Cohabitation is not a civil status and is not regulated under the Swiss Civil Code (ZGB). What that means for inheritance law, pension funds, taxes and children — and which gaps can be closed by agreement.
Around one fifth of all cohabiting couples in Switzerland are unmarried — among childless couples aged 25 to 64, the figure is around 44 per cent. Legally, these couples move in a space that the law has largely left empty: cohabitation is not a civil status, and the Swiss Civil Code (ZGB) contains no rules on it.
This creates an imbalance that most people notice only once it is too late. In terms of obligations, cohabitation is treated in many respects like marriage — in terms of rights, like a relationship that does not legally exist.
Key points at a glance
| Marriage | Cohabitation |
|---|
| Civil status | yes | no |
| Statutory regulation | ZGB Art. 90 et seq. | none |
| Mutual duty of maintenance | yes | no |
| Matrimonial property / equalisation of assets | yes | no |
| Statutory inheritance rights | yes | no |
| AHV survivor's pension | yes | no |
| Pension fund | entitlement | only if the regulations provide for it |
| Parental responsibility | automatically joint | declaration required |
| Taxes | joint assessment | separate |
| Inheritance tax | tax-free | varies significantly by canton |
| Taken into account in social assistance | yes | yes |
The last row is the core of the problem: it is the only one in which both columns agree — and it concerns an obligation, not a right.
Cohabitation is not a civil status
This is not a formality but the root of everything that follows. Art. 8 lit. d of the Civil Status Ordinance (ZStV) lists the civil statuses recorded in the civil register exhaustively: single, married, divorced, widowed, unmarried, and the variants of registered partnership. Cohabitation is not among them.
The ZGB contains no law on cohabitation. The effects of marriage — the duty of support and fidelity under Art. 159 ZGB, matrimonial property law, inheritance law, the power of representation — apply expressly only to spouses.
It follows for cohabiting couples that there is:
- no mutual duty of maintenance or support
- no matrimonial property law and therefore no equalisation of assets on separation
- no statutory inheritance rights
- no pension equalisation
- no power of representation in financial matters — the statutory right of representation under Art. 374 ZGB applies only to spouses and registered partners
There is, however, one exception, and it is often overlooked: in medical matters there is a statutory right of representation. Under Art. 378 para. 1 no. 4 ZGB, decisions on medical measures may be taken by whoever shares a household with the person lacking capacity and provides them with regular, personal support — ranking immediately after the spouse and ahead of children, parents and siblings.
"Qualified cohabitation" — and why the five years are a misunderstanding
Few terms are so often misrepresented. Guides regularly state that a cohabitation counts as "qualified" after five years. That is not accurate as stated.
What the Federal Supreme Court says
The authoritative formulation is found in BGE 118 II 235 and was confirmed in BGE 138 III 97: a qualified or consolidated cohabitation is a comprehensive life partnership intended to last for a longer period, if not permanently, with an essentially exclusive character, comprising a spiritual-emotional, a physical and an economic component — described in short as a community of housing, table and bed.
BGE 138 III 97 summarises the five-year rule as follows: for a cohabitation that had already lasted five years when proceedings began, a community of fate similar to marriage is to be assumed as a matter of factual presumption. BGE 114 II 295 holds that this reverses the burden of proof.
Two clarifications are decisive:
- This is a presumption with a reversed burden of proof, not a rigid deadline. Even a shorter cohabitation can be qualified — but then it must be proven.
- The rule originates from maintenance law, specifically from proceedings on the lapse of post-marital maintenance. The Federal Supreme Court also applies it in marital protection proceedings. It is not a general statutory definition.
Every area of law has its own threshold
| Area of law | Threshold | Basis |
|---|
| Post-marital maintenance | 5 years (presumption) | Federal Supreme Court case law |
| Social assistance | often 2 years or joint children | cantonal regulation, SKOS |
| Occupational pension provision | according to the regulations, often 5 years | Art. 20a BVG |
| Pillar 3a | 5 years of uninterrupted cohabitation | BVV3 |
| Inheritance tax | cantonal, 2 to 10 years | cantonal tax laws |
So anyone asking "from when do we count as cohabiting" gets a different answer depending on the context. For social assistance, the threshold may already be reached after two years, while the pension fund requires five.
