Art. 3 StHG: Tax liability based on personal connection
StHG Kommentar · 2026
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StHG Kommentar · 2026
Questa traduzione non è ancora disponibile. Versione disponibile visualizzata: English.
The Federal Act on Individual Taxation of 20 June 2025 replaces paras. 3 and 4 BBl 2025 2033:
The act enters into force on 1 January of the sixth year after its acceptance, unless the Federal Council sets an earlier date BBl 2025 2033. Voters accepted it on 8 March 2026, and entry into force is expected by 2032 at the latest AB 2026 S 439. The message describes the reform as making taxation independent of civil status BBl 2024 589. Until it takes effect, the joint-taxation regime discussed below governs.
Under settled case law, tax domicile lies where a person's centre of life interests is located. That place is determined by "der Gesamtheit der objektiven äusseren Umstände" (all objective external circumstances), and tax domicile is therefore "nicht frei wählbar" (not freely selectable) 9C_173/2024. A new domicile requires two elements:
A stay intended from the outset to be temporary can still found a domicile if it is planned for a certain duration and the centre of life actually moves there 2C_86/2021. The taxpayer need not sever every tie with the former place 9C_173/2024.
The tax concept follows the civil-law domicile of Art. 23 ZGB Art. 23 CC closely but is interpreted autonomously. The Federal Supreme Court notes that the tax provisions no longer refer to the ZGB, yet tax domicile is still modelled on the civil-law concept of domicile 2C_473/2018.
The main practical consequence concerns formal indicia. The place where papers are deposited or political rights exercised "spielt nicht eine entscheidende Rolle" (plays no decisive role). Such facts are only an indication if the rest of the person's conduct points the same way 9C_173/2024.
Two decisions show both directions:
The most recent decision, 9C_173/2024, sets the standard for relocations. The taxpayer cannot be required to prove the move "unumstösslich" (beyond any doubt). However, if no strengthening of ties to the new place compared with earlier years can be shown, the previous domicile is deemed to continue 9C_173/2024.
Whether the former domicile continues until a new one is acquired (the rule of Art. 24 para. 1 ZGB) depends on the context:
Between cantons, only the actual transfer of the centre of life decides.
A person has a single main tax domicile. Exceptionally, the case law accepts an alternating domicile where the ties to two places are of equal intensity. Tax sovereignty is then in principle divided, with the tax factors split in halves 2C_969/2010. For retired spouses living alternately in two places, the decisive criteria are mainly the length of the stays, the intensity of family and social contacts, and housing conditions 2C_969/2010. In 2C_969/2010, the court found on the decisive date of 31 December 2007 no stronger tie to either commune and divided the taxing right between Bern and Valais 2C_969/2010. The Ticino tax court treats this as a derogation from the principle of unity of domicile, reserved for ties of roughly equal intensity 80.2011.146.
The second alternative of Art. 3 para. 2 StHG, a special legal domicile assigned by federal law Art. 3 StHG, has little independent weight in practice. The case law discussed here points towards actual residence:
Both judgments predate the StHG. For persons under guardianship, the Vaud court held that "En droit fiscal, le domicile effectif l'emporte, abstraction faite de toute fiction" ("In tax law, the effective domicile prevails, disregarding any fiction"). Once a ward is placed definitively in an institution, the ward's tax domicile is at the institution's commune fi-1997-0032. The civil-law rule for minors (Art. 25 ZGB) Art. 25 CC therefore cannot simply be transposed.
For an unmarried employee, there is a natural presumption that the main tax domicile is at the weekday residence from which the person works 2C_397/2010. The presumption is rebutted if the person returns "regelmässig, mindestens ein Mal pro Woche" (regularly, at least once a week) to the family's place and maintains particularly close family and social ties there 2C_250/2013.
The procedural function of the presumption is decisive. It is "ein Element der Beweiswürdigung und nicht eine Beweislastregel" ("an element of the evaluation of evidence, not a rule on the burden of proof"). Once the taxpayer shows weighty and convincing indications for the weekend place, the presumption is rebutted. The canton of the work place must then prove weighty economic and possibly personal ties there 2C_397/2010.
The requirements tighten with age and length of stay:
A cohabiting partner at the work place usually tips the balance. Living with a partner in a 4.5-room flat there is normally sufficient for a work-place domicile, because such a relationship typically "sämtliche andern familiären und persönlichen Kontakte überstrahlt" (outshines all other family and personal contacts) 2C_250/2013. This is a strong pointer, not a conclusive one. In 2P.180/2003, a young taxpayer who had left the parental home for the first time kept her domicile in Valais despite cohabiting at the work place in Aargau. Both partners regularly spent their weekends and free time with their respective parents, so the ties to the parental family prevailed 2P.180/2003.
