A Complete Guide to ESG Reporting for Auditors and Finance Teams

What do auditors need to know about ESG reporting? (short answer) ESG reporting is becoming part of audit work due to regulatory pressure, investor demand, and the growing use of external assurance. ESG disclosures often rely on non-financial data, estimates, and evolving frameworks, which increases the importance of clear documentation, traceability, and professional judgment in audit engagements. 

This guide exists to make that shift easier to navigate. It looks at how ESG reporting is evolving, what auditors are being asked to evaluate today, and where judgment, documentation, and consistency matter most.

TL;DR: Key takeaways

ESG reporting is now part of many audit engagements. Most large organizations publish ESG information, and external assurance is becoming more common. At the same time, auditors face practical challenges related to data quality, regulatory interpretation, and evidence consistency.

Key takeaways

• ESG reporting is now widely adopted among large organizations
• External assurance over ESG information is becoming standard practice
• Regulatory pressure is driving more structured and auditable ESG disclosures
• Data complexity remains the main challenge in ESG audits
• Human judgment remains essential, even as technology supports audit work

Why is ESG reporting now part of audit engagements?

ESG covers a broad range of criteria:  

• Environmental: A company's impact on the planet, focusing on issues like carbon emissions, resource usage, waste management, and climate change policies.

• Social: How companies manage relationships with employees, suppliers, customers, and communities. Key topics include labor practices, diversity and inclusion, human rights, as well as community engagement.

• Governance: Practices, controls, and procedures a company adopts to govern itself, make effective decisions, comply with the law, and meet the needs of external stakeholders. This includes board composition, executive compensation, and shareholder rights.

ESG reports should paint a transparent and coherent picture of these core elements. Transparency is crucial for auditors to verify the accuracy and reliability of the data, enabling those using the report to fully grasp a company's long-term value, environmental footprint, and commitment to sustainability.

Investor demands and societal impact

Investors from large asset managers like BlackRock to smaller individual investors are increasingly seeking ESG data to inform their decisions. They recognize that companies with robust ESG practices tend to demonstrate better risk management and financial performance, an area where auditors play a vital role.

Reliable ESG data i.e. ESG data verified by auditors, serves societal interests by promoting corporate accountability, improving societal well-being, and supporting a more sustainable future. ESG reporting is a crucial tool for investors to evaluate a company's ethical practices and risk exposure, shaping their investment decisions.

Commercial differentiator

ESG performance increasingly influences commercial decisions. Customers, partners, and public-sector buyers are more likely to work with organizations that can demonstrate credible ESG practices. In some markets, providing ESG information is no longer optional, but a condition for doing business.

These expectations extend beyond large organizations. As ESG requirements move into supply chains, smaller and medium-sized businesses are increasingly asked to provide ESG data to customers that are subject to regulatory reporting. Even where formal reporting obligations do not apply, the absence of ESG information can limit access to key contracts.

For many organizations, investing in ESG processes and reporting is becoming part of maintaining competitiveness. As ESG reporting becomes more embedded in commercial relationships, auditors are likely to encounter ESG information across a wider range of engagements.

The ESG reporting landscape auditors are navigating

ESG reporting covers environmental, social, and governance topics. These areas often rely on data that sits outside finance systems and is owned by different teams.

Unlike financial reporting, ESG data may involve estimates, narratives, third-party inputs, and evolving definitions. This makes planning, testing, and documentation more complex for auditors.

Understanding where data originates and how it is compiled is a key part of ESG audit work.

How is regulation changing ESG reporting requirements for auditors?

Regulatory frameworks are moving ESG reporting toward structured and auditable disclosures.

For auditors, this signals a clear direction of travel. ESG reporting is moving closer to financial reporting standards in terms of structure and scrutiny.

ESG frameworks auditors commonly encounter

Auditors often review ESG disclosures prepared under more than one framework. Each framework has a different purpose, scope, and level of prescriptiveness. Understanding these differences is important for audit planning, scoping, and documentation.  

CSRD and ESRS

The Corporate Sustainability Reporting Directive and the European Sustainability Reporting Standards apply to a growing number of companies operating in or connected to the EU.

From an audit perspective, CSRD and ESRS matter because they:

• Introduce legally binding reporting requirements
• Require structured, standardized disclosures
• Apply the concept of double materiality
• Are designed to support future assurance, including a path toward reasonable assurance

Auditors working with CSRD-scoped entities need to assess how management has interpreted ESRS requirements, how data is collected across the organization, and whether disclosures are complete and consistent with the standard.

GRI

The Global Reporting Initiative is one of the most widely used ESG frameworks globally. It focuses on impact reporting across environmental, social, and governance topics.

For auditors, GRI is relevant because:

• It allows significant flexibility in topic selection and disclosure depth
• Disclosures are often qualitative and narrative in nature
• Definitions and metrics can vary by organization

This flexibility increases the need for clear documentation of scope, assumptions, and management judgment when reviewing GRI-based disclosures.

SASB

The Sustainability Accounting Standards Board framework focuses on financially material ESG topics by industry.

Auditors often encounter SASB when:

• ESG disclosures are integrated into financial filings
• Companies aim to link sustainability topics to financial performance
• Industry-specific metrics are emphasized

SASB’s industry focus can support comparability, but it also requires auditors to understand how management determined financial materiality and applied industry guidance.