Death: the biggest gap
This is where the absence of statutory regulation has the harshest effect. If a cohabiting partner dies without having made arrangements, the surviving partner is left empty-handed in three respects.
1. No statutory inheritance rights
The statutory order of succession recognises descendants, the parental and grandparental lines, and surviving spouses and registered partners. The cohabiting partner inherits nothing — not even after thirty years together.
Without a will, the estate passes to the deceased's relatives. In practice this regularly means: the flat that was shared but registered solely in the deceased's name passes to their siblings or parents.
The succession law reform of 1 January 2023 has, however, significantly widened the scope:
| Situation | freely disposable portion until 2022 | from 2023 |
|---|
| Testator with children | ¼ | ½ |
| Testator with parents only | ½ | everything |
| Without descendants, spouse or parents | everything | everything |
The compulsory portion of descendants fell from three quarters to half of the statutory entitlement, and the compulsory portion of parents was abolished entirely. For cohabiting couples with children, the freely disposable portion has thus doubled.
Two ways to arrange this:
- Will — holograph (entirely handwritten, dated, signed) or publicly notarised with the participation of two witnesses. Revocable unilaterally at any time.
- Contract of succession — in the form of a public testamentary disposition; both parties declare their intention simultaneously before the notary and two witnesses. Advantage: binding effect. Later, contradictory dispositions can be challenged.
For couples who want to secure each other, the contract of succession is usually the more robust solution — precisely because a will can be changed unilaterally by the survivor at any time.
2. No AHV survivor's pension
The AHVG links widows' and widowers' pensions exclusively to an existing or previous marriage. Cohabiting partners are not entitled, regardless of the duration of the relationship.
Not affected is the orphan's pension: it is due to joint children independently of civil status.
3. Pension fund: only if the regulations provide for it
Art. 20a para. 1 BVG is a discretionary provision. The pension fund may designate further persons as beneficiaries alongside those entitled by law — among others, the person who lived in an uninterrupted life partnership with the insured for the last five years before their death, or who must support their joint children.
But it is not obliged to. Where the regulations contain no provision for a life partner, there is no entitlement. The Federal Supreme Court confirmed in BGE 137 V 383 that pension funds may define the circle of beneficiaries more narrowly than the statute.
The provision applies both in the mandatory and in the extra-mandatory range.
### The most expensive mistake A will in the partner's favour does not create beneficiary status in occupational pension provision. The Federal Supreme Court held in BGE 142 V 233: a testamentary disposition appointing the life partner as heir does not permit the conclusion that a beneficiary designation under occupational pension law was intended — not even where she is appointed sole heir. An express reference to the relevant provisions of the fund's regulations, or at least to occupational pension provision, is required. Anyone who wants to protect their partner must submit the declaration of beneficiary the fund requires. Many regulations require this notification during the insured person's lifetime; the Federal Supreme Court leaves funds considerable latitude in how they structure it.
For pillar 3a the position is more favourable: the order of beneficiaries names the life partner — after five years of uninterrupted cohabitation or where they support joint children — in category 2, on an equal footing with the direct descendants. Here the entitlement applies by operation of law, without depending on any regulations.
Anyone who wants to control the split within this category can specify the entitlements more precisely. Without such a provision, descendants and the life partner share equally.
Taxes
Income and assets: separate
The aggregation of incomes applies only to spouses and registered partners. Cohabiting couples are each assessed individually at the rate for single persons.
Whether this is more favourable depends on the distribution of income. Where two incomes are roughly similar, separate assessment is usually advantageous because the effect of progression falls away. Where incomes are very unequal, by contrast, the married couples' rate is missing.
Inheritance tax: the biggest financial difference
Spouses are exempt from inheritance tax in practically all cantons. For cohabiting partners, everything depends on the canton of residence — and the range is enormous.
