The CBAM Compliance Calendar: Every Date That Binds You From Q4 2026 to 2028

Most CBAM planning documents we see have exactly one date on them: 30 September 2027. That date is real, and it matters. It is also the least useful date to organise around, because by the time it arrives every decision that determines your certificate bill has already been made.

The definitive regime turned CBAM from an annual reporting exercise into a rolling quarterly obligation. There is a price published every quarter in 2026 and every week from 2027. There is a holding test at the end of every quarter from 2027. There is a repurchase window that closes on 31 October and cancels anything left behind the following day. None of these appear on a compliance calendar built around a single filing deadline.

This is a CBAM deadline tracker, ordered by date, from the end of 2026 through to what is currently visible in 2028. For each entry: what happens, what you have to do, and who inside the business owns it.

First, the gate: does any of this apply to you?

Two conditions decide whether this carbon border adjustment timeline is yours to manage.

Authorised CBAM declarant status. Since 1 January 2026, only an authorised CBAM declarant may import CBAM goods into the EU. If your application is still pending with a national competent authority, that is the only deadline on your list that matters right now.

The 50-tonne de minimis exemption. The mass-based threshold introduced by the simplification package exempts importers below 50 tonnes of covered goods per calendar year. It is assessed annually and it is all-or-nothing: cross it and the full obligation attaches to everything you imported that year, not just the excess.

If you are an authorised declarant importing above the threshold, everything below applies.

Q4 2026: the quiet quarter that sets your 2027 bill

Nothing is due to be filed or paid in the last quarter of 2026. That is precisely why it gets wasted.

Early October 2026 - Q3 2026 certificate price published. The Commission sets one CBAM certificate price per calendar quarter during 2026, calculated in the first week following the end of that quarter as the weighted average of EU ETS auction clearing prices. The first of these, covering Q1 2026, was published in April 2026 at EUR 75.36 per tonne of CO2e. Each quarterly price is the figure that will be applied to the emissions embedded in goods you imported during that quarter, so your 2026 liability is being fixed quarter by quarter while you wait. The Commission maintains the published series on its CBAM certificate price page.

Owner: finance. Every published quarterly price should be entered into the accrual model the week it appears.

Through Q4 2026 - close out your actual emissions data for the year. Imports made in 2026 are declared in 2027. Whether you declare actual embedded emissions or fall back on default values is decided by whether you hold verified supplier data, and verifier capacity is the constraint, not your intention to use it.

Owner: procurement and trade compliance jointly.

Early January 2027 - Q4 2026 certificate price published. The final piece of the 2026 price series. At this point your 2026 liability is fully priced and can be calculated rather than estimated.

2027: the year the money moves

1 February 2027 - certificate sales open

This is the most under-noticed date in the entire regime. Certificate sales were postponed from 1 January 2026 to 1 February 2027, and they run through a centralised common platform operated on behalf of the Member States rather than through 27 national systems (International Carbon Action Partnership).

The practical consequence is a fourteen-month gap between incurring an obligation and being able to settle it. You accrued a liability across all of 2026 and could not buy a single certificate against it. On 1 February 2027 that accrued liability becomes purchasable, and the quarterly holding test starts running almost immediately afterwards.

Owner: treasury. Platform access, payment rails and internal purchase authority need to exist before this date, not after it.

From 2027 - weekly pricing replaces quarterly pricing

The quarterly price cadence was a transitional arrangement for 2026. From 2027 the certificate price is set weekly. That is a meaningful change in treasury terms: the price you pay depends on the week you buy, which turns certificate purchasing into a timing decision rather than an administrative one.

Owner: treasury, with a documented purchasing policy so that timing decisions are governed rather than improvised.

31 March, 30 June, 30 September, 31 December 2027 - the quarterly holding test

At the end of each quarter from 2027, an authorised declarant must hold CBAM certificates covering at least 50% of the embedded emissions in goods imported since the start of that calendar year. The threshold was reduced from an originally planned 80% during the simplification process, which lowered the working capital burden considerably but did not remove it (DEHSt, the German national competent authority).

