Decisions of the Swiss Federal Supreme Court (CW 44–2026)

Overview of tax law decisions by the Swiss Federal Supreme Court published between October 26 and November 1, 2026:

Judgment of September 15, 2026 (9C_93/2026): Federal, cantonal, and municipal taxes for 2010–2013 (Geneva); the issue at hand is the taxation of divorced spouses. The 2010 tax period is barred by the statute of limitations due to the 15-year absolute limitation period for tax assessments. The absence of one spouse’s signature does not automatically render the joint tax return invalid; valid representation may also arise from other circumstances. Joint assessment and the individual allocation of the tax liability following divorce are conducted in separate proceedings. Furthermore, a tax burden exceeding 60% of taxable income is not, in and of itself, confiscatory. The taxpayers’ appeal is partially granted and otherwise dismissed.
Judgment of September 15, 2026 (9C_94/2026):Federal, cantonal, and municipal taxes for 2010–2013 (Geneva); At issue are the tax adjustments (reformatio in peius) made during the objection proceedings based on findings from a DAPE investigation (CHF 23.5 million in undeclared income for the years 2008–2015). The 2010 tax period is time-barred due to the absolute 15-year statute of limitations on tax assessments. Art. 6 of the ECHR does not apply to the present tax assessment proceedings despite the connection to criminal tax proceedings. Joint taxation during the marriage and the individual allocation of the tax liability following the divorce are handled in separate proceedings. Interest on arrears is not punitive in nature but serves to compensate for lost interest. A tax burden exceeding 60% of taxable income is not confiscatory per se, particularly when assets are growing steadily. The taxpayer’s appeal is partially granted and otherwise dismissed.
Judgment of September 10, 2026 (9C_659/2025) – scheduled for publication: Withholding Tax 2021–2022 (Ticino); Tax rate correction despite the expiration of the deadline under Art. 137(1) of the Federal Income Tax Act (DBG); The employer of an Italian cross-border commuter continued to apply tax rate U1 instead of tax rate S1 even after the taxpayer’s marriage in August 2021. The taxpayer did not file the request for a tax rate correction and refund until May 2024—after the deadline of March 31 of the following year had expired—which is why the cantonal authority declined to consider the request. The FTA argued before the Federal Supreme Court that, with the revision of withholding tax that took effect on January 1, 2021, this deadline was now mandatory for tax bracket corrections as well, rendering previous case law obsolete. The Federal Supreme Court held that the revision had merely clarified the relevant provisions without altering their substance, and that Parliament had specifically not adopted the Federal Council’s proposal to specify the employer’s certification obligations. The provisions on additional tax assessments and refunds (Art. 138, paras. 1 and 2, DBG) remained unchanged and continue to apply as lex specialis vis-à-vis Art. 137 DBG; therefore, a taxpayer who is not at fault for the employer’s tax rate error may still request a correction even after March 31. The FTA’s appeal was dismissed.
Judgment of September 28, 2026 (9C_625/2025): Real Estate Gains Tax 2021 (Schwyz); Discounting of an Interest-Free Deferred Portion of the Purchase Price; A corporation sold a piece of real estate for CHF 70 million. Of this amount, CHF 20 million was deferred interest-free and was due no later than a good five years later. The taxpayer requested a reduction in proceeds using a discount rate of 5%. The Federal Supreme Court noted that Art. 12 of the Federal Tax Act (StHG) does not prescribe a specific rate. Linking the rate to the advance payment interest rate for direct federal tax is appropriate and practicable; an individual risk premium is not required. The circumstances on the date of the transfer of ownership are decisive, which is why the rate of 0% in effect at that time applies, and subsequent interest rate increases are irrelevant. The taxpayer’s appeal is dismissed.
Judgment of September 30, 2026 (9C_552/2025): Import Duties 2017–2021; Agricultural Farming Operations; A farming couple from the Schaffhausen border region imported the produce from their German plots duty-free, even though sowing, plowing, fertilizing, and harvesting were largely carried out by contract contractors (see our article of September 14, 2025, regarding the lower court’s judgment A-3215/2023). The Federal Supreme Court held that the customs exemption requires that the domestic farmer actually cultivate the foreign land himself, whereby only the use of his own employees is permitted, but not extensive outsourcing to external contractors. The 1958 treaty with Germany does not lend itself to a dynamic interpretation that reflects today’s division of labor in agriculture. The couple’s appeal was dismissed to the extent that it was considered.

Non-occurrence / write-off: