In order no. 5971 of 17 March 2026, the Italian Supreme Court reaffirmed that bank investigations may also be extended to current accounts held in the names of a taxpayer’s family members, provided that the Tax Administration is able to demonstrate, on the basis of serious, precise and consistent evidence, that such accounts are in fact substantively attributable to the taxpayer under investigation. A mere family relationship is therefore insufficient: there must be a concrete body of indicia, such as the family member’s involvement in the taxpayer’s business or professional activity, or the inconsistency between the income declared by that family member and the transactions recorded on the account.

In the case at hand, the tax audit concerned a professional in respect of whom undeclared fees and suspicious bank transactions had emerged. The investigation had also been extended to accounts held in the name of her mother, who was considered to be operationally involved in the activities of the professional practice and to lack an income capacity consistent with the flows identified. The Supreme Court therefore held it lawful to attribute to the taxpayer also the sums passing through those accounts.

The decision also confirms the particularly far-reaching effect of Article 32 of Presidential Decree no. 600/1973: bank transactions give rise to a legal presumption of taxable income, and in order to rebut that presumption the taxpayer must provide specific and analytical counter-evidence in relation to each individual transaction. Generic objections or overall explanations are not sufficient.

From a privacy perspective, the order is particularly noteworthy because it indirectly addresses the balance between the Tax Authority’s investigative powers and the protection of private life. Extending audits to family members’ accounts inevitably involves personal data relating to third parties and therefore raises an issue of proportionality in relation to public interference with the private sphere. In this respect, the ruling appears to follow a clear line of reasoning: access to banking data may be regarded as justified only where it is not exploratory or indiscriminate in nature, but is instead linked to objective elements that have already emerged during the audit activity.

It is in this context that the reference to the most recent case law of the European Court of Human Rights on access to banking information must be understood. The Supreme Court, however, ruled out the automatic application of those principles in every tax dispute. On the one hand, any such complaint must be raised in due time before the courts of merits; on the other hand, a distinction must be drawn between arbitrary access and investigative activities forming part of an assessment already supported by specific indicia. In substance, the protection of privacy is not denied, but neither is it transformed into an absolute barrier to the exercise of tax assessment powers.

The ruling therefore confirms a strict approach: what matters is not so much the formal title to the bank account, but rather its actual substantive availability. At the same time, the issue of safeguards remains central, because the processing of banking data relating to persons other than the taxpayer must in any event remain grounded in the principles of necessity, proportionality and data minimisation.