Selling a tenanted property

If you sell a tenanted property, the tenancy passes to the acquiring party together with ownership. The tenants keep their agreements without having to consent and without new ones being concluded. The buyer steps into what you signed – which is why the tenancy agreements in the original are among the most important sales documents.

The new owner takes over the agreements with their notice periods and can give ordinary notice like any landlord. Early notice, i.e. without regard to the contractual term and notice periods, can be given for residential and commercial premises only in the case of urgent personal need (dringender Eigenbedarf) for the owner, close relatives or relatives by marriage, and then with the statutory notice period to the next statutory termination date. For flats that is three months. Formal defects render the notice void, it can be challenged in any case, and a tenancy for residential premises can be extended by up to four years.

If the new owner gives notice earlier than the agreement would have allowed you to, it is not the new owner but you who is liable to the tenants for the resulting loss. That is not a detail: it is the reason for disclosing all contractual terms to the buyer – fixed terms, waivers of termination, tenancies entered as priority notices in the land register.

Neither on an ordinary sale nor on conversion into condominium ownership (Stockwerkeigentum) do the tenants have a pre-emption right (Vorkaufsrecht) by operation of law. Not even condominium owners have one against third parties unless it was agreed in the deed of constitution (Begründungsakt) or later and entered as a priority notice in the land register. A contractual pre-emption right with a predetermined price requires notarisation, one without a fixed price only written form. It appears in the land register extract only if it has been entered as a priority notice; arrangements that have not been so entered must be looked for in the tenancy agreements.

Since the popular vote of 2021, Basel-Stadt has had housing protection rules that apply for as long as there is a housing shortage – defined by law as a vacancy rate of 1.5 per cent or less. At 0.78 per cent most recently, they are in force. The Housing Protection Ordinance (Wohnraumschutzverordnung) was comprehensively revised with effect from 1 November 2025; accounts from earlier years are partly out of date.

The rules cover existing rental housing in properties with more than three flats that can be rented for more than three months. Excluded are properties with three or fewer rented flats, as well as luxury flats and single-family houses with six or more rooms. At exactly three as against four flats the legal position tips over – on a sale, that is one of the first questions.

The sale itself does not require a housing protection permit. What must be approved are building projects and the creation of condominium ownership, not the transfer of ownership. The decisive point is what the buyer intends to do afterwards.

Anyone who renovates beyond simple ordinary maintenance must notify this or have it approved: without a rent increase, a notification is sufficient; with an increase, a permit is required. Simple maintenance means investments of up to CHF 5,000 per flat and calendar year, provided no rent increase is claimed. In the simplified procedure, the increases that can be passed on are limited: CHF 0 to 80 a month for one to two rooms, 0 to 120 for three, 0 to 160 for four rooms or more.

And since the revision, the rule for the calculation is that, as a general rule, only 40 per cent of the adjusted investments count as value-enhancing. Renovation is still permitted – it is just that less can be passed on than many an investment calculator assumes.

Where renovation, conversion or replacement was carried out with a permit, the rents are subject to official control for five years – and this is annotated in the land register. Anyone who has renovated with a permit in the last five years is therefore selling a property with a visible rent restriction. The buyer sees it in the extract; a later change in the law gives the buyer no claim to an adjustment.

From four flats upwards, the creation of condominium ownership requires a permit in times of housing shortage. The owner must prove that the entire property is of a standard appropriate for condominium ownership; the competent office examines this within four months. Anyone who offers a property as “suitable for condominium ownership” without having the permit is selling an expectation, not a legal position.

Two widespread accounts are incorrect. There is no longer a cantonal right of return for tenants after a renovation – the Federal Supreme Court set aside the relevant provision in December 2022 as contrary to federal law. And the law contains no ban on giving notice to all tenants in order to empty a building: protection against termination is governed by federal law. The canton controls the permit for the building project and the permissible rent afterwards, not the termination itself.

Basel-Landschaft has no housing protection act, no rent control after renovation and no permit requirement for renovation, conversion, demolition or the creation of condominium ownership. For a tenanted property in Binningen, different rules therefore apply than for one in Basel – for an otherwise comparable property. Federal tenancy law of course applies equally in both cantons.

The tenants must permit viewings in so far as they are necessary for the sale. They must be announced in good time, and the tenants' interests must be taken into account; rent reduction and damages remain reserved. The law does not specify a fixed number of days – anyone who reads a number is reading a guide, not the law. As managing agents we have this side on the telephone every day and know what a badly announced viewing can do.

Rent deposits must be placed with a bank in an account in the tenant's name, for residential premises no more than three months' rent. They are released with the consent of both sides, on the basis of a legally binding payment order (Zahlungsbefehl) or a judgment, or to the tenants if the landlord has not asserted a claim by legal means one year after the end of the tenancy. And important for the buyer: in Basel-Stadt the mandatory form for the initial rent (Formularpflicht) currently applies – every new letting requires the cantonal form stating the previous rent, which can be challenged within 30 days.