The role of the ESG auditor: who they are, what they do, why they are mandatory

The ESG auditor, or sustainability auditor, is a professional tasked with verifying the compliance of non-financial information that companies must report according to the Corporate Sustainability Reporting Directive (CSRD). This role was created to ensure the accuracy of environmental, social, and governance (ESG) data reported by companies in sustainability reports. His role is similar to that of a statutory auditor, but applied to the non-financial field. He must guarantee that the ESG report is prepared in accordance with the European ESRS (European Sustainability Reporting Standards), thus providing stakeholders (investors, customers, institutions) with a reliable picture of the company's commitment to sustainability.

The ESG auditor performs an assurance activity on non-financial information published by companies, which can be a limited or reasonable review of the data contained in the sustainability report. It verifies compliance with the criteria set by the ESRS standards and the requirements set by the CSRD regulation. Its main activities include: collecting documentary evidence, analyzing business processes related to ESG impacts, identifying greenwashing risks, and drafting a compliance opinion. Essentially, it acts as a guarantor of the integrity of sustainability reporting, helping to increase market trust and make the environmental, social, and governance strategies adopted by companies more credible.

Starting in 2024, with concrete effects from the 2025 budget, the ESG auditor becomes mandatory for large companies and listed companies, as required by the CSRD. In Italy, the transposition of the directive is underway, but the Decreto Milleproroghe 2024 has introduced a time window and a waiver of penalties for the first year. In practice, companies subject to the obligation can take advantage of a transition period, during which a reduced penalty regime is provided. Then, from 2026 the audits will become binding. The mandatory ESG auditor represents a turning point for non-financial reporting, laying the foundations for transparent and responsible corporate governance.

The sustainability auditor must possess multidisciplinary skills that combine knowledge of auditing techniques with a deep familiarity with ESG topics and European ESRS standards. They are often statutory auditors, accounting experts, or accredited professionals who have completed specific training courses in the field of sustainability. A solid preparation in regulatory, managerial, and environmental matters is required, as well as the ability to analyze qualitative and quantitative data from the sustainability report. The professional must also demonstrate independence, integrity, and objectivity, essential qualities to ensure the credibility of information and prevent conflicts of interest in the reporting process.

The assurance process strengthens stakeholder trust and makes it easier to access sustainable investments and ESG-linked financing. Furthermore, it helps improve the company's image, reduces reputational risks, and promotes real change in business models. The review of non-financial information helps companies identify critical areas, monitor progress and define corrective actions. The ESG auditor is an indispensable ally for effectively integrating ESG objectives into the long-term business strategy.

This article was created within the framework of the project "Biodiversity services EU expansion" (CUP: E43D22000480009) under the Regione Lombardia call "PR FESR 2021-2027 – LINEA INTERNAZIONALIZZAZIONE 21-27", aimed at supporting the internationalization of Italian companies. 3Bee is the naturetech company that develops innovative technologies for monitoring, protecting, and regenerating biodiversity, supporting companies in defining personalized climate strategies based on the analysis of their impacts and dependencies on nature. With a consolidated portfolio in Italy, Germany, and France and significant partnerships, 3Bee continues its expansion in international markets to create a concrete impact through technology.