Cohabitation in Switzerland: legal, tax and financial implications

Cohabitation in Switzerland: understanding the framework

If you live with your partner without being married or registered in a civil partnership, you are considered to be living in cohabitation.

Cohabitation is a de facto union based on a stable and ongoing common life. While it offers a high level of freedom, it does not provide the same legal protection as marriage or a registered partnership.

From a legal perspective, cohabiting partners are treated as two separate individuals, with no automatic rights or obligations towards one another.

What are the day-to-day implications of cohabitation? 

Unlike married couples:

• cohabiting partners have no legal duty to support one another financially,

• each partner retains ownership of their own assets,

• there is no automatic financial solidarity between partners.

In certain contexts, such as social assistance or debt enforcement proceedings, a partner’s financial situation may nevertheless be taken into account, depending on the circumstances.

Cohabitation and taxation in Switzerland 

For tax purposes, cohabiting partners are treated as entirely independent taxpayers:

• each partner files their own tax return,

• there is no joint taxation,

• no tax offset or income-splitting mechanism applies.

Depending on the distribution of income and assets within the couple, this individual taxation may be advantageous or disadvantageous.

What happens in the event of separation? 

In the event of separation, you are not entitled to a maintenance contribution for yourself, only for the joint children, even if you have reduced or given up your gainful activity. You will also not benefit from the AHV (Old Age and Survivors' Insurance) contributions paid by your former partner during your life together.

In the event of separation:

• no maintenance allowance is payable between partners,

• child support may be claimed for common children only,

• a partner who has reduced or given up their professional activity does not benefit from any automatic financial protection,

• AVS/OASI contributions paid by one partner do not generate any rights for the other partner.

Cohabitation and property ownership 

If your partner buys a house in their own name, you will have no rights to the property. If, on the other hand, you buy a property together, you will have to think about your inheritance.

Cohabitation has significant implications when it comes to real estate:

• if a property is purchased by one partner in their own name, the other partner has no legal entitlement to it,

• if a property is purchased jointly, ownership shares, financing and mortgage responsibilities must be clearly defined.

In all cases, purchasing property while cohabiting requires careful wealth and succession planning.

What about succession in the event of cohabitation? 

In Switzerland, a cohabiting partner is not a legal heir. In the absence of specific arrangements, the surviving partner does not automatically inherit, regardless of the length of the relationship.

Partners may designate one another as beneficiaries through a will or a succession agreement. Since the reform of Swiss inheritance law that entered into force in 2023, the compulsory share reserved for children has been reduced, offering greater freedom of disposition. However:

• statutory heirs retain protected rights (reserved portion),

• inheritance tax for cohabiting partners may be particularly high, as they are generally treated as unrelated third parties, depending on the canton.

Pension provision and cohabitation 

Cohabitation also involves specific rules in terms of pension provision.

At retirement, each partner receives 100% of their individual OASI pension, unlike married or registered couples, whose combined pensions are capped at 150% of the maximum OASI pension.

In the event of separation or death, cohabiting partners have no automatic entitlement to each other’s pension assets. In particular:

• OASI does not pay a survivor’s pension to cohabiting partners,

• benefits under the occupational pension scheme (second pillar) are paid only if the pension fund regulations allow it and the partner has been designated in advance,

• there is no automatic protection under private pension arrangements.

These specificities make voluntary and structured pension planning essential, especially where one partner is financially more vulnerable.

Cohabitation and children: rights and procedures 

When parents are not married, specific steps are required to secure the child’s legal status.

If the father is not married to the mother, paternity must be established through a formal recognition procedure. This process also allows both parents to apply jointly for parental authority.

Where parental authority is shared, parents may choose to give the father’s surname to their common children, in accordance with Swiss law.

With regard to a partner’s children, the adoption of a partner’s child is possible in Switzerland, subject to the applicable legal conditions. Such a decision has far‑reaching legal and inheritance consequences and should be carefully considered.

Entering into a cohabitation agreement 

If you choose not to marry or register a partnership but wish to formalise certain aspects of your relationship, you may enter into a written agreement, commonly referred to as a cohabitation agreement.

Partners are free to include the provisions they wish to clarify, such as:

• a list of each partner’s assets,

• the allocation of day-to-day expenses,

• financial responsibilities relating to children,

• the distribution of jointly acquired assets,

• maintenance arrangements in the event of separation,

• the establishment of a life insurance policy in favour of the partner.

This agreement has binding legal value and may be presented before a court if necessary. Properly drafted, it is an effective tool for preventing disputes and protecting both partners, particularly in the event of separation or death.