Sustainability Reporting Assurance

Sustainability reporting assurance is the independent third-party verification that a company’s sustainability disclosures are free from material misstatement and prepared in accordance with the applicable reporting standards. Under the CSRD (EU) 2022/2464, mandatory limited assurance of sustainability statements is required from the first year of reporting; reasonable assurance (the higher standard) is expected to become required from 2028 onwards for EU reporters. The Omnibus I provisional agreement clarifies that limited assurance applies and sets maximum financial penalties for supervisory authorities at 3% of the company’s net worldwide turnover.

CSRD (EU) 2022/2464, Article 26a; International Standard on Assurance Engagements (ISAE) 3000 (limited assurance); European Commission guidance on assurance standards (2024); Omnibus I provisional agreement (December 2025).

CSRD-scoped companies must engage an accredited auditor or assurance provider for sustainability statement limited assurance from year one of reporting. Assurance providers will verify: materiality assessment process; data collection systems; completeness of disclosures; and compliance with ESRS. Companies should involve their assurance provider early in the sustainability reporting process to identify data quality gaps. Limited assurance is materially less onerous than financial statement audits but requires documented, evidence-supported disclosures.