CBAM: What the EU's Carbon Border Tax Now Means for Finance Teams

The EU's Carbon Border Adjustment Mechanism (CBAM) has moved from its transitional reporting phase into its definitive regime, and with that shift comes real financial exposure for the first time — not just paperwork. For finance teams at any company importing goods into the EU, and for the accountants advising them, CBAM has quietly become a genuine tax and compliance workstream rather than a sustainability side-project.

What CBAM actually does

CBAM puts a carbon price on imports of certain goods into the EU — initially covering carbon-intensive sectors including iron and steel, cement, fertilisers, aluminium, hydrogen and electricity. The idea is straightforward: EU producers already pay for their carbon emissions through the EU Emissions Trading System, so CBAM applies an equivalent charge to imported goods, preventing EU manufacturers from being undercut by producers in countries with weaker carbon pricing.

During the transitional period, importers only had to report the embedded emissions in their goods — no financial charge applied. The definitive regime changes that: importers now need to purchase CBAM certificates that correspond to the embedded emissions in the goods they bring into the EU, at a price linked to the EU carbon market.

Who needs to act

CBAM obligations fall on the importer of record — the entity declaring the goods to EU customs — not the overseas manufacturer. That means any business, including many outside the EU with EU subsidiaries or EU-facing supply chains, that imports in-scope goods needs to be registered and reporting. The scope has also been extending to cover more downstream products, so a "not in scope" assessment made during the transitional period is worth revisiting now rather than assumed to still hold.

What finance teams actually need to do

• Confirm current scope. Product coverage has expanded since the transitional phase — check current CN codes against your import book, not just the original 2023 list.
• Get embedded emissions data from suppliers. This is usually the hardest part in practice — many overseas suppliers are unfamiliar with CBAM's specific emissions reporting methodology, and getting auditable data from them takes lead time.
• Register as an authorised CBAM declarant where required, and build CBAM certificate purchasing into cash flow forecasting — this is now a real, variable cost line, not a compliance formality.
• Coordinate customs, procurement and finance. CBAM data typically starts in procurement and customs documentation but lands as a finance and reporting obligation — the handoff between teams is where gaps usually appear.

Where this overlaps with existing sustainability reporting

CBAM sits alongside, but is legally distinct from, reporting obligations like the Corporate Sustainability Reporting Directive (CSRD). A company can be in scope for CBAM without being in scope for CSRD, and vice versa — CBAM is triggered by importing specific physical goods, while CSRD is triggered by company size thresholds. Finance teams already building carbon accounting and emissions reporting capability for CSRD or voluntary disclosure purposes have a head start, since embedded-emissions calculation methodology draws on similar underlying data and expertise — but the two shouldn't be treated as the same compliance project.

Why this is a genuine content and advisory gap

CBAM is still relatively unfamiliar territory for many UK and Irish accountants, partly because it's an EU mechanism affecting non-EU businesses through their EU trade, which makes it easy to assume it's "someone else's regulation." For any client manufacturing or trading in the affected sectors with EU customers or EU-based operations, that assumption is now a real financial risk rather than a theoretical one — the definitive regime means unbudgeted certificate costs landing in accounts that haven't planned for them.

The practical takeaway

If you have clients importing steel, aluminium, cement, fertiliser or related goods into the EU — directly or via an EU entity — a CBAM scope review belongs on this quarter's checklist. The transitional, reporting-only phase gave everyone room to defer real engagement. The definitive regime doesn't.

Default values versus actual emissions data

Importers who cannot obtain verified emissions data from their suppliers can, in limited circumstances, use default values published by the European Commission instead of actual figures — but default values are set conservatively and are typically higher than a genuinely efficient producer's real emissions, meaning importers relying on defaults usually end up purchasing more CBAM certificates than they would with verified actual data. This creates a direct financial incentive to invest in getting real supplier data rather than falling back on defaults as a permanent solution, which is worth explaining plainly to clients who assume "we'll just use the default" is a costless shortcut.

Sector scope keeps expanding

The original CBAM sector list — iron and steel, cement, fertilisers, aluminium, hydrogen and electricity — was always understood to be a starting point rather than a fixed boundary, with downstream products and additional sectors added as the mechanism matures. A business that correctly assessed itself as "out of scope" based on the original product list needs to re-run that assessment periodically rather than treating the original scoping exercise as permanent, since a downstream product using an in-scope material as an input can itself be drawn into scope as coverage extends.

CBAM is part of a broader wave of mandatory climate-related disclosure — see our coverage of the global shift towards mandatory climate-related reporting for the wider regulatory picture finance teams are now navigating.