5.The annual cycle in the definitive period

1. Declare. By 30 September each year the declarant submits a CBAM declaration for the previous year: quantities, embedded emissions, certificates owed and verification reports. The first one is due 30 September 2027, for 2026.
2. Buy. One certificate = one tonne of CO2e. Sales start 1 February 2027 on a central platform. Certificates cannot be transferred, even within a group.
3. Price. From 2027: the weekly average EU ETS auction price. For 2026 emissions: the average for the quarter in which the goods were imported.
4. Hold (from 2027). At each quarter end, hold certificates for at least 50 % of emissions imported so far that year. There is no quarterly rule for 2026 imports; those certificates are bought between 1 February and 30 September 2027.
5. Surrender certificates for the previous year by 30 September.
6. Repurchase and cancel. Excess certificates can be sold back by 31 October; unused older ones are cancelled on 1 November.

Date	What happens
1 Jan 2026	Definitive period starts
31 Mar 2026	Last date to apply for authorisation and keep importing meanwhile
1 Feb 2027	Certificate sales start
31 Mar 2027 (and each quarter end)	50 % holding check for 2027 imports
30 Sep 2027	First declaration and surrender, for 2026
31 Oct 2027	Last date for repurchase request
1 Nov 2027	Remaining 2026 certificates cancelled

WATCH OUT The Commission Q&A lists "31 October" as a quarterly check date. The law says "end of each quarter", which is 30 September. Follow the law.

KEY Your real deadline is earlier: your customer needs verified data before 30 September. Plan to finish verification of 2026 data in the first half of 2027.

Sources: REG Art 3(24), 6(1)-(2), 17(7a), 20(1), 21(1)-(2), 22(1)-(2), 23, 24, 36(2); FS-CERT; QA §3.1-3.5 p.21-23, §5.11 p.44.