Broadly, three groups can be distinguished:
| Group | Effect | Examples |
|---|
| Fully exempt | no inheritance tax for life partners | Schwyz (no inheritance tax), Graubünden (Grisons), Zug |
| Exempt after a qualifying period | tax-free from a certain duration of shared household | Lucerne (Luzern; 2 years), Uri (5 years or joint minor children) |
| Preferential rate or allowance | reduced burden, but no exemption | Zurich (Zürich): allowance of Fr. 50'000 after 5 years in a shared household |
In a small number of cantons, by contrast, the full non-relative tariff applies — the highest that the respective law provides for. There, a substantial part of the estate can go to the tax authorities.
The qualifying periods also differ: they range from two, through five, to ten years. And even where an allowance applies, the non-relative tariff often applies to the amount exceeding it — in Zurich, for example, a multiple of the base rate.
Check the rules of your canton of residence specifically before setting up any succession planning. Cantonal tax laws are revised regularly; the conditions — duration, shared household, tax domicile — are formulated differently in detail.
Planning consequence: for larger estates, inheritance tax can considerably reduce the benefit of a testamentary designation. The tax burden therefore belongs before the inheritance planning, not after it. Anyone free to choose their place of residence should factor the canton into their considerations.
Children in cohabitation
Parental responsibility does not arise automatically
This surprises many parents. Art. 298a ZGB: where the parents are not married to each other, joint parental responsibility only arises through a joint declaration.
Until the declaration is made, parental responsibility rests with the mother alone (Art. 298a para. 5 ZGB).
In the declaration, the parents confirm that they are willing to take joint responsibility, and that they have reached agreement on custody, personal contact or care shares, and on the maintenance contribution.
| Point in time | Competent authority |
|---|
| together with the acknowledgement of paternity | civil registry office |
| later | child protection authority (KESB) at the child's place of residence |
If one parent refuses, the other may apply to the child protection authority (Art. 298b ZGB).
Child maintenance: identical to that of married parents
The child's maintenance claim is independent of civil status. Maintenance agreements only become binding on the child once approved by the child protection authority, and the law prescribes a minimum content.
A waiver of child maintenance is not possible — the claim belongs to the child, not to the parents.
Social assistance: the obligation without the right
This is where the asymmetry mentioned at the outset shows most clearly.
Although cohabiting partners have no statutory duty of maintenance towards each other, the income of the non-supported partner is taken into account in social assistance. In the Canton of Zurich, a cohabitation counts as stable where the life partnership has lasted more than two years, or the couple runs a household with joint children. Those affected can rebut this presumption.
Where a stable cohabitation exists, need is calculated as for a married couple, and the economically independent partner is required to pay a cohabitation contribution. Their assets are also taken into account.
The Federal Supreme Court upheld this practice in BGE 141 I 153: taking a cohabitation contribution into account is neither arbitrary nor unequal treatment where the cohabitation is stable. It is expressly irrelevant whether the financially capable partner declares a willingness to actually pay the contribution.
The asymmetry in one sentence: in cohabitation, the state accesses the partner's income as if a duty of maintenance existed — on death, it treats the same relationship as if it had never existed.
The cohabitation agreement
No particular form required — but sensible in writing
Contracts require a particular form only where the law prescribes one. For the cohabitation agreement it does not. It is valid without any particular form.
Written form is nonetheless strongly advisable: without a written basis, it is hard to prove on separation who contributed what and who made which payments.
Certain content nonetheless requires a form:
| Content | Form required |
|---|
| Disposition under inheritance law | will or contract of succession |
| Transfer of real property | public notarisation |
| Pension fund beneficiary designation | notification to the fund in accordance with its regulations |
The trap: the simple partnership
Where there is no agreement, the Federal Supreme Court fills the gap — and not with matrimonial property law. In BGE 108 II 204 it expressly rejected an analogous application of matrimonial property principles and instead held that the applicability of the rules on the simple partnership must be assessed according to the specific circumstances. BGE 109 II 228 applies the liquidation provisions where both partners worked together towards an economic result.
This leads to results that surprise many:
- Equal shares regardless of contributions. In the absence of any other agreement, each partner has an equal share in profit and loss, irrespective of the nature and size of their contribution. Someone who financed 80 per cent may end up at 50 per cent.
- Joint and several liability towards third parties, where the couple acts jointly.
- No return of assets contributed. In liquidation, there is only a claim to the value, not to the return of the contributed item itself.
