CBAM Cost Uncertainty 2026: Errors in Published Values and the Verification Bottleneck

Why the cost calculation still doesn’t add up

CBAM has entered the definitive phase, yet many companies still find it difficult to calculate a reliable CBAM exposure for budgeting, pricing, and procurement decisions. Two factors are currently shaping the uncertainty. First, it concerns the data quality of published values that companies rely on when supplier-specific data is missing. Second, a growing verification bottleneck is emerging, which limits how quickly and whether companies can move from estimates to verified embedded emissions.

Published values are not yet stable enough for cost forecasting

Default values and benchmarks are important because they influence cost models when actual emissions data is not available or cannot be used at the necessary scale. In recent weeks, several industry discussions have pointed to rounding errors and broader data issues in published values released around the end of 2025. Reports describe inconsistencies that can change results depending on how values are rounded and applied to products and shipments. We also found around a thousand such errors in the file. Even if corrections are made later, companies face a practical problem today. If the reference values are not reliable, internal cost forecasts become fragile and procurement decisions can be distorted.

Verification capacity is becoming an operational bottleneck

From 2026, companies that want to avoid a cost disadvantage will increasingly need to use actual emissions data. This only works if those data can be verified in accordance with CBAM rules. The legal and procedural framework is being built. The Commission is consolidating legal acts and guidance, including relevant content on verification, in its CBAM documentation and guidance area. Market capacity, however, is a separate question. Accrediting verification bodies takes time, and the number of available verifiers will not immediately cover importers’ demand across the affected sectors in sufficient volume. While a more streamlined accreditation process can be expected for European verification firms, verifiers based in third countries will likely have to prepare for longer processes. It is also clear that European firms alone will not be able to cover demand. It is therefore advisable to get in touch with verification firms early and try to secure appointment slots.

What this means for importers and supply chains in 2026

The combination of unstable reference values and limited verification capacity results in three concrete risks. Financial planning becomes unreliable because CBAM costs can shift significantly with small changes in values, especially at high volumes. Commercial negotiations become more difficult because passing through prices, assigning data responsibilities, and agreeing contract clauses cannot be cleanly arranged if both sides do not trust the input values and the verification timeline. Compliance risk also increases, because a company may later face difficulties if it cannot justify why certain values were used, or if the expected verification is not possible in time and inspections as well as reporting obligations become more intensive.

Practical priorities for companies now

Companies should build cost models as ranges rather than point estimates, and conservative assumptions help if sensitivity to rounding and value changes is documented. A documented rule set for using published values reduces internal friction because it defines which source was used, which version date applies, and how rounding is handled consistently across shipments. Supplier outreach should be prioritized by exposure, with an initial focus on products and suppliers that account for the majority of embedded emissions and import value. Verification planning should start early so that companies can map their verification needs, identify potential verifiers, and synchronize internal timelines with realistic accreditation and capacity constraints. Robust evidence documentation should be established now, because records of data requests, supplier feedback, calculation logic, and internal controls help avoid confusion and rework if published values are corrected later.

Conclusion

CBAM cost uncertainty in 2026 is real. Rounding errors and data problems in published values weaken cost forecasting, and limited verification capacities slow the transition to verified actual emissions data. Companies that use 2026 as a year for governance and operationalization, with clean documentation and conservative modeling, will be best positioned for the next compliance steps.

Support

If you need support with CBAM cost modeling, a robust approach to applying published values, or support with verification for your supply chain, feel free to contact us directly at helge@kolum.earth.