Sustainability reporting, audit and assurance

Sustainability reporting is critical for effective governance, risk management and stakeholder trust. Whether driven by regulation or market expectations, organisations must deliver reliable, decision-useful and audit-ready data.

At Forvis Mazars, we simplify sustainability requirements into clear, trusted information that supports confident decision-making. We combine sustainability expertise with audit and assurance skills so organisations can meet reporting requirements, strengthen internal controls and build confidence in their disclosures.

Our approach

We take a structured, end-to-end approach to sustainability reporting and assurance, from initial scoping through to audit readiness.

Our approach focuses on:

• Understanding your reporting obligations – including CSRD, ESRS and VSME requirements
• Designing robust processes and controls – to ensure consistent, high-quality data
• Embedding governance and accountability – across sustainability reporting frameworks
• Preparing for assurance – aligning systems and documentation with audit expectations

We combine sustainability expertise with audit capability to deliver reporting that is both technically robust and assurance-ready.

Our approach includes ESG internal audit, providing independent validation of data quality, controls and governance before external assurance. Developed in collaboration with a leading Irish university, this bridges the gap between sustainability advisory and formal audit, giving leadership teams confidence in their sustainability data.

We help organisations move beyond compliance to build credible, decision-useful reporting frameworks that support strategy, risk management and stakeholder trust.

The Irish reporting landscape

Sustainability reporting requirements in Ireland continue to evolve.

• The Corporate Sustainability Reporting Directive (CSRD) will apply to approximately 250 Irish companies, with Irish transposition expected by September 2027
• For organisations outside the scope, the VSME standard offers a proportionate voluntary framework

For many organisations, sustainability reporting is now driven not only by regulation, but also by customer requirements, bank lending criteria and public procurement expectations.

High-quality reporting is essential for credibility and for a strong competitive position.

Our sustainability reporting, audit and assurance services

We support organisations throughout their sustainability reporting journey, from first-time reporters to those preparing for external assurance. Our approach combines regulatory expertise, robust data processes and practical implementation support.

Sustainability reporting

We help organisations deliver high-quality, decision-useful sustainability disclosures aligned with evolving regulatory and stakeholder expectations.

Our sustainability reporting services include:

• CSRD and ESRS reporting support
• Voluntary reporting (VSME, GRI, ISSB / IFRS S1 & S2, TCFD, CDP, SASB)
• Double materiality assessments
• ESG data management processes and tools
• ESG content drafting and refinement
• Greenwashing risk mitigation
• Digital reporting and XBRL solutions

Internal audit & ESG controls

Reliable reporting depends on effective governance, systems and internal controls. We help organisations embed ESG into their internal control environment.

Our internal audit and controls services include:

• ESG governance and control framework design
• ESG data controls and systems assurance
• Readiness and gap assessments
• ESG process and IT system reviews
• Supply chain ESG assurance (e.g. human rights, environmental risks)
• Internal audit support for ESG-related risks

Audit and assurance

Independent assurance enhances the credibility of sustainability disclosures, supports regulatory compliance and builds stakeholder trust.

We provide:

• Regulatory sustainability assurance: ESRS assurance under CSRD and other jurisdictional requirements (e.g. UK SRS, ASRS).
• Voluntary assurance: Assurance over disclosures aligned with ESRS, VSME, ISSB, GRI, SASB, CDP and GHG frameworks.
• GHG emissions assurance: Limited or reasonable assurance over Scope 1, 2 and 3 emissions under ISAE 3000 and ISAE 3410.
• KPI and target assurance: Verification of sustainability metrics, including net-zero targets and performance indicators.
• Sustainable finance assurance: Assurance over green and sustainability-linked loans, bonds and transition finance instruments.
• Pre-assurance readiness: Preparing organisations for assurance through data testing, control reviews and documentation.

Contact us

Whether you are preparing for CSRD, adopting VSME or strengthening your internal controls, we can support you. Contact our team to build sustainability reporting that is audit-ready from day one.