News 17/02/26

4 guidelines for audit firms to contribute to a robust approach CSRD assurance

In 2025, PIE audit firms provided assurance according to the Corporate Sustainability Reporting Directive (CSRD) for the first time. The AFM observes that they have taken substantial steps. To support the (further) development of a robust approach to CSRD assurance, we present four key pillars. CSRD assurance contributes to reliable, understandable and consistent sustainability reporting, helping investors and society to make well-informed decisions.

In short

PIE audit firms provide CSRD assurance for the first time
Substantial progress has been made
AFM presents four pillars for a robust approach to CSRD assurance
Relevant for both PIE and non-PIE audit firms

PIE audit firms provide CSRD assurance for the first time

Although the CSRD has not yet been implemented in Dutch law, almost all large listed companies voluntarily prepared their sustainability reports for the 2024 reporting year in accordance with the CSRD. These reports are important, as they provide insight into a company’s impact on the environment, people and society. In 2025, the six large PIE audit firms provided assurance on these sustainability reports for the first time. The aim of this assurance is to provide reliability, understandability and consistency of the sustainability information.

Substantial progress has been made

Since our 2023 exploratory review - conducted in preparation for the first year of CSRD assurance in 2025 - audit firms have made substantial progress. We observe that they have further developed their quality control systems, particularly regarding capacity and expertise.

AFM presents four pillars for a robust approach to CSRD assurance

To safeguard the quality of CSRD assurance, the AFM emphasises four key pillars:

Maintain a robust quality control system for CSRD assurance

Ensure a competent assurance team and effective project management

Understand the client and its processes for an appropriate assurance plan

Tailor the procedures in the execution phase to the assessed assurance risks and assurance materiality

Relevant for both PIE and non-PIE audit firms

We encourage PIE audit firms to continue their positive development towards a robust assurance approach, using the insights and examples included in our report. These examples are intended to inspire the sector to (continue) developing a sound approach to CSRD assurance engagements.

From the 2027 reporting year onwards, the CSRD will also apply to large companies with more than 1,000 employees and turnover exceeding €450 million. Assurance engagements for these companies may be performed not only by PIE audit firms but also by audit firms with a regular licence. Because CSRD assurance is new and fundamentally different from financial assurance - due to its focus on non-financial information, value chain and the more frequent use of estimates - this requires different expertise. This report supports audit firms in making a strategic decision on whether to provide CSRD assurance and helps them to prepare effectively.