IAASB and IESBA debut sustainability assurance standards

The International Auditing and Assurance Standards Board and the International Ethics Standards Board for Accountants formally launched their sustainability assurance, reporting and ethics standards Monday along with a related IESBA standard on using the work of experts.

The standards aim to establish clear expectations for ethical behavior in sustainability reporting and assurance and provide more specific requirements for practitioners and organizations in relation to assurance engagements on sustainability information. The IAASB’s International Standard on Sustainability Assurance (ISSA) 5000 and the IESBA’s International Ethics Standards for Sustainability Assurance (IESSA) provide a set of interoperable global standards for assurance, ethics and independence for sustainability assurance engagements. Along with those standards, IESBA has also released guidance on using the work of an external expert to guide accountants or sustainability assurance practitioners in evaluating whether an outside expert has the necessary competence, capabilities and objectivity. Among the goals are reducing the risks of fraud, including greenwashing, and noncompliance with laws and regulations. The standards can work in tandem with the International Sustainability Standards Board’s standards and other sustainability reporting frameworks.

“The interoperable package of ISSA 5000 and IESSA represents an important evolution in global sustainability reporting and assurance,” said IAASB chair Tom Seidenstein in a statement. “These standards establish the necessary technical and ethical pillars to ensure that qualified practitioners could consistently perform high-quality assurance engagements on sustainability information.”

IESBA announced earlier this month that it and the IAASB would be officially launching the standards on Jan. 27 after they were certified by the Public Interest Oversight Board and the International Organization of Securities Commissions. Nevertheless, the release of the standards comes as the U.S. appears to be backing away from environmental, social and governance efforts, with states like Florida and Texas passing anti-ESG laws. The Securities and Exchange Commission’s climate-related disclosure rule has been on hold since last April due to industry lawsuits. After the inauguration of President Trump last Monday, he quickly signed an executive order calling for the U.S. to withdraw from the United Nations’ Paris climate agreement. In the European Union, the Corporate Sustainability Reporting Directive has taken effect, but France and Germany are urging the EU to scale back the CSRD requirements, given the economic pressures in their countries.

Nevertheless, the IAASB and IESBA, which are both affiliated with the International Federation of Accountants, see demand from investors for verifiable and trustworthy information on companies’ sustainability efforts and that’s where accountants and auditors can help.

“Ethics is the foundation of trust,” said IESBA chair Gabriela Figueiredo Dias in a statement. “With these standards, we are equipping preparers and practitioners with the tools needed to uphold integrity and foster transparency in sustainability reporting. Together, the IAASB and IESBA are setting a global standard for accountability and professionalism.”

In jurisdictions adopting the standards, both ISSA 5000 and IESSA become effective for periods starting on or after Dec. 15, 2026, with early adoption permitted and encouraged. The IAASB and IESBA plan to provide ongoing support through webinars, implementation guidance and continued implementation monitoring and feedback channels to ensure smooth and effective adoption.

To help stakeholders understand and use the new standards, the IESBA is holding a series of webinars at various times to accommodate a global audience:

• IESBA Sustainability-related Ethics and Independence Standards 
  • IESBA Sustainability Overview and Sustainability Reporting 
  • Key Topics in the IESSA 
  • IESSA Independence Standards: A Deep Dive 
• Using the Work of an External Expert