TCFD

The Task Force on Climate-related Financial Disclosures framework focuses on climate risk, governance, strategy, risk management, and metrics.

From an audit standpoint, TCFD disclosures often involve:

• Forward-looking statements
• Scenario analysis and assumptions
• Links between climate risk and financial reporting

These elements increase the importance of reviewing assumptions, consistency with other disclosures, and alignment with risk management processes.

ISSB

The International Sustainability Standards Board aims to create a global baseline for sustainability reporting focused on enterprise value.

Auditors should pay attention to ISSB because:

• It is increasingly referenced by regulators and standard setters
• It aligns sustainability disclosures more closely with financial reporting concepts
• It is designed with assurance in mind

As ISSB adoption grows, auditors may see greater convergence between sustainability and financial reporting expectations.

Why framework complexity matters for auditors

When multiple frameworks are used together, disclosures may overlap, diverge, or rely on different definitions for similar concepts. This increases the risk of inconsistency and omission.

For auditors, this makes:

• Clear audit planning essential
• Documentation of scope and framework selection critical
• Traceability between disclosures and underlying data more important

Understanding the intent and structure of each framework helps auditors assess ESG disclosures with clarity and consistency.

The real challenge of ESG reporting in practice is execution

While ESG reporting is widespread, execution remains difficult.

For auditors, this complexity often appears as inconsistent definitions, incomplete evidence, and difficulty assessing completeness. These challenges increase the importance of structured testing and professional judgment.

The evolving role of the auditor in ESG assurance

In practice, this means auditors are expected to:

• Apply consistent methodology, even where assurance remains limited
• Clearly define and document scope, assumptions, and procedures
• Review large volumes of ESG evidence across multiple data sources
• Communicate conclusions in a way that supports transparency and trust

To support this work, many audit teams use audit automation to manage ESG evidence and documentation more effectively. Tools like DataSnipper help by:

• Linking ESG figures and disclosures directly back to source documents in Excel
• Maintaining traceability across working papers and reports
• Reducing manual reconciliation while preserving auditor judgment

This approach allows auditors to handle growing ESG workloads without compromising control or audit quality. Here is a detailed video of ESG procedures with audit automation.

How technology can support ESG audits

Which parts of ESG audits still require human judgment?

Technology can support ESG audits, but it does not replace audit responsibility. Auditors continue to make key decisions, including:

These responsibilities are consistent across professional guidance and industry research.

For a deeper dive with ESG experts, check out our dedicated webinar which is looking at collecting and interpreting ESG Data.

Deep Dive Webinar with ESG Experts

FAQ auditors ask about ESG reporting

When I audit an organization, how do I determine whether ESG information is in scope?

ESG information is in scope when it is included in regulatory filings, annual reports, sustainability reports, or referenced in investor communications. Scope is also influenced by regulatory requirements, such as CSRD, and by whether management has committed publicly to ESG targets or disclosures.

When reviewing ESG disclosures, what level of assurance is typically expected?

Most organizations currently obtain limited assurance over selected ESG disclosures. However, regulatory trends and market expectations indicate a gradual move toward broader and more rigorous assurance, particularly for environmental and climate-related data.

When an organization reports under multiple ESG frameworks, how should auditors approach consistency?

Auditors should understand the intent and scope of each framework used and assess whether overlapping disclosures are consistent in definitions, metrics, and assumptions. Clear documentation of which framework applies to which disclosures is essential.

When auditing ESG data, where do the biggest data quality issues usually arise?

Data quality issues most often arise from manual data collection, inconsistent definitions, reliance on third-party data, and lack of standardized controls outside finance systems. These issues affect completeness, accuracy, and traceability.

When ESG disclosures include forward-looking statements, how should auditors assess them?

Auditors focus on whether assumptions are reasonable, consistently applied, and aligned with other disclosures. Forward-looking ESG information requires careful review of methodology, governance, and supporting documentation rather than verification of outcomes.

When does ESG reporting increase the risk of greenwashing?

Greenwashing risk increases when disclosures lack supporting evidence, use vague language, or selectively present favorable information. Auditors assess this risk by reviewing consistency, completeness, and alignment with underlying data and controls.

When planning an ESG audit, how should materiality be assessed?

Materiality assessments consider regulatory requirements, stakeholder impact, business context, and the organization’s own risk assessments. In frameworks such as CSRD, double materiality requires evaluating both financial and impact perspectives.

When technology is used in ESG audits, what remains the auditor’s responsibility?

Auditors remain responsible for materiality decisions, risk assessment, interpretation of results, evaluation of exceptions, and communication of conclusions. Technology supports data handling and traceability but does not replace professional judgment.

When ESG assurance is limited, how do auditors demonstrate rigor?

Rigor is demonstrated through clear scoping, documented procedures, transparent assumptions, and traceable evidence. Limited assurance still requires disciplined methodology and professional skepticism.

When should auditors expect ESG reporting requirements to change again?

ESG reporting requirements are evolving rapidly due to regulatory developments and standard-setter activity. Auditors should expect ongoing changes in scope, structure, and assurance expectations, particularly in relation to climate and social disclosures.

When ESG data sits outside finance teams, how can auditors maintain control?

Auditors maintain control through clear data ownership mapping, defined evidence requirements, and traceability between disclosures and source documentation. Cross-functional coordination is a key part of ESG audit planning.