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Definition

Sustainability assurance

Sustainability assurance is an independent assessment of defined sustainability information against named criteria, ending in a report that states the provider's conclusion and level of assurance.

What is sustainability assurance?

Sustainability assurance applies to a defined set of disclosures, which can include climate, water, workforce or governance information. An independent provider evaluates that information against named criteria, tests supporting records and issues a signed report stating its conclusion and assurance level. GHG verification is narrower because it focuses on a greenhouse gas statement.

Why does sustainability assurance matter to you?

Customers, investors and reporting laws can ask for it. Microsoft's 2025 supplier instructions use independent assurance as one option for total-company and service-level GHG emissions. For entities required to prepare a sustainability report under Chapter 2M of Australia's Corporations Act, ASSA 5010 requires a review of specified first-year disclosures, review of all disclosures in years two and three, and an audit of all disclosures from year four.

How does sustainability assurance work?

Set the scope before testing: entity, period, disclosures, reporting rules and assurance level. The provider selects records, checks calculations and controls, investigates differences and signs a conclusion. If a request also mentions consultant support, compare consultant letters with independent assurance before choosing the deliverable.

What mistakes should you avoid?

  • Calling advice from the disclosure preparer independent assurance.
  • Not naming the entity, period, metrics or reporting rules.
  • Claiming the full report was assured when the conclusion names only selected disclosures.

Is sustainability assurance limited to GHG emissions?

No. It can cover environmental, social or governance information. The signed conclusion must identify the information actually tested.

Can one assurance report cover only part of a sustainability report?

Yes. Read the scope and conclusion before sending it. Unlisted metrics, sites, periods and forward-looking statements are not covered merely because they appear beside assured information.

Example

Hypothetical Thailand example: Suppose an electronics contract manufacturer reports three 2026 metrics: 18,400 megawatt-hours (MWh) of purchased electricity, 126,000 cubic metres of water withdrawal and four lost-time injuries. Its customer asks for limited assurance over the electricity and water metrics only.

The provider's report covers the purchased-electricity and water-withdrawal metrics for 2026. It does not cover the lost-time injury figure, other metrics, another period or the rest of the report.

Where it comes up

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Sources

Last verified 2026-08-20

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Sustainability assurance Definition | Keslio