IESBA Releases Guidance on External Experts and Sustainability Assurance

Posted 17 September 2025 Written by Acts Online
Category Financial and Accounting

Brought to you by SA Accounting Academy: The International Ethics Standards Board for Accountants (IESBA) has released two new staff implementation publications to support the global adoption of its upcoming ethical standards on using external experts and sustainability assurance.

In terms of the upcoming revisions to the IESBA Code of Ethics, which are closely monitored by South African regulatory bodies such as the Independent Regulatory Board for Auditors (IRBA), these publications provide critical guidance on the Using the Work of an External Expert standard and the International Ethics Standards for Sustainability Assurance (including International Independence Standards) (IESSA). Both standards will officially come into effect for periods beginning on or after 15 December 2026.

The first publication is a 16-page staff Question and Answer (Q&A) document designed to assist professional accountants in public practice, professional accountants in business, and sustainability assurance practitioners (SAPs). It addresses common queries regarding the ethical obligations, competence, and objectivity assessments required when relying on the work of an external expert.

The second publication is a 10-page document highlighting the proportionality of the IESSA. This guidance is specifically geared towards small and medium practices (SMPs) to facilitate their implementation of the global ethics and independence baseline for sustainability assurance engagements (SAEs) across entities of all sizes.

The relevant resources and publications can be accessed directly via the following links:

  • Read the IESBA staff Q&A on using the work of an external expert here.
  • Access the final pronouncement on using the work of an external expert here.
  • Access the IESBA sustainability resources and IESSA guidelines here.

What this means for you, your business, or your clients

  • For yourself: As an auditor or professional accountant, you must familiarise yourself with the enhanced ethical and independence obligations when evaluating the competence and objectivity of external experts ahead of the December 2026 effective date.
  • For your business: Firms, particularly small and medium practices (SMPs) planning to offer sustainability assurance services, must review and align their internal quality management systems with the proportional framework of the IESSA.
  • For your clients: Clients preparing sustainability reports or requiring external valuations will face more rigorous inquiries from their assurance providers regarding the credentials, methodologies, and independence of the third-party experts they employ.

Originally published at https://accountingacademy.co.za/news/read/iesba-new-guidance-re-external-experts-and-sustainability-assurance

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