Two things about these cbam quarterly surrender rules are routinely misread:

• The test is cumulative, not per quarter. At 31 December you need 50% coverage of the whole year to date, not 50% of Q4.
• It is a holding test, not a payment deadline. Failing it is a compliance breach in its own right, separate from any failure to surrender in September.

Owner: finance, with a quarterly control that reconciles imported tonnage to certificates held. This is the single control most worth building before February.

30 September 2027 - first declaration and first surrender

The first annual CBAM declaration covers calendar year 2026 and is filed through the CBAM Registry by 30 September 2027. The corresponding certificates are surrendered on the same date.

Note the date carefully. It is not 31 May, which is the deadline many teams carried over from earlier drafts and from the rhythm of other EU reporting regimes. It is 30 September, and the same date recurs annually thereafter.

Owner: trade compliance, with sign-off from whoever carries statutory responsibility for customs declarations.

31 October 2027 - repurchase requests close

After surrender, declarants may ask to sell unused certificates back. The rules are unforgiving in three specific ways:

1. The window closes on 31 October. Certificates that are neither surrendered nor covered by a repurchase request are cancelled without compensation on 1 November.
2. The cap is 50% of the year's total purchases, calculated across everything bought that year rather than per transaction. Buy 1,000 certificates in 2027 and you can sell back at most 500.
3. The buyback price is the price you paid, not the market price. Buy at EUR 75 and request repurchase in a week when the market sits at EUR 85 and you recover EUR 75.

Read together, these make over-buying a one-way loss. You cannot profit from holding surplus certificates, you can only recover half of your surplus at cost, and anything beyond that evaporates on 1 November. A purchasing policy that deliberately runs slightly under the holding threshold and tops up, rather than one that buys comfortably ahead, is the cheaper posture.

Owner: treasury and finance jointly.

2028 and beyond: visible but not yet fixed

Two developments will reshape this calendar, and both should be tracked rather than planned around, because neither is settled law.

Scope extension to downstream products. A Commission proposal would bring roughly 180 downstream steel- and aluminium-based products into scope from 2028, pulling in importers of machinery, fabrications, vehicle parts and appliances who are entirely outside the regime today (Linklaters). If your CN codes sit just outside current scope, this is the proposal to watch.

The ETS revision and the CBAM factor. The July 2026 ETS revision adjusts the free allocation phase-out and with it the CBAM factor trajectory, which is the multiplier that converts your embedded emissions into a certificate obligation. Changes here move every future year's bill without changing a single rule about how you file.

Article 9 third-country carbon price deductions. The methodology for deducting a carbon price already paid in the country of origin was published for consultation on 13 May 2026 and was still in draft through mid-2026. Any 2026 or 2027 budget that assumes a specific deduction from a Turkish, Indian or Chinese carbon price is working from unadopted rules. Model it as a range, not a line item.

The three dates people actually miss

If you take nothing else from this carbon border adjustment timeline, take these.

1 February 2027. Not because anything is due, but because nothing was possible before it and a great deal becomes possible after it. Treasury readiness on this date determines whether the first quarterly holding test is comfortable or frantic.

The quarterly 50% holding test. It is the only obligation in the regime that can be breached silently. There is no filing, no notification, nothing that prompts you. You simply either hold enough certificates at quarter end or you do not.

31 October. The repurchase window is short, capped and priced at historic cost. Teams that discover it in November discover it as a write-off.

What to do in the next 90 days

1. Confirm authorised declarant status is live, not pending, for every legal entity that will act as importer of record in 2027.
2. Run the 50-tonne test on actual 2026 volumes to date, per entity, and document the result. Assumed exemptions are the most expensive kind.
3. Build the quarter-end holding reconciliation now. Imported tonnage in, certificates held out, 50% coverage test, one owner. It has to work in March 2027, which means it has to be tested in 2026.
4. Get treasury onto the common central platform's access requirements before February. Payment authority and platform onboarding are not same-week activities.
5. Log every published quarterly price into the accrual model as it appears, so that the 2026 liability is a calculated number by January 2027 rather than an estimate carried into the declaration.
6. Put the Article 9 deduction in your model as a range with an explicit note that the methodology is unadopted, so that finance is not surprised when the adopted text narrows eligibility.

The declaration on 30 September 2027 is a reporting event. Everything that determines what it costs happens on the dates above.