Audit of sustainability reporting

The Corporate Sustainability Reporting Directive (CSRD) has fundamentally transformed sustainability reporting in the European Union. In Austria, the CSRD was transposed into national law through the Sustainability Reporting Act (NaBeG), Federal Law Gazette I No. 6/2026. The NaBeG has been in force since February 2026 and replaces the previous Sustainability and Diversity Improvement Act (NaDiVeG) as the central legal basis for sustainability reporting.
The new regulations focus mandatory sustainability reporting on particularly large companies. Under current Austrian law, the scope will generally cover companies with more than 1,000 employees and net turnover in excess of EUR 450 million. First-time application for the newly covered companies is scheduled for financial years from 2027 onwards. Capital market-oriented SMEs are no longer mandatorily included within the scope of the CSRD.

The NaBeG contains transitional provisions for companies that were already subject to reporting requirements under European non-financial reporting regulations. At the same time, some of the simplifications introduced by the European Omnibus I package have already been incorporated into Austrian law. This necessitates a nuanced assessment of the relevant reporting obligations and the financial year.

Sustainability reporting is subject to a mandatory external audit. The NaBeG expressly provides for the audit of sustainability reporting; audits must comply with the relevant international auditing standards.

An audit of sustainability reporting provides additional assurance regarding the relevance, completeness and reliability of the published sustainability information. At the same time, it helps to improve the quality of the underlying data, processes and control systems.
We support companies both in preparing for the external audit and in carrying out assurance engagements. In doing so, we consider not only the published key figures but also how they are derived – from data collection through internal processes and controls right through to reporting.

The International Standard on Assurance Engagements (ISAE) 3000 (Revised) is particularly relevant for assurance engagements relating to sustainability information. The current statutory audit is generally carried out on a limited assurance basis.

Reliable sustainability reporting builds trust among investors, business partners, financial institutions, employees and other stakeholders. At the same time, structured preparation for an audit helps to identify and rectify weaknesses in data, processes and controls at an early stage.

We combine our experience in Audit & Assurance with comprehensive sustainability expertise. This enables us to assess both the regulatory requirements for sustainability reporting and the underlying data, processes and control systems in a holistic manner.

Our interdisciplinary approach supports you in ensuring your sustainability reporting is reliable, transparent and audit-ready – regardless of whether you are already subject to statutory reporting requirements or are preparing for future or voluntary requirements.