Italian Supreme Court rules bank data unusable without proper authorization in tax assessments

The Italian Court of Cassation, in ordinance No. 20694/2026 dated 18 June 2026, annulled a tax assessment on a property sale that had been based on bank‑account data obtained without a valid investigative authorization. The court held that such data are inadmissible when the authorization was lacking, did not contain a verifiable minimal content, or failed to define the scope and limits of the investigation. The ruling requires the exception to be raised in the initial tax appeal.

The case involved a professional who sold two property units at a declared price lower than the mortgage taken out by the buyer and lower than the OMI market values for the area. The tax authority used the discrepancy, along with unexplained bank withdrawals from the seller’s account, as evidence of unreported income. The Court of Cassation emphasized that, absent a proper authorisation – as required by articles 32‑1‑7 of DPR 600/1973 and 51‑2‑7 of DPR 633/1972 – the bank data cannot form part of the evidentiary framework, and the assessment must be re‑evaluated.