Why assurance matters

Sustainability reporting has changed. The scrutiny is here.

Your sustainability data now sits alongside the numbers in your annual report. Regulators are already flagging deficiencies, investors are asking harder questions and, in some cases, assurance is now required. 

Boards are also increasingly expected to stand behind the controls over what they report, across both financial and non-financial numbers. But sustainability information isn’t financial data. It’s newer, spread across many teams and systems, and rarely backed by the mature controls behind your financial numbers. It’s also heavy with judgements, estimates and boundary decisions that aren’t always clearly explained. That makes it easier to get wrong, and easier for stakeholders to doubt or misinterpret. 

Meeting that expectation takes investment in data, people, processes and controls. Independent assurance is how you show that what you report is reliable, and how you find out where it isn’t.

How we work

Why Grant Thornton

We tailor every engagement to your risks, data processes and controls, and design our testing around them. We work in accordance with recognised international assurance standards, not merely based on them. Our people are involved with the bodies shaping sustainability reporting and assurance, so our approach keeps pace as the rules change. Alongside our conclusion, you get practical feedback on your processes, your data and the report itself, so the value lasts beyond this year’s report.

Additional services

Know where the gaps are before anyone else tests them. We get under the bonnet of your processes, risks and controls and tailor the work to your needs. Ideal if you’re reporting or being assured for the first time. Our readiness assessment is the first stage of our assurance approach, so nothing is repeated if you go ahead, and you can often reach a published conclusion in the same reporting cycle.

Put your name to numbers you can stand behind. We test your information and give an independent conclusion (limited or reasonable), along with feedback on your draft report and a confidential report for management with our key observations.

Get in touch

Paul Holland

Partner, Head of ESG and Sustainability Services

Frequently asked questions

If you report sustainability or other non-financial information outside your organisation, it’s worth considering. It matters more if investors, lenders or customers are asking, or if your reports describe processes, like your materiality assessment, that would benefit from independent challenge. And if your financial information is audited, why treat your sustainability information differently?

Not always, but it’s increasingly expected, and sometimes it’s required as part of financing mandates. It depends on your size, structure and where you report, and the requirements are still changing. We’ll help you work out where you stand.

Start by asking whether your processes make your information relevant, complete, reliable and understandable. If you’re not sure, a readiness assessment will tell you.

Reasonable assurance gives a high level of confidence, closer to a financial statement audit. Limited assurance involves less testing and gives a lower, but still meaningful, level of confidence. We match the level to how mature your reporting is, from a first limited assurance conclusion on a few metrics to reasonable assurance across your full report, and can extend the scope as your reporting matures.

We work in accordance with the International Standard on Assurance Engagements (ISAE) 3000 (Revised) and, for greenhouse gas information, ISAE 3410. We also work to ISSA 5000, the new global standard for sustainability assurance. We update our approach as the standards change.