- Dissolution on the death of a partner.
What the agreement should cover
- Inventory — who contributed what, who owns which purchase
- Cost sharing for housing and household
- Co-ownership shares in real property and the treatment of unequal financing contributions
- Loans between the partners and their repayment
- Compensation for reduced employment due to childcare — the most important point for the caring partner, since there is no statutory equalisation
- Powers of attorney for illness and incapacity
- Procedure on separation — housing, joint purchases, deadlines
Cannot be regulated in the cohabitation agreement: statutory inheritance rights (only via a will or a contract of succession), child maintenance to the child's detriment, the effects of civil status, and AHV and pension fund entitlements.
Checklist: the four documents
A cohabitation agreement alone is not enough. Full protection usually requires four building blocks:
| # | Document | Covers | Form |
|---|
| 1 | Cohabitation agreement | assets, costs, separation | no particular form required, written form recommended |
| 2 | Will or contract of succession | estate | holograph or publicly notarised |
| 3 | Declaration of beneficiary to the pension fund | occupational pension provision | according to the regulations |
| 4 | Advance care directive | representation in case of incapacity | holograph or publicly notarised |
The fourth point is the one most often forgotten. Without an advance care directive, the cohabiting partner has no power of representation in asset and administrative matters — neither towards banks nor towards authorities, because Art. 374 ZGB applies only to spouses and registered partners. The child and adult protection authority (KESB) then becomes responsible.
In medical matters the position is better: there, under Art. 378 para. 1 no. 4 ZGB, a statutory right of representation exists for persons in the shared household who provide regular, personal support. An advance care directive, however, gives the partner first rank and additionally covers asset management.
When legal advice is worthwhile
- A shared property with unequal financing contributions — the most common point of dispute on separation
- One partner reduces their employment for childcare
- Larger assets — the interplay of inheritance law and inheritance tax
- International couples — different nationalities, assets abroad, recognition of foreign dispositions
- Immigration law questions — family reunification generally presupposes marriage; for cohabiting couples with third-country nationality, the position is considerably narrower
- Self-employment or a business interest held by one partner
- An existing will from before 2023 — the new compulsory portions open up more scope
Sobiera Legal Consulting advises on cohabitation agreements and on securing the position of unmarried couples, including in international constellations, in German, English, French, Ukrainian and Russian. The initial consultation is billed on a time-spent basis; further work depends on the scope of the mandate.
Related topics
Sources
- Civil Code ZGB (SR 210), Art. 159, 276, 287, 289, 298a, 298b, 374, 378, 457 et seq., 462, 470–473, 495, 498, 505, 512, 522, 657 — fedlex.admin.ch
- Code of Obligations OR (SR 220), Art. 11, 530 et seq., 533, 544, 545, 548–550
- Civil Status Ordinance ZStV (SR 211.112.2), Art. 8 lit. d
- Federal Act on Occupational Pension Provision BVG (SR 831.40), Art. 20a, 49 para. 2
- Ordinance on the Tax Deductibility of Contributions to Recognised Pension Schemes BVV3 (SR 831.461.3), Art. 2
- Federal Act on Old-Age and Survivors' Insurance AHVG (SR 831.10), Art. 23, 24, 24a
- Federal Act on Direct Federal Taxation DBG (SR 642.11), Art. 9
- Federal Act of 18 December 2020 amending the ZGB (succession law), AS 2021 312, in force since 1 January 2023
- BGE 108 II 204 · BGE 109 II 228 · BGE 114 II 295 · BGE 118 II 235 · BGE 137 V 383 · BGE 138 III 97 · BGE 141 I 153 · BGE 142 V 233
- Federal Tax Administration, tax information dossier — inheritance and gift taxes; cantonal tax laws, including § 175 StG ZG, Art. 107b StG GR, Art. 158 StG UR, § 11 EStG LU, § 21 ESchG ZH
- Social Assistance Manual of the Canton of Zurich, ch. 6.2.03 and 17.5.01; SKOS guidelines
- Federal Statistical Office, Family and Generations Survey; Structural Survey 2022–2024
Status: August 2026. This article provides an overview and does not replace legal advice in an individual case. Cantonal rules on taxation and social assistance differ; the law at the place of residence governs.
