Is Your Balance Sheet Ready for the UK Carbon Border Charge?

UK CFOs must map imports, register with HMRC and budget liability now: the UK Carbon Border Adjustment Mechanism (CBAM) starts on 1 January 2027.

CBAM is a tax on the greenhouse gas emissions embedded in specified imported goods. It is administered by HMRC, sits alongside the UK Emissions Trading Scheme, and lands on the importer of record rather than the overseas supplier. For finance leaders with steel, aluminium, cement, fertiliser or hydrogen in their supply chains, it is a new indirect-tax-style liability with a new data burden. It follows a year of similar compliance change: see our Autumn Budget scenario-planning checklist for the wider fiscal picture.

What does the UK CBAM actually charge, and on which goods?

The initial scope covers aluminium, cement, fertiliser, hydrogen, and iron and steel. Ceramics and glass are not in scope from 2027, and electricity is excluded. The liability is the CBAM rate for the relevant sector, set by HMRC each quarter, multiplied by the emissions embodied in the goods, less any qualifying carbon price already paid in the country of origin.

Importers can use verified actual emissions data from suppliers or government-set default values. Defaults are typically less favourable, so supplier data is a direct cost lever. Relief for overseas carbon prices, known as Carbon Price Relief, requires independent verification and a submission to HMRC.

Executive Action

• Ask procurement to list every imported product containing in-scope materials, by commodity code and supplier.
• Model liability under both default values and supplier-verified emissions to size the value of better data.
• Confirm which suppliers already pay a carbon price and can evidence it for relief.

Does your business cross the registration threshold?

Registration is required once the customs value of CBAM goods imported reaches £50,000 over the previous 12 months, or is expected to reach it within the next 30 days. According to A&O Shearman, the threshold was raised from the £10,000 originally proposed to reduce the administrative burden on smaller importers.

The trap is aggregation. The test applies to the whole legal entity, so a group importing small volumes through several divisions can cross the line without any single budget holder noticing. Registration is expected to open in late 2026, and reporting to date indicates that final penalty rules for registration failures had not been published by mid-2026, so treat the risk as uncapped until they are.

Executive Action

• Run 12 months of customs data by legal entity and compare it with the £50,000 threshold.
• Confirm whether your business, or a freight forwarder, is the importer of record on each declaration.
• Diarise HMRC’s registration window and name an owner for the application.

How should CFOs forecast and provision the liability?

Cash timing is unusually generous at first. According to KPMG UK, there will be a long first accounting period ending on 31 December 2027, with the return and payment due by 31 May 2028. From 2028, returns move to quarterly periods due on the last working day of the second month after each period ends.

That deferral is a cash-flow benefit, not an accounting one. The obligation arises as goods are imported from January 2027, so finance teams should agree with auditors how and when to recognise it under FRS 102 or UK-adopted IFRS, and reflect it in the 2027 budget, covenant headroom and pricing. Because the rate is reset quarterly, forecasts need a range rather than a point estimate. Businesses already reviewing working capital and refinancing exposure should add CBAM to the same model.

Executive Action

• Build a 2027 liability forecast with low, base and high emissions and rate scenarios.
• Agree the recognition approach with your auditor before the first quarter closes.
• Test covenant headroom and pricing decisions against the forecast range.

Which contracts and controls need to change before January?

Supplier contracts are the first gap. Most existing purchase agreements say nothing about emissions data, verification rights or who bears CBAM cost. Incoterms matter too: where the supplier acts as importer of record, liability and reporting may shift, and so may price. Internally, CBAM data spans procurement, customs, sustainability and tax, which is exactly where ownership tends to fall between functions.

Treat the return like a VAT filing: documented process, reconciled data, named preparer and reviewer. Penalties are expected to align with the VAT framework, so weak controls carry real cost. Our executive assessment tools and templates can help structure the review, and get in touch if you want a briefing tailored to your sector.

Executive Action

• Add emissions-data, audit-access and cost-allocation clauses to in-scope supplier contracts at renewal.
• Assign a single accountable owner and a documented return process, with tax, customs and sustainability inputs.
• Brief the Audit Committee on exposure, readiness and open regulatory unknowns.

Frequently asked questions

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