Commission Updates the CBAM Q&A: Verified Installation-Level Data Becomes the Benchmark

A new Q&A version for the definitive period

The European Commission's Directorate-General for Taxation and Customs Union (DG TAXUD) comprehensively revised its CBAM Q&A on 27 May 2026. This is the first major update since December 2024, and the first that is fully restructured around the definitive period. The revised version contains dozens of new questions covering accreditation and verification, the calculation methodology, sector-specific rules, and customs. Two priorities shift for importers. Verified installation-level emissions data move into focus as the expected standard, and legal responsibility for the CBAM declaration remains with the authorised declarant regardless of where the data comes from.

Default values come with a mark-up

From the Commission's perspective, verified installation-level data are the regular basis for the CBAM declaration. Default values remain available where verified data are missing. According to Carbon Herald, which summarised the revision on 28 May, they are no longer to be understood as a neutral fallback option, because they include conservative mark-ups that translate into higher certificate numbers per imported tonnage. Importers who rely on default values for their 2026 reporting will systematically pay for more CBAM certificates than would be necessary with cleanly verified data. Importers who have not yet established supplier data flows should now factor the mark-up into their internal cost calculations. That includes deciding in which sectors the investment in verified data pays off most.

Responsibility stays with the declarant

The Commission makes clear that legal responsibility for the accuracy of the CBAM declaration always rests with the authorised declarant. Errors in the verification report can also be enforced as penalties against the declarant; incorrect information from third parties may reduce liability at most. The new Q&A explicitly warns about third-party providers approaching importers with unsolicited paid verification services. Verified emissions data may only come from the producing installation operator, who provides the data via the CBAM Registry or through its own channels. Reliable data flows with these operators, supported by the verification rules of Implementing Regulation (EU) 2025/2546, become a compliance-critical task. Standard clauses on data quality, verification obligations, and liability now belong in every CBAM-relevant supply contract.

The calculation methodology leaves little room

Several new questions clarify the calculation methodology from the importer's perspective. The functional unit is by default the 8-digit CN code, with exceptions for fertilisers (defined via nitrogen content) and cement (via clinker content). Within an installation, the production process may not be artificially split, neither by the destination of the product nor by batch.

Companies running EU and third-country production in the same installation therefore cannot selectively report emissions. Precursors of EU origin enter the calculation with zero emissions but must still be reported by quantity. This noticeably relieves EU-internal value chains. Emission factors from LCA databases or life-cycle inventories are explicitly not accepted by the Commission. If the calculation results in a negative CBAM obligation, it is set to zero; offsetting against other imported goods is not possible. Companies that need to re-map an installation should work through the CN code logic and the treatment of precursors first.

The customs side becomes concrete

The customs side is structured comprehensively for the first time in the new Q&A. Importers without an EU establishment must mandatorily appoint an indirect representative, who then also acts as the authorised CBAM declarant.

A special rule applies for Northern Ireland. CBAM does not apply to imports into Northern Ireland itself. Goods of GB origin transferred via Northern Ireland into the EU, however, are subject to CBAM. Norway and Iceland are expected to incorporate the CBAM Regulation into the EEA Agreement as of 1 January 2027; from that date, the new TARIC code Y423 applies to goods previously released for free circulation in an EEA EFTA country. For threshold management, the Q&A clarifies that TARIC code Y128 must be used as soon as it is foreseeable that the 50-tonne threshold will be exceeded, while Y137 is only correct for importers who do not expect to exceed it.

Multinational groups may optionally consolidate the CBAM declaration via a single indirect customs representative across subsidiaries. Companies with scattered group imports should review their customs representation structure now.

What needs to be in place by 2027

The timeline is manageable but tight. According to the Commission, the first CBAM accreditations for verifiers will be issued by national accreditation bodies around September 2026. Accreditations are sector-specific; a verifier accredited for cement is not automatically qualified to verify aluminium installations.

From 1 February 2027, authorised CBAM declarants can purchase their first certificates, and the quarterly minimum holding requirement also applies from that same date. It must therefore be observed for the first time at the end of March for imports in 2027. The first annual CBAM declaration for imports in 2026 is due on 30 September 2027. Those who set up supplier data flows now, establish contacts with verification bodies, and build internal processes still have a time buffer. Those who only start in early 2027 will, in many sectors, have to fall back on default values and bear the associated surcharges.

Outlook

Alongside the Q&A update, the public consultation on the implementing act for the deduction of carbon prices paid in third countries runs until 10 June 2026 (see Issue 94). The new Q&A also signals that the Commission plans to publish country-specific default carbon prices that simplify the deduction without case-by-case proof. Companies importing in CBAM sectors should use the consultation deadline to submit their own or association-led responses.

Support

If you would like to understand how the updated CBAM Q&A concretely affects your data flows with third-country suppliers, your installation mapping by CN code, or your customs representation structure, please reach out to me at helge@kolum.earth.