Living together without marrying: what Swiss law does not give you

Switzerland has a detailed rulebook for married couples. Property, pensions, inheritance, tax, divorce, all of it written down and applied automatically whether the couple ever thinks about it or not.

For unmarried couples living together, that rulebook is mostly blank. Not hostile, just absent. And absent is the part that catches people, because nothing announces itself. You find out what was missing at the worst possible moment.

There is no such thing as a cohabitation property regime

Swiss matrimonial property law has three regimes, and one of them applies to every married couple automatically. Unmarried couples get none of them.

So when you buy something together, own something together, or one of you funds something the other's name is on, ordinary civil law applies and nothing is presumed in your favour. There is no pot of shared gains to divide, and no rule that says what you built together belongs to you both.

This is the root of everything below. Most of what married couples get for free, you have to create on paper.

Your partner does not inherit. At all.

This is the one worth knowing tonight.

A cohabiting partner is not an heir under Swiss law. Without a will, they inherit nothing. Not the flat you shared, not a share of the savings, nothing. The estate goes to your relatives in the order the law sets out, and your partner of twenty years is a stranger to that order.

People assume time together counts for something. It does not.

The good news is that the fix is genuinely straightforward, and it got easier recently. Since 1 January 2023 the compulsory share reserved for parents was abolished. So if you have no children, you may now leave your entire estate to your partner. If you do have children, roughly half remains yours to give freely.

A will, or a notarised inheritance contract if you want it harder to change, is the entire solution. It is an afternoon of admin against a consequence that is otherwise absolute.

Inheritance tax is a separate matter and it is cantonal. Several cantons tax an unmarried partner at the highest rate applied to unrelated persons, which can be substantial. That is worth asking about locally before you assume a will alone has solved the problem.

Tax: two returns, always

Married couples are assessed jointly, their incomes added together and taxed as one. That produces the well-known marriage penalty for two high earners, and a benefit for couples with uneven incomes.

Unmarried couples are assessed individually. Two returns, every year, no exceptions.

Each of you declares your own share of what you own, your own share of any property value and imputed rental value, your own share of the debt, and each of you has your own cap on deductible debt interest. Two separate caps rather than one shared one is occasionally an advantage, and it is one of the few places where being unmarried is quietly the better deal.

The practical consequence is that "we" is not a tax unit. Whose name is on which account and which contract determines who declares what, and it is worth getting that deliberate rather than accidental.

If you own your home together

Buying together is where the missing rulebook costs the most, so this deserves care.

Fractional co-ownership is the usual form. Equal shares are presumed, but that presumption can be rebutted, and the quota entered in the land register is what actually governs. So if one of you contributed more, the land register is where that has to be recorded. A private agreement is worth having too, but the register is the document that decides.

Each share is a property in its own right. It can be sold, mortgaged, and seized separately, which is not what most couples picture when they say they bought a place together.

Then the part nobody plans for. Any co-owner may demand dissolution of the co-ownership at any time. If you cannot agree how, the court orders an auction, because a flat cannot be sawn in half. That is the default outcome of a breakdown, and it is why a written agreement covering who may buy the other out, on what basis, and in what timeframe, matters far more here than it does for a married couple who have a whole statutory process instead.

The mortgage is a separate trap. Towards the lender you are jointly and severally liable, meaning the bank can pursue either of you for the whole amount regardless of what you agreed between yourselves. And releasing one borrower from the loan requires the lender's consent. Not yours, not your partner's. Splitting up does not split the mortgage.

The joint account is not what you think

An Oder-Konto lets either of you withdraw the whole balance. That is a disposal right, not ownership. Being able to take the money does not make it yours, and the question of whose it actually is remains open.

More sharply: if one of you runs into debt enforcement, that partner's creditors can in practice have the whole balance frozen, including the part that came from the other's salary.

Keep the shared account for shared outgoings and keep your own savings in your own name. This is not distrust, it is just how the exposure works.

What about the pensions

Here the honest answer is that it depends on your fund, and that you have to go and look.

Some pension funds allow a member to designate a cohabiting partner as a beneficiary for survivor benefits. Many require the partnership to have lasted a minimum period, or to be registered with the fund in writing before death, and a designation made too late is worth nothing. Others do not offer it at all.

None of this is automatic. It is in your fund's own regulations, and the form, if there is one, has to be filed while you are alive to file it.

The same logic applies to a Pillar 3a account, where the beneficiary order is set by rules and by what you have designated with the provider. Ask your bank or insurer what you have on file, rather than assuming.

Two questions, two phone calls: does my fund allow a life-partner designation, and have I actually filed it.

What to actually do

Four things, and none of them requires a lawyer for the first pass:

1. Write a will. Without one your partner inherits nothing. This is the single highest-value hour in the list.
2. Ask your pension fund whether a life-partner designation is possible, and file it if it is.
3. Check your 3a beneficiary with the bank or insurer holding the account.
4. If you own property together, check the land-register quota matches what each of you actually put in, and write down what happens if you separate.

A notary is worth the money for the will and the property agreement, particularly if there are children from an earlier relationship or if the contributions were uneven. Two points in this area are genuinely contested among Swiss lawyers, so a notary is the right address for them rather than an article.

See it as one household

The awkward part of planning as an unmarried couple is that you live as one household and the system treats you as two strangers who happen to share an address. Two tax returns, two pension funds, two sets of rules, and one set of bills.

That is what SORVA models. You can plan both partners together, with separate careers and separate retirement ages, and see the household and the individual views side by side, taxed the way Swiss law actually treats you: jointly if you are married or in a registered partnership, individually if you are not. Create your plan at sorva.ch, free during the public beta.

Common questions

Does living together for long enough eventually count as marriage?

No. Switzerland has no common-law marriage. Ten years and a joint mortgage change nothing about your legal position.

Would registering our partnership help?

Registered partnership is available to same-sex couples and carries broadly marriage-like treatment. It is not a general-purpose option for every unmarried couple, so for most people reading this the choice is marriage or paperwork.

Is it better to marry, then?

That is a personal question with a tax answer that depends entirely on your two incomes, and this article cannot answer it for you. What it can say is that if you are not marrying, the paperwork above is what stands in for it.

Educational information, not financial advice. Figures are for 2026 and may change.