How CBAM certificates work: key dates and limits
The Commission's factsheet on how CBAM certificates work (catalogue number KP-01-26-043-EN-N) is guidance, not law. It is still the first official overview of the whole certificate cycle in one short document. This article explains what the factsheet says, what the Regulation says underneath it, and which dates to enter in your calendar.
The cycle in one table
The certificate cycle runs on six kinds of date. Each one comes from a specific article of the Regulation or from the factsheet.
| When | What happens | Where it comes from |
|---|---|---|
| 2026 | No quarterly obligation. Nothing is bought or held during the year. | Factsheet; Art. 22(2) applies "from 2027" |
| 1 February 2027 | Certificates go on sale through the common central platformCommon Central PlatformCommission-managed platform through which Member States sell and repurchase certificates from 1 Feb 2027; reachable only by authorised declarants, only from the Registry; costs financed by declarant fees.. For 2026 imports, all required certificates are bought between 1 February and 30 September 2027. | Art. 20; factsheet |
| From 2027, end of each quarter | Your Registry account must hold certificates for at least 50% of the embedded emissionsEmbedded emissionsThe greenhouse-gas emissions released producing a good — direct emissions plus, where applicable, indirect (electricity) emissions — expressed per tonne of good; electricity uses kWh legally and may be converted to MWh operationally. This i of all goods imported since 1 January. | Art. 22(2) |
| 30 September, every year | Annual CBAM declarationAnnual CBAM declarationDeclaration filed via the CBAM Registry by 30 September of the year following import; carries embedded emissions, verification reports and certificate surrender. First: 30 Sep 2027 for 2026. and surrender of certificates for the previous year. The first time is 30 September 2027, for 2026. | Arts. 6 and 22(1) |
| 31 October | Last day to ask for surplus certificates to be bought back. | Art. 23(1) |
| 1 November | The Commission cancels certificates that are two years old and still on your account, without compensation. | Art. 24(1) |
What the 50% test is measured on
The 50% test uses a different base from your final bill. The factsheet says only "at least 50%". The Regulation is more specific, and the detail matters when you plan cash.
The Regulation allows one of two bases for the 50%. The first is the default values without the mark-up. The second is the number of certificates you surrendered for the previous year. You may use it if your customs declarations refer to the same goods by CN codeCN codeCombined Nomenclature 8-digit product classification; CBAM coverage defined per CN code in Reg. 956 Annex I; chapter-level entries (e.g. "72") cover all codes beneath. and country of origin. Either way, the adjustment for free allocation is taken into account (Art. 22(2)).
So the 50% is not half of what you will finally owe. If the Commission finds your account short, your national authority tells you. You then have one month to fix it (Art. 22(3)). A company that first crosses the 50-tonne threshold must meet the test by the end of the quarter after the one in which it crossed (Art. 22(2a)).
Buying back is limited
The buy-back in step 3 of the factsheet is narrower than "sell back what you did not need". These are the limits.
- You can ask for a buy-back only after you have surrendered, and only until 31 October of that year.
- The number is capped at the certificates you were obliged to buy under the quarterly test in the year you bought them (Art. 23(2)). You cannot sell back anything you bought beyond that obligation.
- You get back the price you paid, not the current price (Art. 23(3)).
- For 2026, you can sell back certificates bought in 2027 only in 2027 (Art. 23(2a)). On 1 November 2027 the Commission cancels all certificates bought for 2026 emissions (Art. 24(2)).
There is one relief. Suppose a declarant bought certificates because it expected to cross the 50-tonne threshold, and then it did not cross it. On request, all of those certificates are bought back (Art. 23(2)).
In practice, over-buying costs money. You pay for certificates that you hold but do not need until you surrender them. After two years the Commission cancels them with no compensation.
The quarter-end test and 31 October are separate dates
Two different events fall around the end of September and October. The quarter-end holding test happens on the last day of each quarter, so for the third quarter it is 30 September. The 31 October date is the deadline to request a buy-back. These are separate obligations.
The Commission's Q&A (question 3.1) gives 31 October for the third-quarter test. The Regulation says the end of each quarter, and the factsheet says the same. We follow the Regulation.
What the factsheet leaves out
- The price. The factsheet says the price is quarterly for 2026 and weekly from 2027, published on the Commission's certificate price page. For the third quarter of 2026, see our calculation. The Commission published the official figure, €82.32 per tonne of CO2e, on 5 October 2026.
- The final number. One certificate equals one tonne of CO2e. The number you buy is lower than your emissions, because the free-allocation adjustmentFree-allocation adjustmentReduction of certificates to surrender: FAA_g = SEFA_g,y × M_g; zero for electricity. Actuals → Column A path (Eq. 2–5, recursive for precursors); defaults → Column B path (Eq. 6). reduces it. Any carbon price paid in a third country also reduces it, where the evidence has been verified.
- If you are under 50 tonnes. None of this applies to you. You have no certificates to buy and no quarter-end test.
What it means for importers
Nothing is bought or held during 2026. From 2027, you need a quarterly figure, because your account is tested at every quarter-end. A company that can produce a number only once a year cannot pass a quarter-end test.
What to do
- Check whether you are, or will become, an authorised declarant. If so, enter 1 February 2027, each quarter-end, 30 September and 31 October in your calendar now. Treat them as four different kinds of date.
- Build a quarterly figure, not only an annual one.
- Decide how much to buy before you buy it. The buy-back window opens once a year, it is capped, and it returns the old price.
Stuck on this in your own import data? Write to us and we will look at it with you.
This article explains a Commission document and the rules behind it. It is not legal, tax or customs advice.
Informational only — not legal or tax advice. CBAM rules change; verify against the official source before acting.