Divergence, Not Equivalence: Why Sustainability Reporting Still Runs on Two Rulebooks, and What That Means

For the past two years, a hopeful idea has floated over the sustainability reporting world: that the two big rulebooks, Europe's and the international one, would eventually converge into something close enough to a single exercise. Report once, the thinking went, and satisfy everyone.

A July 2026 analysis from Debevoise & Plimpton, published on the Harvard Law School Forum on Corporate Governance, is a useful reality check on that hope. Looking at the European Commission's recent review of its own standards, the authors conclude that the EU did not meaningfully move toward recognizing the international standards as equivalent, and did not restructure its rules to make life easier for companies caught by both. The two systems remain distinct, and may stay that way for a long time.

That sounds like an abstract problem for multinational legal departments. For mid-market manufacturers supplying the big consumer brands, it is closer to the ground than it looks.

Two rulebooks, and why worldwide groups end up under both

Since the EU's Corporate Sustainability Reporting Directive (CSRD) first applied to companies in 2024, two separate standard-setting projects have been running in parallel. On one side sit the EU's European Sustainability Reporting Standards (ESRS), with a related standard for groups headquartered outside the EU, the N-ESRS. On the other sits the International Sustainability Standards Board (ISSB), whose standards are published by the IFRS Foundation and which, as we wrote about earlier, has become the global baseline for sustainability disclosure.

The catch is that countries around the world are adopting the ISSB baseline in their own way, usually by publishing their own ISSB-derived national standards rather than the original text. So a company operating across many markets can find itself reporting under the ESRS in Europe and under several different ISSB-derived regimes elsewhere. That is what divergence means in practice: not one global standard, but a patchwork of related but non-identical ones, and a single group obliged to satisfy more than one at a time.

The big brands that ADB's clients supply, the L'Oréals, Unilevers, and Estée Lauders of the world, are exactly these worldwide groups. They are the ones assembling multiple disclosures under multiple frameworks, and they are the ones whose reporting burden determines how hard they push on their supply chains for data.

The two off-ramps that could have simplified all this

There were two mechanisms that could have collapsed some of this complexity, and it is worth understanding both because they solve different problems.

The first is equivalence. CSRD contains a procedure for the European Commission to decide that a non-EU country's reporting standards are good enough to stand in for the ESRS. If the Commission grants that recognition, a company caught by CSRD can discharge its European obligation using that third country's standards instead. This is the bridge across the EU-versus-international divide. Notably, the Commission has to make these determinations country by country, and it has neither issued an equivalence decision nor signaled that one is in progress.

The second is passporting, an ISSB initiative announced in October 2025. Because so many jurisdictions are adopting their own ISSB-derived variants, a global group can end up reporting under several flavors of what is nominally the same standard. Passporting would let a company report in a given jurisdiction using the original ISSB standards, with local conditions attached, rather than re-doing the work under each national variant. This is the bridge across the many ISSB-derived regimes. Whether it happens in any given country is entirely up to that country's authorities; the ISSB cannot compel anyone to accept it.

Either mechanism, taken far enough, would have eased the load at the top of the supply chain. Neither has yet delivered much relief.

Why the EU did not take the off-ramp

The sticking point is materiality, and it is the same distinction we have covered before.

The ESRS are built on double materiality: EU companies report both on how sustainability issues affect the business financially and on how the business affects people and the environment. The ISSB standards, by contrast, are built on financial materiality, asking what sustainability matters could affect a company's financial position, cash flows, or access to capital. The N-ESRS sits in a third position, focusing primarily on impact, a nuance we unpacked in our post on what the N-ESRS means for US companies.

That difference is precisely what blocks equivalence. Under CSRD, the Commission can only recognize a foreign standard as equivalent if that standard captures both sides of the materiality question, impact as well as financial. Because the ISSB baseline is anchored in financial materiality, it is unclear whether the EU will ever treat ISSB-derived standards as fully equivalent to the ESRS.

The Commission had a chance to soften this during its Omnibus review, when it published draft revised ESRS for consultation in May 2026. Various groups lobbied for closer alignment with the ISSB, including a proposal to let companies report financial and impact information in separate sections, so that a firm could publish an ISSB-compliant report and simply bolt on the extra impact material. The Commission declined. It was unwilling to create any hierarchy between financial and impact factors, which it viewed as undermining the double-materiality principle that defines European reporting. The revised standards got considerably leaner, but they did not bend toward the ISSB structure.

What did move: cross-referencing and interoperability

The picture is not one of two systems ignoring each other entirely. A few pragmatic bridges are in place.

The draft N-ESRS allow a reporting company that already prepares certain sustainability information under a local framework to cross-refer to that information in its N-ESRS report, provided it is presented in a neutral, balanced way. And EFRAG, the EU's technical adviser, has worked with the IFRS Foundation to publish interoperability guidance showing a high degree of alignment between the two systems' climate disclosures, and confirming that the ESRS notion of financial materiality lines up with the ISSB notion of materiality.

So the two frameworks talk to each other at the edges. What has not happened is the wholesale merger that would let a global group genuinely report once and be done. The overlap helps at the level of individual data points. It does not eliminate the second exercise.

Why this matters to you, even though none of it names you

Here is the part that reaches your business.

None of the mechanisms above, equivalence, passporting, cross-referencing, interoperability, changes who has to report. They change how much duplicated effort the reporting companies can avoid. When those simplifications stall, the reporting burden on the big brands stays high. And the burden on the big brands is what determines the volume and intensity of the data requests that arrive in your inbox.

If Europe had recognized the international standards as equivalent, a global brand might have been able to satisfy its European obligation with a single, largely financial-materiality report. Because it did not, that brand still has to produce a full double-materiality picture for Europe, including the impact side, alongside whatever ISSB-derived reporting it owes in other markets. The impact side is the demanding one for a supply chain, because impacts on people and the environment are exactly what cannot be answered from a company's own books. They have to be sourced from the value chain. From you.

This is the same pattern we keep coming back to. The regulation lands on a few hundred large companies. The information needed to satisfy it originates across thousands of suppliers who are never named in any of it. When the top of the chain cannot simplify, the requests do not slow down. They multiply, because your customer is now feeding the same underlying facts into more than one framework.

Where this leaves you

The strategic takeaway does not depend on how the equivalence and passporting debates eventually resolve, and that is the point. Whether the systems converge next year or never, every one of them ultimately runs on the same raw material: a defensible greenhouse gas inventory, credible product-level impact data, and metrics your customer can trust and reuse.

That is why the durable move for a mid-market supplier is to build the data foundation once and map it outward, rather than chasing each framework as it appears. A rigorous GHG inventory across Scopes 1, 2, and 3, product LCAs your customers can drop into their own numbers, and strong EcoVadis and CDP submissions are useful under the ESRS, under the ISSB, and under every derived standard in between. The politics at the top of the chain will keep shifting. The value of clean, verified, framework-agnostic data will not.

That groundwork is exactly the kind of work we do at ADB Sustainability. If your customers are already sending you questions shaped by more than one reporting framework, or you expect them to be soon, we would be glad to help you build a foundation that answers all of them at once.

ADB Sustainability helps mid-market manufacturers build the carbon accounting, LCA, EcoVadis, CDP, and ESG reporting infrastructure their customers and regulators increasingly expect. Get in touch.