Cass. pen. Judgment no. 15448/2025: Foreign Tax Documents and Criminal Evidence

With decision no. 15448, filed on April 17, 2025, the Court of Cassation returns to the delicate issue of the admissibility, in criminal proceedings, of data transmitted by foreign tax authorities under the OECD Convention. The ruling, annulling without referral the judgment of the Court of Appeal of Milan, sets a firm precedent for lawyers, economic operators, and investigative authorities, who are interested in understanding when and how such documents can be admitted into Italian criminal proceedings.

The Procedural Case and the Principle Affirmed

In the specific case, the defendant M. C. was convicted for failure to declare following the acquisition by the Guardia di Finanza of tax reports received from the administration of another EU country. The defense invoked inadmissibility, arguing for the necessity of a rogatory letter under art. 729 of the Code of Criminal Procedure and the prohibition of "evidentiary forum shopping." The Cassation Court, referring to previous rulings (nos. 30068/2012, 6798/2016, 9083/2023), rejected the objection and affirmed that OECD administrative cooperation constitutes a sufficient autonomous channel to overcome these limitations.

In matters of international cooperation, information and documents acquired abroad and transmitted to Italian authorities under the OECD Convention on Mutual Administrative Assistance in Tax Matters, ratified by Law February 10, 2005, no. 19, as amended by the Protocol of May 27, 2010, ratified by Law October 27, 2011, no. 193, are admissible, in the absence of international rogatory letters, even without prior authorization from the party that provided them, provided that the general principles regarding the formation of evidence in adversarial proceedings are respected, and they can consequently be included in the case file for the trial pursuant to articles 234 and 234-bis of the Code of Criminal Procedure.

The Court emphasizes that documentary evidence, to be legitimately introduced, must still respect the adversarial principle enshrined in art. 111 of the Constitution and the examination in court under art. 431 of the Code of Criminal Procedure; it is therefore not an unlimited "passport."

The Relevant Regulatory Framework

The Supreme Court's reasoning is based on an interplay of national and international provisions:

• OECD Convention on Mutual Administrative Assistance in Tax Matters (Law 19/2005 and Law 193/2011);
• Articles 234 and 234-bis of the Code of Criminal Procedure: rules on documents and digital data admissible in trial;
• Article 191 of the Code of Criminal Procedure: inadmissibility of unlawfully acquired evidence;
• Article 729-bis of the Code of Criminal Procedure: cooperation with foreign tax authorities.

The Court interprets these provisions systematically: if the international agreement enables the exchange of information "for tax purposes," nothing prevents this information, once legitimately received by the Italian authority, from also being used in criminal proceedings, provided that the judge verifies its reliability and offers the parties the opportunity to contest it.

Implications for Taxpayers and Defense

The principle enunciated has significant operational implications:

• Defense Strategy: It can no longer be based solely on the lack of a rogatory letter; instead, it will be necessary to challenge the origin or authenticity of the document.
• Burden of Proof for the Prosecution: Although the evidence is "documentary," the Public Prosecutor must guarantee the judge access to information regarding the formation of the foreign document.
• Risks of Double Jeopardy: The same data can fuel both tax and criminal investigations, with possible repercussions on the European principle of ne bis in idem (ECtHR, Grande Stevens).

Conclusions

Judgment no. 15448/2025 consolidates the trend that recognizes full evidentiary value to documents transmitted through OECD administrative channels, provided their admission respects the guarantees of a fair trial. For professionals in tax criminal law, this means paying maximum attention in court, no longer to the form of international acquisition, but to the substance and verifiability of the data. From this perspective, tax cooperation is increasingly becoming a central tool in the fight against tax crimes, and the line between the administrative and criminal phases tends to blur, requiring an integrated and timely defense approach.