Selling an apartment building in Zurich: how buyers do the sums

Less than many fear. Every lease passes to the buyer together with ownership.¹ The Swiss saying is: a sale does not break a lease (Kauf bricht Miete nicht). Rent, notice and deposit stay unchanged.

The buyer gains just one extra option. If he urgently needs a flat for himself, close relatives or in-laws, he may give notice with the statutory period for the next statutory date.¹ In an apartment building this usually affects single flats, not the whole building. Even then the official form is required. The tenant can challenge the notice and ask for an extension, more time to move out.¹

One point affects you directly. If the buyer gives notice earlier than your lease with the tenant would have allowed, you are liable to her for the damage.¹ That is why the parties agree in the sale contract that the buyer fully steps into your legal position.⁴

What this means for you: your tenants do not lose their homes through the sale. One contract clause protects you.

Differently from a family house. Whoever buys an apartment building is mainly buying rental income. For such income properties, the bank therefore uses the earnings value (Ertragswert).⁸ This is the rental income that can be achieved over the long term, converted into a capital value. It is based on net rents, excluding service charges.⁸

The statistical comparison with sold homes, which banks use for family houses, fits poorly here. Two buildings of the same size can be worth very different amounts if the rents differ.

Nor can a buyer simply recover too high a price through higher rents. Rents based on a clearly excessive purchase price are abusive.¹ A price that holds up is therefore anchored in the rent.

Two official figures support your income. On 1 June 2026, only 0.52% of flats in the Canton of Zurich stood empty.¹⁰ The reference interest rate for rents has been 1.25% since September 2025.⁹

What this means for you: your most important document is a clean overview of the rents.

For a let building, the sale contract must settle what happens to every tenancy.⁷ The notary therefore needs an overview of the leases. In practice it is called a rent roll (Mieterspiegel): a list of all tenants with move-in date, rent and deposit. Operating cost statements and maintenance records also help.

Leases are not entered in the land register. Usually only the seller knows about them.⁵ A missing lease means missing income the buyer is paying for. For an apartment building, the official flat numbers also belong in the sale contract. The municipal building office provides them.⁵

You also need a current extract from the land register.² If a lease is registered there as a priority notice, it binds every new owner.¹ In the Canton of Zurich, building insurance continues automatically. The land registry reports the change of owner itself.⁴

What this means for you: a complete file shortens the buyer’s checks. The full list is in our guide to documents for selling a house.

In principle the same as for any house: property gains tax (Grundstückgewinnsteuer), the tax on the profit from a sale.³ In Zurich it rises in steps from 10% to 40% of the gain. It falls from five full years of ownership, to half after 20 full years.³ Very short ownership adds a surcharge.

For buildings held long, one rule helps. If the acquisition was over 20 years ago, the market value of 20 years earlier may replace the old price.³ Zurich has charged no transfer tax since 1 January 2005.⁶

A business asset, for example in self-employment, is different. Part of the gain then counts as income: as much as was written off earlier.³ Only the increase above that stays with property gains tax.¹⁷ For a privately held building, the whole gain is subject to property gains tax.

What this means for you: first clarify whether the building is private or a business asset. Your figure: the calculator for the Canton of Zurich.

The good news first: an existing oil or gas heating system may keep running. There is no duty to replace it while it works.¹⁴

The rule only applies on replacement. Since 1 September 2022, a new heating system in an existing building must run on renewable energy.¹⁴ This applies if it is technically possible and the lifetime costs are no more than 5% higher. Otherwise, at most 90% of the demand may come from non-renewable energy.¹⁴ The duty falls on whoever owns it at replacement.

A buyer plans for replacing a large central heating system. If the authority has granted a deferral because of financial hardship, this is noted in the land register.¹⁴ The deferral ends no later than three years after the next change of ownership, that is, your sale.¹⁴ In practice the duty therefore passes to the buyer.

What this means for you: disclose the age and condition of the heating from the start. What the buyer only discovers late quickly becomes an argument against the price.

That depends on the buyer, not on you. Buyers from abroad fall under the Lex Koller, the federal act on the acquisition of real estate by persons abroad.¹² For them, a purely residential building as a capital investment cannot be approved: the permit is refused.¹²

Citizens of the EU and EFTA who live in Switzerland are not persons abroad. The same applies to foreigners with a C settlement permit.¹² Conversely, a Swiss company counts as a person abroad if persons abroad control it. This is presumed if, for example, they hold over a third of the capital.¹²

If a required permit is missing, the contract has no effect. If in doubt, the land registry gives the buyer 30 days to get the permit or a ruling that none is needed.¹² The Federal Council wants to tighten the law. Nothing is decided yet.¹³

What this means for you: check who can buy before the notarisation, not afterwards. A commercial part used for the buyer’s own business may be assessed differently.¹²