Selecting a sustainability reporting assurance provider: The 2026 buyer’s guide 

Choosing a sustainability reporting assurance provider is a strategic decision 

Selecting the right assurance provider shapes disclosure credibility and the trust of investors and stakeholders. Yet many organisations approach the selection process without a clear evaluation framework. 

That is why we created this 2026 buyer’s guide: a practical resource to help ESG and sustainability leaders evaluate assurance providers with clarity and confidence. 

What’s inside the guide? 

This guide provides a structured approach to selecting a sustainability reporting assurance provider and covers: 

• why sustainability reporting assurance is a strategic decision 

• the differences between assurance levels and scope 

• a practical checklist for evaluating providers 

• key questions to ask during the selection process. 

Whether you are appointing an assurance provider for the first time or reassessing your current engagement, this guide provides the structure and clarity you need to make the right decision.