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The Annual CBAM Declaration: Content, the 30 September Deadline and How to Get There

The annual CBAM declaration is the point where everything else in the mechanism converges. For 2026 imports it is due by 30 September 2027 — a date moved back from 31 May by the Omnibus Regulation to allow more time for verification. Because each of its four elements is produced by a separate process with its own lead time, the declaration is best planned backwards from the deadline.

What the declaration contains

The annual CBAM declaration is submitted by the authorised CBAM declarant through the CBAM Registry and reports four things:

Quantity imported — by CN code, for the calendar year
Embedded emissions — total tonnes of CO₂ equivalent, derived from actual or default values
The verification report — where actual values are used, issued by an accredited verifier
Certificates surrendered — the number corresponding to the obligation

Only the first element comes from the declarant's own records. The second and third originate in the production installation, and the fourth is a consequence of the first three. This is why the declaration is, in practice, a supply chain deliverable rather than an administrative form.

Working backwards from 30 September

Each element has a lead time, and they run in sequence rather than in parallel.

When	What has to be true
Throughout 2026	Traceable emissions data is being recorded at the installation for the whole period
Late 2026	Verifier engaged, accreditation scope confirmed, site visit scheduled
Q1 2027	Verification performed; first verification reports expected from January 2027
From 1 February 2027	Certificates available for purchase
Q1-Q3 2027	Emissions data shared with the declarant; quarterly 50% holding maintained
By 30 September 2027	Declaration submitted and certificates surrendered

The constraint that governs the whole chain is that emissions data cannot be reconstructed retrospectively. A gap in 2026 records cannot be repaired in 2027; the only available response is to fall back to default values for that period, with the mark-up applied.

1The declaration for 2026 imports is due by 30 September 2027, moved back from 31 May by the Omnibus Regulation.
2It reports quantity imported, embedded emissions, the verification report and certificates surrendered.
3Certificate sales begin on 1 February 2027 and first verification reports are expected in January 2027.
4From 2027, at least 50% of the running obligation must be held in certificates at each quarter end.

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The quarterly holding rule

From 2027, a second obligation runs alongside the annual declaration. At the end of each quarter, declarants must hold at least 50% of the certificates corresponding to the embedded emissions of goods imported since the start of the year.

This changes the rhythm of the mechanism for suppliers as much as for importers. To calculate a quarterly position, the importer needs an emissions figure during the year, not only after verification. Data requests should therefore be expected periodically, and it matters that provisional figures are clearly labelled as such — an unlabelled estimate that later diverges from the verified number creates a commercial problem rather than a technical one.

There is no holding obligation for 2026, since certificate sales only begin in February 2027.

Where the reporting period is fixed

The reporting period is the year in which the goods were produced or imported into the EU, and it cannot precede 2026. Two consequences follow. Transitional-period data cannot be carried into a definitive-regime declaration. And a verified figure for one year cannot be reused for the next; each period requires its own calculation and its own verification.

What goes wrong most often

Verification timing. Verification of 2026 data concentrates in the first half of 2027 while accredited verifier capacity is still limited. Late engagement is the single most common cause of falling back to default values.
Precursor gaps. A producer's own data can be complete while a purchased precursor has none, which raises the declared figure through the default value and mark-up.
Inconsistent figures. The same installation and period reported differently to different customers. Sharing from a single source through the CBAM Registry removes this risk — see the CBAM Registry and O3CI portal.
Scope drift. A CN code added to the export mix mid-year that was never brought into the calculation.

Frequently asked questions

Who submits the declaration?

The authorised CBAM declarant established in the EU. Producers outside the EU have no declaration obligation.

Can a declaration be corrected after submission?

Corrections are provided for, but a shortfall in surrendered certificates attracts the €100 per tonne penalty, and paying it does not remove the surrender obligation. We cover this in CBAM penalties and enforcement.

Is a verification report always required?

Only where actual values are used. Default values are not subject to verification.

Does the September deadline apply every year?

Yes. The declaration for 2027 imports falls due by 30 September 2028, on the same pattern.

Sources

We work on preparing verified emissions data in time for the declaration and on coordinating with declarants, under our CBAM accounting and reporting service. You can contact us with your questions.