ACCA and Chartered Accountants Australia and New Zealand (CA ANZ) have released a guide to aid practitioners in understanding and implementing the new International Standard on Sustainability Assurance 5000 (ISSA 5000).

The guide is a response to the publication of ISSA 5000 by the International Auditing and Assurance Standards Board, which intends to enhance trust in sustainability reporting and mitigate the risk of greenwashing.

Mandatory sustainability reporting, particularly for larger companies, has been on the rise lately.

The alliance between ACCA and CA ANZ has produced the first in a series of guides that address the critical aspects of ISSA 5000.

The inaugural guide, titled ‘A case study: Demystifying materiality in accordance with ISSA 5000’, zeroes in on the concept of materiality within sustainability assurance engagements.

ACCA head of Audit and Assurance Antonis Diolas said: ‘The trust and confidence of investors, regulators and other stakeholders in sustainability assurance is vital if sustainability reporting is to be successful in bringing about a more sustainable approach to business.

‘This guide is intended to support assurance practitioners in applying professional judgement when planning and performing sustainability assurance engagements under ISSA 5000. It’s critical that assurance practitioners focus on the most significant aspects of sustainability reporting, which are most likely to influence the decisions of intended users.’

CA ANZ Reporting and Assurance leader Amir Ghandar said: ‘Materiality is no longer a buzzword – it’s the backbone of credible sustainability assurance. This guide offers clarity where it’s most needed. As sustainability reporting and assurance become mandatory across jurisdictions, ISSA 5000 sets the global baseline – and this guide helps practitioners apply it with confidence.

‘Applying materiality in sustainability assurance isn’t just about numbers, it’s about understanding what truly matters to stakeholders. This guide shows how. The case study bridges the gap between theory and practice, helping assurance practitioners navigate the nuanced judgement calls required for materiality under ISSA 5000.’

The guide emphasises the significance of the materiality phase, urging practitioners to recognise the various points where professional judgement is required.

It also advises on the allocation of adequate time to apply the standard’s requirements effectively, including thorough documentation.

The outcomes of the materiality stage are expected to aid in shaping the practitioner’s approach to evidence collection and evaluation of any misstatements in sustainability reports.

The guide illustrates the application of materiality to Scope one, two, and three greenhouse gas emissions through a hypothetical assurance engagement.

In October 2024, CA ANZ and ACCA announced the joint publication of the ‘Audit and Technology Playbook: A Practitioner’s Guide’, to enable audit professionals to traverse advancements in technology, including AI, machine learning, and blockchain.