Actual emissions or default values

What a default value is

Paragraph 11(1) of Schedule 17 to the Finance Act 2026 lets the Treasury set by notice default values for determining the emissions embodied in CBAM goods, and paragraph 11(3) lets a value be set at a level that ensures there would be no advantage to any person in using it instead of determining the emissions under the regulations, including the advantage of not bearing the cost of measurement and verification. A default value is not designed to approximate the average mill; it is designed so that the importer who uses it pays at least as much as the importer who obtains real data. As at 13 September 2026 the notice had not been published in any form; the default values page tracks it.

The default route

Regulation 4 of SI 2026/995 provides that where a default value is used, the emissions are the weight of the good multiplied by the default value, with weight net of all packing at the time of import, in tonnes. The calculation is one line, and the return states the level of the default value used. No verification report is needed on this route.

The actual data route

Regulation 5 applies where no default value is used for the good, and it calculates the emissions in eight steps from verified emissions data for a monitoring period. It demands, under regulation 10, data about the installation's relevant emissions for a calendar year meeting the Commissioners' notice, with a verifier's opinion that the data are sufficiently accurate; under regulation 12, a verifier independent of the importer, the installation and every precursor installation, and accredited for the type of good; and under regulation 16, that the importer keeps the verification report for six years. The verification guide covers the verifier.

Mixing the two

Regulation 7 lets the routes mix within one good at the precursor step: where a precursor's installation has no verified data, the default value for the precursor multiplied by the weight of precursor used is added. A rolling mill with verified data for its own rolling that buys slab from a mill with none can use actual data for the rolling and the default for the slab. What an importer cannot do is use a default value for the good as a whole and then improve on it.

Why the choice is final

Paragraph 8(1) of Schedule 17 lets a return be amended only to correct an error, and paragraph 8(2) provides that no amendment may replace information determined using default values with information determined under the regulations. A return filed on default values is final as to their use: if the supplier's verified data arrives a month later and shows an intensity half the default, the importer cannot amend, cannot claim a repayment and cannot recover the difference. The prohibition runs one way only; an error in applying a default value, or in a return on actual data, can still be corrected.

What follows for the year

The decision is made for each good for each accounting period at the point of filing, with the data in hand. The filing deadline sets the deadline for the data: for the 2027 period the return is due before the end of 31 May 2028, and regulation 9(2) allows the monitoring period to be 2027, the preceding year with verified data, or the year of production. Data verified after May 2028 is too late for the first year. Once the notice is published, the cost of the default route can be estimated as expected tonnage multiplied by the default value and by an estimate of the sectoral domestic price, and that figure is the ceiling against which the cost of obtaining verified data is judged.

The figure the importer controls

Both routes rest on the weight. Regulation 4 of SI 2026/802 fixes it as the net weight without packing at the time of import, and regulation 12 lets an officer determine the weight, using estimates and comparisons, where the correct weight was not given or the record was not kept. An importer who declares net weight accurately and keeps the weighbridge tickets, packing lists and mill certificates behind it keeps the figure in its own hands.