Verification and data quality
What “verified” means in the CBAM context
Verified emissions data is data that has been independently checked by an accredited third party. The verifier confirms that the emissions figures reported by a supplier accurately reflect the carbon intensity of their production process. Under HMRC's final CBAM framework, a return uses either independently verified actual emissions data (expressed as an emissions intensity per unit and verified to recognised standards) or HMRC's default values.
Self-declared vs third-party verified
Suppliers can provide emissions data in two ways. Self-declared data is calculated by the supplier themselves, without independent review. Third-party verified data has been audited by an accredited verifier. Only verified actual data can be used in a CBAM return. An unverified figure means the default value applies to that line. Self-declared data is still commercially useful: it shows where a supplier sits against the default value and which suppliers are worth taking through verification.
Why verified data saves money
When verified emissions data is not available, HMRC will apply default emissions values to your imports. These figures use default emission values. HMRC hasn't published UK values yet, so we use the European Commission's published defaults where they exist and sector averages otherwise. If your suppliers emit less than the default, you're overpaying, and verified supplier data is how you prove it.
How Oportax helps collect verified data
Oportax streamlines the data collection process so you can move from default factors to verified figures as quickly as possible:
- Sends structured data requests to suppliers in the format HMRC expects.
- Tracks which suppliers have responded and which need follow-up.
- Validates incoming data against expected ranges and flags anomalies.
- Stores all supplier responses with an audit trail for HMRC review.