As ESG, climate and sustainability reporting expectations continue to grow, organizations need confidence that sustainability information is accurate, reliable, and decision ready. Independent assurance strengthens credibility, supports compliance, and builds stakeholder trust.
ERM CVS delivers independent ESG and sustainability assurance services worldwide, helping organizations improve data quality, strengthen reporting processes, and prepare for assurance with confidence.
ESG, climate, and sustainability disclosures assurance is the independent, third-party evaluation of sustainability information intended for public disclosure.
This includes ESG metrics, climate data, sustainability disclosures, claims, methodologies, and reporting processes. Assurance providers assess whether reported information is accurate, complete, reliable, and prepared in line with the applicable reporting criteria and assurance standards.
Similar to a financial audit, sustainability assurance involves reviewing reporting processes, internal controls, supporting evidence, and data management systems before issuing an independent assurance conclusion.
Sustainability disclosures increasingly influence investment, procurement, regulatory, and business decisions. Independent assurance helps organizations improve reporting quality, strengthen stakeholder confidence, reduce reporting risk, and demonstrate that sustainability information can be trusted. As regulatory reporting requirements continue to expand, assurance is rapidly becoming an expectation rather than a differentiator.
Increase confidence in sustainability and climate disclosures with assurance backed by more than 30 years of experience.
Access independent sustainability assurance delivered by global experts in ESG, auditing, and reporting.
Navigate complex reporting and assurance requirements through our experts. across leading voluntary and regulatory frameworks.
Stay ahead of evolving expectations through a partner that contributes to the development of international assurance standards.
Increased confidence in sustainability disclosures
Meet expanding regulatory and assurance requirements
Strengthen governance, reporting controls and decision-making
Support informed business and investment decisions
Improve supply chain transparency and accountability
Meet stakeholder and regulatory expectations
Improve ESG data quality and reliability
Reduced reputational risk with greater trust in sustainability claims
Organizations increasingly seek assurance to strengthen stakeholder confidence, improve reporting quality, support regulatory compliance, and demonstrate the credibility of sustainability disclosures and claims. Regulatory requirements are also driving the requirement for mandated assurance with regulation such as CSRD, and the emerging North America legislations such as California Climate Bill SB 253.
Assurance engagements are typically conducted in accordance with internationally recognized assurance standards. Today, many sustainability assurance engagements are performed under ISAE 3000, while ISSA 5000 is emerging as the dedicated global standard for sustainability assurance. ISSA 5000 becomes effective for assurance engagements from December 2026 and is expected to be widely adopted for 2027 sustainability disclosures.
ISAE 3000 - A globally recognised assurance standard for evaluating the reliability of non-financial information and disclosures.
ISSA 5000 - The new global sustainability assurance standard, designed specifically for ESG and sustainability disclosures and stakeholder reporting expectations.
AA1000 Assurance Standard - A stakeholder-focused assurance standard based on the principles of inclusivity, materiality, responsiveness, and impact.
ESG, climate, and sustainability disclosure assurance is performed against the reporting frameworks used to prepare and disclose sustainability information, including the EU's Corporate Sustainability Reporting Directive (CSRD), The International Sustainability Standards Board (ISSB), the Global Reporting Initiative (GRI), IFRS Sustainability Disclosure Standards (IFRS S1 and IFRS S2),Sustainability Accounting Standards Board (SASB), Task Force on Climate-Related Financial Disclosures (TFCD), Voluntary Sustainability Reporting Standard for SMEs (VSME), Taskforce on Nature-related Financial Disclosures (TNFD) and many more. CSRD, ISSB and GRI are the most prominent frameworks.
Not necessarily. ESG assurance can be provided by qualified independent assurance providers with appropriate sustainability, climate, technical, and assurance expertise, unless a financial auditor is required by regulations as determined in each jurisdiction. The most important consideration is selecting a provider that meets the applicable regulatory, assurance standard, and stakeholder requirements for your reporting obligations. In ESG and sustainability reporting, technical expertise enables assurance providers to deliver deeper insights, strengthen reporting quality, improve data reliability, and create greater business value beyond compliance.
Both limited assurance and reasonable assurance provide confidence over your reported information. For limited and reasonable assurance, you test the same things, and the difference is in the amount and depth of testing the assurance provider needs to reach a conclusion. The assurance report language issued by the assurance provider will also be different, so that the stakeholders that use your report will know which level of assurance you’re received. A report for a limited assurance engagement will say ‘nothing has come to our attention to make us believe the information as presented isn’t correct. While the reasonable assurance report will say that the information as presented is correct in all material aspects.
Following the 2026 Omnibus revisions, mandatory sustainability reporting generally applies to large companies with more than 1,000 employees and €450 million in annual turnover, including certain non-EU companies with significant operations in the European Union. Organizations within scope must report sustainability information in accordance with the European Sustainability Reporting Standards (ESRS) and obtain independent assurance over reported disclosures.
Note: CSRD requirements continue to evolve and application may vary depending on company structure, listing status, and EU Member State implementation
Double materiality is a core requirement of CSRD and helps determine which sustainability topics an organization must report under the European Sustainability Reporting Standards (ESRS).
A topic is considered material if it is significant from either perspective, or both. The results of the double materiality assessment determine the scope and content of CSRD disclosures.
As long as there is a reporting criteria, assurance can cover complete sustainability reports, ESG metrics, climate and GHG emissions data, biodiversity and nature disclosures, human rights information, supply chain disclosures, sustainability targets, and selected ESG performance indicators.
Timing depends on reporting scope, data availability, organizational readiness, and required assurance level. A scoping discussion can help determine expected timelines for your specific needs.
This depends on your drivers and organizations can proceed directly to an assurance engagement if they believe their reporting processes, controls, and supporting evidence are sufficiently mature. However, many organizations choose to undertake an assurance readiness review or pre-assurance assessment first to identify gaps, reduce risk, and improve the efficiency and the success of the subsequent assurance process.
Independent assurance provides objective scrutiny of disclosures, data, methodologies, and claims, helping organizations support statements with evidence and improve transparency and credibility.
