31 July, 2026

New analysis from Deloitte shows that 69% of FTSE 100 companies made prior-year adjustments to sustainability metrics in 2025, up from 46% the year before. At first glance, that might sound concerning, but a closer look suggests many of these changes reflect improvements in how companies collect, calculate and report sustainability data. Adjustments driven by reporting errors actually fell, while revisions linked to improved methodologies, better data and organisational changes increased.

Much of the adjustments were made on Scope 3 emissions, which remains one of the biggest challenges in sustainability reporting. Three quarters of companies that restated greenhouse gas data made changes to their Scope 3 figures. Unsurprising, as Scope 3 covers emissions across the wider value chain, from suppliers and logistics to the use of products and services. It is often the largest part of a company’s carbon footprint, but almost always also the hardest to measure. Data is drawn from multiple sources, different countries and displays varying levels of reporting maturity, making accuracy an ongoing challenge.

The challenges around data collection and quality are something we see every day in the work we do with our clients. Sustainability reporting is still maturing, and organisations are often working with information that is incomplete, evolving or dependent on data from third parties. As systems improve and new information becomes available, restatements should be expected. In many cases, they are a sign that organisations are taking reporting seriously and working to improve the quality of what they disclose.

Of course, revisions should never be used to selectively present a better story. Transparency matters, and any changes must be clearly explained. But when restatements reflect better data, stronger methodologies or a more complete understanding of impacts, they should be welcomed. Better data leads to better decisions, stronger year-on-year comparisons and greater confidence in sustainability reporting. There is still work to do, particularly on Scope 3, but the direction of travel is positive. As reporting standards and data quality continue to improve, organisations and their stakeholders will benefit from a clearer and more reliable picture of environmental impact.

By Tulika Agarwal