Lessons learned from 1,000 CSRD reports

Recent changes agreed by European Union members slashed the number of companies subject to the bloc’s Corporate Sustainability Reporting Directive (CSRD) rules, and pushed back the deadline for submitting reports. But many large companies had already started filing CSRD reports, as the earlier version of the directive required.

Researchers across the continent have now collected more than 1,100 of those reports at the free-to-access Sustainability Reporting Navigator. Trellis asked Maximilian Müller, a financial accounting expert at the University of Cologne and member of the navigator team, what he and colleagues have learned from the reports submitted so far.

These are not your typical sustainability reports

Sustainability reporting is still something of a Wild West. While there are generally agreed-upon rules that most companies follow, such as emissions accounting guidelines from the Greenhouse Gas Protocol, they are mostly voluntary. And beyond those rules, companies have leeway to create and prioritize particular metrics — emissions intensity, for example — to suit their needs.

CSRD, by contrast, is a compliance regime, which means there are consequences for breaking the rules. Member states are in the process of setting their own punishments, and some are considerable. In Germany, for example, the government has mooted fines of up to €10 million.

It’s no surprise then that CSRD reports have a different flavor. “These kind of sustainability reports are less PR, more 10-K-like,” said Müller. In practice, that means they are longer — 30 percent so when compared to earlier reports from the same company, he estimates — and more negative in tone.

As required by the directive, companies also have to obtain what’s known as “limited assurance” for their reports. Think of this as a lighter-touch version of the “reasonable assurance” required for financial reporting, in which the third-party assurer checks only for signs of problems in the data, but stops short of confirming that the numbers are accurate. In the reports filed so far, companies are overwhelmingly using the Big Four accounting firms — KPMG, PwC, EY and Deloitte — for this service.

Better benchmarking, less storytelling

The shift toward a compliance approach brings costs and benefits.

“It means less room to give a narrative and showcase sustainability stories,” said Müller.

To retain storytelling options, some companies are publishing multiple reports. Bayer, for example, included CSRD-compliant sustainability data in its 2025 annual report and published three other shorter reports that meet standards developed by the Sustainability Accounting Standards Board, Task Force on Climate-related Financial Disclosures and the Sustainable Finance Disclosure Regulation. It also created a standalone impact report that reads more like a traditional sustainability publication.

On the plus side, the focus on standardization makes peer comparisons easier. “In the past, most companies used their own company specific KPIs to track development, and now you have energy intensity of the operations measured in a relatively comparable way that really allows you to benchmark,” said Müller.

That benchmarking still involves a fair amount of manual work, however. The directive requires companies to publish reports, but not yet to make the data machine-readable. That requirement will follow when the European Commission finalizes the digital taxonomy that will support the process.

Companies are restating data

The move toward more standardized data and limited assurance prompted many companies to restate sustainability numbers, said Müller. That’s a reflection of better data and a “welcome quality improvement,” he added.

It’s worth nothing that it’s not just CSRD that’s driving this trend. Emissions accounting and target-setting standards are continuously evolving. Changes introduced by organizations such as the Greenhouse Gas Protocol, including the recent release of land-sector guidelines, can lead companies to restate data. The quality and availability of Scope 3 data is also slowly improving as companies prioritize primary data from suppliers ahead of industry averages.

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