A Buyer’s Guide to Assurance on Sustainability Information

Explore the complete guide & executive summary

Published

22 June, 2026

Type

Publication

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At that time, many organisations were beginning to explore assurance over emerging sustainability disclosures. The landscape has evolved rapidly, and sustainability reporting is now shaped by global and regional frameworks, including the International Sustainability Standards Board (ISSB) standards and the European Sustainability Reporting Standards (ESRS), raising expectations for how information is prepared, presented and used.

Sustainability information is increasingly used to support governance, risk management and capital allocation. As expectations from investors, regulators and other stakeholders continue to evolve, many organisations are seeking independent assurance to strengthen confidence in that information.


What this guide covers

This guide supports organisations through the full assurance journey, from understanding what assurance is, to preparing for it, selecting a practitioner and interpreting the results.

1. Basics of assurance

An overview of what assurance is, what it does (and does not) provide, and how it supports governance and decision making.

2. Understanding your assurance needs

Guidance on clarifying why assurance is being sought and how to scope it effectively.

3. Preparing for assurance

Practical support to assess readiness and identify areas for improvement.

4. Obtaining assurance

A structured approach to selecting an assurance practitioner and running a robust procurement process.

5. Working with your assurance practitioner

An overview of how assurance engagements typically operate and what organisations should expect.

Practical tools, insights and resources

The guide includes case studies, checklists and practical tips and insights to support readiness, procurement and oversight.

Who this guide is for

This guide is primarily intended for organisations acting as the ‘buyer’ of assurance, including:

  • finance and sustainability teams
  • risk, compliance and internal audit functions
  • procurement teams
  • boards and audit committees.

It may also be helpful to investors and other users of sustainability information.

It is applicable across sectors and geographies and can be used by organisations at different levels of reporting maturity.

This guide provides a timely and practical resource for boards, audit committees and senior management as they consider how to obtain assurance that is meaningful to investors, grounded in robust governance and controls, and transparent about its scope, level and limitations.

– Jen Sisson, CEO, International Corporate Governance Network (ICGN)

Why this matters

Effective assurance can:

  • improve the reliability and transparency of sustainability information
  • strengthen governance and oversight
  • enhance confidence among investors and other stakeholders
  • provide insights to strengthen systems, controls and reporting over time.

Used well, assurance is not only a compliance activity, but a tool to support better decision making and continuous improvement.

This report offers practical guidance for those navigating assurance decisions and highlights why the accountancy profession, with its expertise, ethical standards, and public interest commitment, is so well positioned to build confidence in sustainability information.

– Lee White, CEO, International Federation of Accountants (IFAC)

Buying Assurance with Confidence: What You Need to Know

The webinar combined a practical walkthrough of the Buyer’s Guide with a panel discussion exploring real-world experiences of preparing for, buying and using sustainability assurance. Watch the webinar here.