Federal Supreme Court, 05/19/2026, 9C_106/2025
Facts
As part of a special investigation into serious tax offenses, the Federal Tax Administration (FTA) seized assets belonging to a couple of taxpayers (A.A.________ and B.A.________) totaling CHF 4,337,222. Concurrently, the FTA requested that the Solothurn Cantonal Tax Office (the Tax Office) initiate proceedings for tax evasion. (A.a)
Based on an alleged request from the FTA, the Tax Office subsequently issued three tax attachment orders against the taxpayers for a total amount of CHF 1,387,688.65. These attachments were intended to secure the payment of tax arrears (back taxes) for the years 2012 to 2015, as well as potential fines for tax evasion and complicity in tax evasion. The Tax Office justified these measures by citing a risk to the collection of tax claims and referring to a future confiscation under Art. 70 of the Criminal Code. (A.b)
The taxpayers challenged these attachments before the Solothurn Cantonal Tax Court, which dismissed their appeal. They then appealed to the Federal Supreme Court, arguing that an additional tax attachment was disproportionate and arbitrary, given that their assets had already been fully seized by the FTA as part of the administrative criminal proceedings. (B, C)
Legal Analysis
The Federal Supreme Court reiterates that attachment orders are provisional measures. In this context, its power of review is limited to the violation of constitutional rights (Art. 98 LTF), which imposes a heightened duty of substantiation on the appellants. (consid. 1, 2)
The right to be heard (Art. 29 para. 2 Cst.), which includes the right to the administration of evidence, is not absolute. An authority may refuse to hear a witness through an anticipatory assessment of evidence if it determines, without arbitrariness, that such testimony would not provide any new decisive information to form its conviction. (consid. 4.1)
According toArt. 169 para. 1 LIFD, a tax attachment may be ordered if the payment of the tax due appears to be "at risk." This is a protective measure for which the mere plausibility of the risk is sufficient. Concurrently, as part of an investigation into serious tax offenses (Art. 190 LIFD), the FTA may order an administrative criminal seizure (Art. 46 para. 1 let. b DPA) on assets likely to be confiscated. (recital 5.1.1, 5.1.2)
The Federal Supreme Court clarifies the relationship between these two measures. An administrative criminal seizure ordered by the FTA already constitutes a provisional security measure that guarantees potential tax claims (tax arrears and fines). Consequently, when such a seizure is in place and sufficiently covers the tax claim, there is generally no room for an additional administrative tax sequestration. The risk of asset dissipation, which justifies sequestration, is already neutralized by the criminal seizure. Ordering a sequestration in addition to the seizure would be contrary to the principle of proportionality. (recital 5.2)
Application to the specific case
The Federal Supreme Court first examines the complaint regarding the violation of the right to be heard. It rules that the cantonal court did not act arbitrarily by deciding not to hear the FTA investigator. The relevant information, particularly regarding the amount of seized assets and the partial release of a portion of them, was already clearly evident from an email included in the file, and a hearing would likely not have provided any new elements. (recital 4.2)
On the merits, the Federal Supreme Court rules that the grounds invoked by the Tax Office to justify the sequestrations are manifestly insufficient and arbitrary. At the time the sequestrations were ordered, the FTA had already seized assets worth more than CHF 3 million (after a partial release), which amply covered the potential tax claim of approximately CHF 1.4 million. The assertion that payment was "threatened" is therefore contradicted by the facts. (recital 5.3)
Furthermore, the Tax Office falsely claimed to be acting at the "request of the FTA," which no element in the file confirms. Finally, the justification of a sequestration "in the sense of a confiscation according to Art. 70 SCC" reveals a legal confusion: sequestration is a provisional measure, whereas confiscation is a sanction pronounced at the end of the proceedings. This contradictory and erroneous reasoning constitutes arbitrariness and was not corrected by the previous instance. (recital 5.3)
This reasoning applies to both direct federal tax and cantonal and municipal taxes. Although Solothurn cantonal law regarding sequestration is not harmonized, its provision (§ 184 StG/SO) pursues the same goal as Art. 169 LIFD. The cumulative application of a criminal seizure and a tax sequestration for the same claims is therefore also arbitrary and disproportionate at the cantonal level. (recital 6)
Outcome
The Federal Supreme Court allows the appeal. It annuls the judgment of the Tax Court of the Canton of Solothurn and finds that the sequestration decisions issued by the Tax Office on May 23 and June 4, 2024, were issued in error. The costs of the federal proceedings are charged to the Tax Office, which must also pay legal fees to the appellants. The case is remanded to the cantonal instance for a new decision on the costs and fees of the cantonal proceedings. (recital 7, Operative part 1-4)
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