Cantonal courts apply the same framework. Vaud found the presumption rebutted for a teacher whose flat near the school served only practical needs, noting that a teacher keeps a certain distance from local residents who are also pupils' parents fi-2010-0032.
For married persons, contacts with the place where the family lives are in principle considered stronger than those with the work place. Married commuters and weekly commuters are therefore subject only to the taxing power of the family canton, provided two conditions are met 2C_403/2015:
Each condition marks a distinct exception:
Entry into a care home raises the question whether a new domicile is created. The Vaud tax court distinguishes by the character of the entry:
The decisions on this question are cantonal and should be read as applications of the general centre-of-life test.
Without a domicile, unlimited liability arises from a stay of at least 30 days with gainful activity, or 90 days without, "ungeachtet vorübergehender Unterbrechung" (notwithstanding temporary interruption) Art. 3 StHG. The French and Italian texts require a stay "sans interruption notable" or "senza interruzioni apprezzabili" Art. 3 StHG.
The Federal Supreme Court treats short interruptions as harmless while the connection persists. Once the threshold is reached, liability runs from the first day of the stay and ends on departure; a new stay must reach the threshold again 2C_186/2020.
Cantonal courts define "temporary" narrowly:
Students and patients. Art. 3 StHG contains no counterpart to the federal rule that a person domiciled abroad does not acquire a domicile or residence through a stay solely to attend an educational institution or to receive care in a medical institution Art. 3 DBG. The Federal Supreme Court nevertheless applied that rule analogously to Zurich cantonal taxes, while holding that ambulatory treatment is not such a special purpose 2C_186/2020. Vaud law contains an equivalent provision. The Vaud court describes it as a mere presumption, which the taxpayer can rebut by showing an intention to settle permanently at the place of study fi-2018-0265. In the reverse case of studies abroad, the same court held that the Swiss domicile continued while family ties in Switzerland predominated. It ended only once housing, work and personal ties had shifted abroad fi-2018-0265.
Tax domicile, as a fact establishing tax liability, "ist grundsätzlich von der Steuerbehörde nachzuweisen" (must in principle be proven by the tax authority) 2C_175/2008. The burden shifts where the previous domicile assumed by the authority appears very probable: the taxpayer must then prove the alleged move. This rule was developed for international cases and also applies between cantons 2C_175/2008. In 2C_175/2008, after about four unchallenged years in St. Gallen, the taxpayers had to prove a move to Thurgau by 31 December 2005, and failed 2C_175/2008.
The shift requires clear and precise indicia. The Federal Supreme Court formulates the rule in these terms under Art. 3 para. 2 StHG 2C_107/2013. The Ticino tax court shows its limit. Spouses had moved their civil domicile to Schwyz but kept a very large property in Ticino owned for decades. The statements of an employee, high staff and garden costs and electricity consumption did not suffice to establish unlimited liability in Ticino: the property's size could explain them, and earlier years showed similar figures. The court annulled the assessment and remanded for further investigation of medical, family and social ties and of the situation in the other cantons 80.2011.180. Weak indicia therefore do not shift the burden; the authority must first complete its own fact-finding.
9C_447/2024 confirms the allocation. The authority must prove the domicile even though the taxpayer has a duty to cooperate, and if clear indications make the authority's version very likely, the taxpayer must produce contrary evidence 9C_447/2024. The duty to cooperate under Art. 42 StHG covers the facts needed for that proof 2C_397/2010.
Under Art. 4b para. 1 StHG read with Art. 15 para. 1 StHG, the situation on the last day of the tax period decides 9C_447/2024. In 9C_447/2024, a move to Zug claimed for December 2020 was not established, so Ticino retained the taxing right for the whole year 9C_447/2024. The Ticino court below had held that an arrival notice in Zug on 16 December 2020 proved only the deposit of papers; the centre of vital interests had not yet moved by 31 December 80.2022.100. The Vaud court rejected the objection that taxing the whole period by reference to 31 December operates retroactively fi-2018-0163.
Before the Federal Supreme Court, a complaint under Art. 127 para. 3 BV may also challenge another canton's assessment for the same period, even if that assessment is already final (Art. 100 para. 5 BGG). The precondition is that the assessment can no longer be challenged by an ordinary remedy. In 9C_710/2022, the court abandoned its earlier practice under which the taxpayer's right of appeal could be forfeited 9C_710/2022. A subsidiary request against a canton is inadmissible if that canton has issued no final assessment for the period 2C_403/2015.
The earlier practice under the former OG allowed new facts before the Federal Supreme Court 2P.2/2003. Under the BGG, by contrast, the court is bound by the facts found by the lower instance. It reviews them only for arbitrariness 2C_994/2019, with a heightened duty to give reasons 9C_447/2024.
