More than two thirds (69) of the FTSE 100 made restatements on their sustainability metrics in 2025, rising for the third consecutive year.

Research from Deloitte shows a significant increase from the 46 companies last, and most notably, the number of companies disclosing multiple prior-year adjustments (PYA)s tripled to 51 companies (17 companies last year).

Now in its third year, the latest analysis looked at climate and sustainability disclosures in the most recently published annual reports as of 31 December 2025. The drivers for PYAs have also evolved from previous years, with a 23 per cent decrease in error-driven PYAs.


Steve Farrell, partner and head of sustainability assurance at Deloitte UK, said: “With adjustments increasing for the third year in a row, this recent data shows us they have become a core feature of FTSE 100 climate reporting. The decrease in error-driven misstatements indicates improvement in reporting quality, particularly as restatements due to changes in methodology, business structure and other factors, have increased significantly.”

Of the restatements made, the majority (65 per cent) related to greenhouse gas (GHG) emissions, with the remainder comprised of a variety of other sustainability topics (including waste, water, D&I, and health & safety).

Alongside this, 86 FTSE 100 companies publicly stated that they obtained assurance over sustainability metrics in 2025, increasing from 84 the previous year and 74 in 2023. ISAE 3000 continues to be the dominant assurance standard, with 79 per cent limited or reasonable assurance under ISAE 3000.

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