Spark, in collaboration with Syntesia and Intellera Consulting, is proud to share the publication of a new Study on Taxpayer Identification Numbers (TINs) and possible verification instruments, conducted for DG TAXUD.
The study assesses the feasibility of introducing an EU TIN based on existing national identification numbers, as well as a dedicated tool to verify TINs, to support the automatic exchange of information under the Directive on Administrative Cooperation (DAC). Accurate taxpayer identification is essential for Member States to match the information they receive with national records and use it for tax compliance purposes.
The findings confirm that national TIN systems vary widely across the EU and that TIN inclusion in DAC exchanges remains uneven. Although an EU TIN would be legally and technically feasible, it would entail significant costs and operational complexity while offering limited added value. By contrast, a dedicated verification tool would address a concrete gap by making it possible to check whether a TIN exists and corresponds to the taxpayer concerned. The study therefore supports maintaining national TINs while developing a proportionate EU-level verification tool, potentially accessible to reporting entities on a voluntary basis.
Spark carried out the legal assessment, examining the coherence of both options with EU primary and secondary law, including the Treaties, the Charter of Fundamental Rights, the GDPR, the EUDPR, and the DAC. The analysis was complemented by national legal considerations which arose from the data collected at national level during the study. This national assessment drew on desk research and input from national legal experts in ten Member States, and its findings informed the refinement of the proposed options. The legal assessment confirmed that a verification tool would in principle be compatible with EU law, provided that a clear legal basis and the necessary safeguards are in place. While the DAC, as amended by DAC8, already required the Commission to develop such a tool and provided a legal basis for its use by tax authorities, the study found that extending access to reporting entities would have required targeted amendments to the Directive.
Building on these findings, the Commission’s proposal for a recast of the DAC, published on 24 June 2026, revises the provision introduced by DAC8, now Article 36 of the recast. The revised provision clarifies that the tool would verify the validity of a TIN and its correspondence to the taxpayer, and sets 31 December 2030 as the deadline for its development. In line with the study’s recommendations, the tool would be mandatory for tax authorities and voluntary for reporting entities, with those verifying a TIN through the tool able to report a reduced set of identification data. The proposal is now being considered by the European Parliament, which must be consulted, and by the Council, which must adopt it unanimously.
The final report is available here and the annexes are available here.