A canton forfeits its taxing right if, knowing or able to know the relevant facts, it waits unduly long, and another canton that has taxed in good faith would otherwise have to refund. For periodic taxes, forfeiture occurs at the end of year "n + 2" 2C_428/2020. In 2C_301/2017, Ticino's claim for 2011, asserted in February 2014, was time-barred, while its claims for 2012 and 2013 stood 2C_301/2017.
In supplementary-tax proceedings, the court requires even more promptness. Zurich forfeited its right by waiting almost four years after an anonymous but complete tip-off. Only the other canton, not the taxpayer, may raise forfeiture 2C_428/2020.
In international cases, domestic unlimited liability is examined first. Only if the other state also treats the person as resident does the treaty tie-breaker apply 2C_472/2010. In 2C_472/2010, the taxpayer remained domiciled in Aargau under Art. 3 DBG and StHG. Because Singapore also regarded him as resident, the closer personal and economic relations test of the treaty was then applied, again pointing to Switzerland 2C_472/2010. In 2C_473/2018, the treaty with South Africa likewise did not alter a Swiss centre of life 2C_473/2018.
The income and wealth of spouses living in a legally and factually undivided marriage are aggregated (Faktorenaddition) 2C_952/2020. The cantonal rule corresponds to Art. 9 para. 1 DBG 9C_249/2023.
The matrimonial property regime is irrelevant. The concept of an undivided marriage is interpreted autonomously for tax purposes, and a marriage contract choosing foreign law governs only the liquidation of matrimonial property, not marital rights and duties 9C_249/2023. BGE 122 I 139 put it categorically: "Das Steuerrecht berücksichtigt nicht, unter welchem Güterstand die Ehegatten leben, und ist dazu auch nicht verpflichtet" ("Tax law does not take into account the property regime under which the spouses live, and is not obliged to do so") BGE 122 I 139.
Joint taxation as such is constitutional. In BGE 110 Ia 7, however, the court held that progressive taxation requires the legislature to relieve married couples appropriately compared with single persons. Couples must not be taxed more heavily than economically equivalent cohabitants, although the Constitution leaves the method of relief open BGE 110 Ia 7. The more recent case law adds that joint taxation would have to be applied even if found unconstitutional, because of Art. 190 BV 9C_249/2023.
Separate taxation requires cumulatively 9C_249/2023:
Separate dwellings alone, as in a weekend marriage, do not suffice 9C_249/2023. A sporadic common life also keeps the marriage undivided 2C_502/2015. The Ticino tax court, citing Federal Supreme Court case law, adds two further cumulative criteria: the couple no longer appears united in public, and the separation is lasting (at least one year) or ends in divorce 80.2023.199.
The financial condition is applied realistically. In 2C_502/2015, keeping the former household account running for a limited time did not alter the overall picture of a marriage separated since the beginning of the year 2C_502/2015. The Zurich Administrative Court accepted separate taxation for 2017 although the husband moved out only on 1 December 2017 and the financial separation was completed only in October 2018. Later conduct sufficed to assume separate use of means retroactively for December 2017 ch-zh-administrative-court--sb-2022-00008.
Burden of proof. Under Federal Supreme Court case law, whoever relies on separate taxation must prove this exceptional situation, that is, a legally or factually separated marriage. Where the authority claims separate taxation against spouses seeking joint taxation, the burden lies with the authority 2C_952/2020. Geneva practice formulates the burden as resting on the spouses ATA/1191/2015. That formulation is consistent with the Federal Supreme Court's rule only where the taxpayers are the ones invoking separation.
Spouses may have separate main tax domiciles and still be jointly taxable. Separate main domiciles do not by themselves make them separate tax subjects: that requires, in addition, that support between them is limited to fixed monetary contributions 2C_952/2020. Otherwise, each spouse is taxed in their own canton of domicile, the factors of both are combined, and an allocation between the cantons is made 2C_952/2020. In 2C_952/2020, the tax authority bore the burden of proof and could not establish a factual separation, so joint taxation with allocation followed 2C_952/2020.
The Ticino tax court applied the same rule where the wife had moved to St. Gallen for health reasons while the husband stayed in Ticino and supported her financially. In the court's words, separate taxation of spouses does not come into consideration merely because they have two separate domiciles ("Una tassazione separata dei coniugi non entra in linea di conto unicamente per il fatto che questi hanno due domicili separati"). The marital community continued, so the factors were aggregated and split between the two cantons. As a consequence, the husband's payments to his wife were not deductible maintenance 80.2023.199.
Art. 18 StHG sets the following rules Art. 18 StHG:
The Federal Supreme Court's reasoning in 2C_502/2015 explains the principle: the personal situation on 31 December governs the whole period 2C_502/2015. The same judgment notes that the StHG version applicable in 2011 contained no rule on assessment upon marriage, divorce or separation, so the cantons were then free to legislate 2C_502/2015. Disputes about tax years for which that version applied may therefore turn on cantonal law.
