Federal Supreme Court, 22.05.2026, 9C_178/2026
Facts
A taxpayer operating a sole proprietorship in real estate and holding shares in several companies was subject to various tax adjustments for the 2013 to 2016 periods by the Valais Cantonal Tax Administration. Following an initial unfavorable decision on an objection, the taxpayer appealed to the Valais Cantonal Court. The court partially upheld the appeal and referred certain points (child deduction, vehicle expenses, etc.) back to the tax authority for reassessment, but rejected the appeal for the remainder. This referral decision, classified as an interlocutory decision, was not subject to an admissible appeal before the Federal Supreme Court. (A, B)
Following a new decision on the objection by the tax administration, the taxpayer again appealed to the Cantonal Court, which rejected the appeal to the extent that it was admissible. The taxpayer then filed a public law appeal with the Federal Supreme Court, challenging both the final decision and the previous interlocutory decision. He requested the cancellation of several tax corrections, particularly concerning rental income, capital gains on the sale of works of art and vehicles, and the valuation of a claim against one of his companies. (B, C)
Law
The Federal Supreme Court reiterates the principles governing its scope of review. It applies federal law ex officio but only examines the grievances raised, except in cases of manifest legal errors. Violations of constitutional rights, such as the prohibition of arbitrariness (Art. 9 Cst.), must be the subject of qualified and detailed argumentation (Art. 106 para. 2 LTF). The review of the application of cantonal law is limited to a check for arbitrariness. The Federal Supreme Court bases its decision on the facts established by the previous instance, unless they are manifestly inaccurate or based on a violation of the law (Art. 105 para. 1 and 2 LTF). (c. 1, 2)
Regarding the merits, the judgment addresses the distinction between private wealth management, where capital gains are tax-exempt, and self-employed professional activity, where income is taxable. This classification depends on a set of indicators such as the systematic nature of the operations, the frequency of transactions, the short holding period, the use of significant borrowed capital, the link to the taxpayer's professional activity, and the intention to make a profit. (c. 4.3)
Concerning wealth tax, the entire net wealth is taxable at its market value (Art. 13 para. 1 and 14 para. 1 LHID). For claims, the market value generally corresponds to their nominal value, unless a proven risk of loss justifies a lower valuation. As the LHID does not impose a specific valuation method, the cantons have a certain margin of discretion, the exercise of which is reviewed by the Federal Supreme Court only from the perspective of arbitrariness. (c. 4.4.1)
Application to the specific case
The Federal Supreme Court declared several of the appellant's grievances inadmissible. Regarding vehicle insurance costs and a re-invoicing related to a contribution to the sole proprietorship, the Court noted that the appellant failed to sufficiently substantiate his appeal before the cantonal authority and did not demonstrate how the Cantonal Court's decision not to admit the case was erroneous. Consequently, the Federal Supreme Court could not examine these points. (c. 3.1, 3.2)
Regarding rental income of CHF 8,640 received in his private account, the Federal Supreme Court upheld the analysis of the lower court. The latter had classified this as income from self-employment based on several indicators: the appellant owns numerous vehicles, rents out parking spaces through his companies, and failed to prove a link between this income and rental costs he had personally incurred. The appellant merely presented his own version of the facts without demonstrating that the lower court's assessment of the evidence was arbitrary. (c. 4.1)
Regarding the gains realized from the sale of two paintings and two vehicles, the Federal Supreme Court upheld the classification as (ancillary) self-employment. The lower court correctly identified several indicators: the close link to the appellant's professional activity (as the sole shareholder of a company trading in art and luxury vehicles), the short holding period, the frequency of transactions, the systematic pursuit of profit, and his specialized knowledge. The appellant merely asserted that these were sales of private assets without validly challenging the indicators relied upon. (c. 4.3.1, 4.3.2)
Finally, regarding the valuation of his claim against his company G. SA for wealth tax purposes, the appellant had declared it at a value lower than its nominal value, citing a risk of non-repayment. The Federal Supreme Court ruled that the lower court's decision to use the nominal value, as recorded on the debtor company's balance sheet, was not arbitrary. The appellant failed to provide concrete evidence justifying a risk of loss that would warrant a discount. His general allegations were insufficient to demonstrate a violation of the law. (c. 4.4.2)
Outcome
The Federal Supreme Court dismissed the appeal to the extent that it was admissible. The court costs, amounting to CHF 4,000, were charged to the appellant. (c. 5, disp. 1, 2)
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