With the amendment to the ordinance, which comes into force on 1 October 2025, the Federal Council is responding to ongoing criticism of the lack of transparency in the determination of the initial rent. The most recent values of the reference interest rate and the national consumer price index must now be shown on the form for new lettings in cantons where forms are mandatory.
The aim is to make it easier for tenants to recognise whether a rent is justified or contestable. This not only increases confidence in the rental housing market, but also makes it easier for investors and institutional landlords to plan ahead.
Urban centres are particularly affected
The change affects cantons with mandatory forms such as Zurich, Geneva, Basel, Lucerne and Zug. These are regions in which the majority of new tenancies are concluded. There, the official and private forms must be adapted and approved by 1 October 2025 at the latest. Failure to do so could result in the tenancy agreement being classed as invalid with regard to the initial rent. This is a legal risk that professional property owners should not ignore.
At the same time, the Federal Council is easing the administrative burden for graduated rents. A simple written notification of the rent increase is now sufficient; an official form is no longer required.
Foundation for a future-proof rent model
The existing calculation model for rent adjustments, which dates back to the 1980s, is to be fundamentally revised. This is a political response to studies that judge the current model to be outdated. In future, the focus will be on realistic cost assumptions for capital, maintenance and administration, another development that is particularly important for institutional investors and project developers.