Spouses in an undivided marriage exercise their procedural rights and duties jointly. They sign the return jointly, and a remedy is filed in time if one spouse acts within the deadline Art. 40 StHG.
The StHG, unlike Art. 13 DBG Art. 13 DBG, contains no rule on spouses' joint and several liability. It leaves the matter to the cantons BGE 122 I 139. The Vaud court links solidarity to para. 3: it flows from the principle that a married couple forms an economic unit. Yet the StHG contains no provision on solidarity between spouses ("La LHID ne contient pas de disposition relative à la solidarité entre époux"), so it does not decide whether solidarity exists or when it ends fi-2019-0097. Cantonal rules on spousal solidarity are therefore autonomous cantonal law, reviewed only for arbitrariness and constitutionality 2C_740/2020. The cantonal solutions differ markedly:
For the direct federal tax, the Federal Supreme Court sets a strict insolvency threshold: the spouse must have, at least in the medium term, no attachable income and no realisable assets. Insolvency must be proven, not merely made plausible, by the person seeking release. A 24 to 36 month repayment test is irrelevant 9C_233/2023. For cantonal taxes, the corresponding question arises under the cantonal solidarity rule.
The income and wealth of children under parental custody are attributed to the custody holder, with two exceptions: children's earned income and real-estate gains are taxed separately Art. 3 StHG. The line between attributed income and earned income is drawn by the nature of the payment:
For real-estate gains, the Federal Supreme Court notes that Art. 3 para. 3 StHG expressly provides for separate taxation. A canton therefore stays within the harmonisation framework when it taxes each spouse separately on their own gain 2C_704/2019.
Current law contains no specific attribution rule for children of unmarried parents under joint custody. The 2025 reform addresses this by splitting attribution in halves BBl 2025 2033.
Registered partners have the same position as spouses. This extends to maintenance during the partnership and to maintenance and property settlement on separation and dissolution Art. 3 StHG. The equivalence works in both directions:
The analogy does not extend further. In 9C_643/2023 (decided in November 2024), the Federal Supreme Court refused to treat a Canadian de facto union as equivalent to a Swiss registered partnership, because that regime concerns only same-sex persons. Maintenance paid to a former cohabitant was therefore not deductible. The court applied the same reasoning to cantonal taxes, because the cantonal provision has the same wording 9C_643/2023.
Cohabitants (concubinage) fall outside paras. 3 and 4 and are taxed individually. The Federal Supreme Court held that cohabitants are taxed separately like single persons and cannot be assessed as a unit, and that this separate treatment is not in itself contrary to equality. The same decision found, however, that wholly disregarding a cohabitant's maintenance burden for his children violated the ability-to-pay principle BGE 118 Ia 1. The Ticino tax court likewise excludes joint taxation of cohabiting couples 80.2016.306. The comparison with cohabitants remains the constitutional benchmark for married couples: tax laws that favour economically equivalent cohabiting couples over married couples are incompatible with equality before the law BGE 110 Ia 7.
Function, scope and relationship to the DBG
Art. 3 StHG binds the cantons to two connecting factors for unlimited tax liability of natural persons: tax domicile and qualified residence (paras. 1 and 2). It also fixes the unit of assessment for families: spouses' factors are aggregated, children's income and wealth are attributed to the holder of parental custody, and registered partners are treated like spouses (paras. 3 and 4) Art. 3 StHG.
The provision closely parallels Art. 3 DBG. The federal rule, however, contains two sentences without a counterpart in Art. 3 StHG Art. 3 DBG:
Privileges under the Host State Act remain reserved Art. 4a StHG.
The constitutional prohibition of intercantonal double taxation in Art. 127 para. 3 BV Art. 127 Cst. largely determines how "domicile" in Art. 3 para. 2 StHG is understood. Most leading decisions on the concept are double-taxation judgments, and the Federal Supreme Court applies the same criteria under Art. 3 StHG and Art. 3 DBG 2C_397/2010.
On a change of domicile within Switzerland, Art. 4b para. 1 StHG assigns liability for the whole tax period to the canton of domicile at the end of that period. Capital benefits are the exception: they are taxable in the canton of domicile when they fall due Art. 4b StHG. On the resulting importance of 31 December, see "The decisive date" below.
Versions and the adopted individual-taxation reform
Paras. 1 and 2 have remained unchanged since 1993. Para. 4 was inserted by the Partnership Act with effect from 1 January 2007 Art. 3 StHG. The message describes its aim as treating registered partners like spouses through a general reference rule . This includes maintenance after dissolution, which is deductible for the payer and taxable for the recipient . With effect from 1 January 2011, the German text of para. 3 replaced "elterliche Gewalt" with "elterliche Sorge". The change was terminological only .