your reporting and how we can help you stay ahead of regulatory and stakeholder expectations. 

Find out more about our assurance services here or connect with us directly here