Sustainability reporting is accelerating fast – and assurance is becoming essential to build trust in sustainability information and impact on decision making process. Learn how early engagement and robust processes can turn assurance from a compliance task into a source of value.
Today, the need for precise sustainability data is more important than ever to drive informed business decisions. Find out how to streamline reporting processes, avoid common pitfalls, and build a foundation that supports trustworthy, decision-ready sustainability information.
Sustainability reporting is entering a new phase. As expectations from investors, and internal stakeholders continue to rise, organisations need to demonstrate not only transparency but credibility. Discover the full insights in PwC’s Global Sustainability Reporting Survey 2025. Assurance plays a central role in this shift: it strengthens trust in non-financial information and helps organisations build mature, reliable reporting processes. Yet many companies still perceive sustainability assurance as a complex and resource-intensive exercise that sits outside established financial reporting practices.
Why assurance matters now
Even though sustainability assurance is still limited in scope for most companies, addressing the topic can no longer be postponed. Stakeholder expectations are rising, and non-financial data will be subject to increasing scrutiny. Organisations that start early position themselves to manage this transition confidently and efficiently.
Assurance enhances the credibility of sustainability disclosures, strengthening trust at a time when this information is becoming central to strategic decision-making and external communication. Early and ongoing collaboration with auditors helps teams understand expectations, anticipate common pitfalls, and build the capabilities needed for high-quality reporting.
At the same time, assurance offers value far beyond compliance: it supports more efficient processes, improves governance, and helps embed sustainability into the wider organisation.
The challenges – and where companies get stuck
What we consistently hear in client conversations is that organisations face a number of recurring challenges when preparing for sustainability assurance:
Interpretations of EFRAG’s “shall/may” requirements – EFRAG being the European body that develops the European Sustainability Reporting Standards (ESRS) – often differ, particularly for qualitative disclosures, creating uncertainty about what needs to be reported and how. In parallel, synergies between financial and sustainability reporting teams remain limited in many organisations, resulting in fragmented processes and inconsistent data flows.
We also see that sustainability assurance is sometimes perceived as a “box-ticking exercise”, which can reduce internal engagement and make it harder to position sustainability reporting as a strategic activity. Preparing for assurance requires time and resources, and many teams underestimate the level of documentation, coordination, and governance needed to support credible reporting.
Boards are increasingly requesting higher levels of assurance for complex topics – for example Scope 3 greenhouse gas emissions – even though processes and controls may not yet be ready for deeper scrutiny. Internal audit functions are also not yet fully integrated into non-financial reporting reviews, leaving efficiency gains untapped.
As a result, organisations often face inefficiencies, repeated iterations, and reporting processes that feel more complex than necessary.
Building an assurance-ready reporting process
A few targeted actions can help organisations streamline preparation, improve data quality, and make their assurance process more effective.
1. Align non-financial and financial reporting processes
The most effective organisations treat sustainability reporting as an extension of financial reporting. This means aligning controls, systems, roles, and review cycles. Finance and non-finance teams working together as a single unit significantly reduce complexity and increase data reliability.
2. Start preparation for assurance early – long before the publication deadline
Experience shows: the earlier auditors are involved, the smoother the process. Early engagement enables readiness assessments, gap analysis, prioritisation, and pre-assurance of critical datapoints.
3. Focus on what is material
With extensive data requirements, it is easy to lose sight of what really matters. Prioritising material topics and aligning disclosures with the organisation’s strategy ensures that assurance efforts support meaningful reporting rather than simply covering what is easiest to audit.
4. Use existing structures instead of reinventing the process
Many sustainability processes can leverage established financial reporting mechanisms. The hurdle may not be as high as perceived – the foundation often already exists.
5. Integrate internal audit
More mature organisations are beginning to incorporate sustainability reporting into their internal audit plans. Over time, external auditors will increasingly rely on this work, reducing duplication of effort.
6. Avoid common pitfalls
Typical pitfalls include late preparation, unclear ownership, insufficient documentation, limited cross-functional collaboration, and a lack of early dialogue with auditors. Addressing these areas early can significantly reduce later iterations and stress.
What this means for organisations in 2026
Sustainability reporting is evolving at pace. Requirements that took decades to establish in financial reporting must now be built for non-financial information within only a few years. The organisations that invest early in clear processes, controls, and responsibilities will be best positioned to meet expectations efficiently and capture the business value of reliable sustainability data.
Early engagement with assurance providers helps organisations clarify expectations, strengthen competencies, and avoid costly rework. Auditors bring valuable perspectives, support teams with training, and help ensure that material information is prepared in a robust and decision-ready way.
Act with confidence – and unlock business value through robust non-financial reporting processes, strengthened by external assurance.
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Oksana Zinchenko