Frequently asked questions
What is cohabitation?
The shared life of a couple without marriage and without a registered partnership. Cohabitation is not a civil status — Art. 8 lit. d of the Civil Status Ordinance (ZStV) lists the civil statuses exhaustively, and cohabitation is not among them. The Swiss Civil Code (ZGB) contains no rules on it.
From when does a couple count as cohabiting?
There is no uniform threshold. The commonly cited five years come from maintenance law: under the case law of the Federal Supreme Court, a cohabitation that has already lasted five years when proceedings begin gives rise to a factual presumption of a marriage-like community of fate. In social assistance, two years often applies depending on the canton; in occupational pension provision, the fund's own regulations apply; in tax law, cantonal rules apply. The threshold therefore depends on the area of law.
Does my cohabiting partner inherit automatically?
No, nothing at all. Statutory inheritance law recognises only descendants, the parental and grandparental lines, and surviving spouses and registered partners. Cohabiting partners have no statutory right to inherit. Anyone who wants to benefit their partner needs a will or a contract of succession.
How much can I leave my partner?
Considerably more than before, since the succession law reform of 2023. Anyone with children can freely dispose of half the estate — until 2022 it was a quarter. Anyone leaving only parents can now dispose of everything, since the parents' compulsory portion has been abolished entirely. Anyone leaving neither descendants, a spouse nor parents could always dispose freely.
Will my partner receive my pension fund benefits?
Only if the pension fund's regulations provide for it. Art. 20a BVG is a discretionary provision: the fund may designate a life partner as beneficiary, but is not obliged to. Where the regulations contain no such provision, there is no entitlement. Check with your fund and, if applicable, submit the required declaration of beneficiary.
Is a will enough to name my partner as a pension fund beneficiary?
No. The Federal Supreme Court has held that appointing an heir by will does not show an intention to designate a beneficiary under occupational pension law — not even where the partner is appointed sole heir. An express, regulation-compliant notification to the pension fund is required.
Is my partner entitled to an AHV widow's or widower's pension?
No. The AHVG links widows' and widowers' pensions exclusively to an existing or previous marriage. Cohabiting partners have no entitlement, regardless of how long the relationship has lasted. The orphan's pension for joint children is not affected: it is independent of civil status.
How are cohabiting couples taxed?
Separately. The aggregation of income under Art. 9 DBG applies only to spouses and registered partners. Each partner is assessed individually at the rate for single persons. Depending on how income is distributed, this can be more or less favourable than a joint assessment.
How high is inheritance tax for cohabiting partners?
This is governed cantonally and is the biggest financial difference from marriage for cohabiting couples. The range runs from full exemption, through exemption after a qualifying period, to the full non-relative tariff. Life partners are fully exempt in, for example, Schwyz, Graubünden (Grisons) and Zug; Lucerne (Luzern) exempts them after two years, Uri after five years of a shared household. Zurich (Zürich) grants no exemption, but an allowance of Fr. 50'000 after five years — the non-relative tariff applies to the amount exceeding it. Check the rules of your canton of residence specifically.
Do unmarried parents automatically have joint parental responsibility?
No. Under Art. 298a ZGB, joint parental responsibility only arises through a joint declaration by the parents — at the civil registry office if made together with the acknowledgement of paternity, otherwise at the child protection authority. Until the declaration is made, parental responsibility rests with the mother alone.
Does a cohabitation agreement need to be notarised?
No. Under Art. 11 OR, contracts require a particular form only where the law prescribes one — and it does not for the cohabitation agreement. Written form is strongly advisable for evidentiary reasons, but is not a condition of validity. Certain content nonetheless requires a form: dispositions under inheritance law require a will or a contract of succession, and the transfer of real property requires public notarisation.
What happens to shared assets on separation?
There is no matrimonial property law to govern the settlement. The Federal Supreme Court applies the rules on the simple partnership depending on the specific circumstances. The result can be surprising: under Art. 533 para. 1 OR, in the absence of any other agreement, the partners have equal shares in profit and loss, irrespective of the nature and size of their contributions. Anyone who has contributed more should record this contractually.