Minimum taxation in Switzerland – What are the obligations for companies?

Since January 1, 2024, the introduction of minimum taxation in Switzerland has created new tax and administrative obligations for international corporate groups.

After exploring the general framework of this reform in our first article (discover it here), let us remind that:

The Qualified Domestic Minimum Top-up Tax (“QDMTT”) applies for the first time to fiscal years beginning on January 1, 2024.
The Income Inclusion Rule (“IIR”) will apply to fiscal years beginning on January 1, 2025.

This article outlines the main obligations for companies in Switzerland, including mandatory registration and cantonal requirements already in force for the 2024 tax year.

Corporate obligations in Switzerland

Companies are subject to new requirements following the introduction of minimum taxation, under the Minimum Taxation Ordinance ("OTMin").

Registration requirement

According to article 19 OTMin, companies subject to the top-up tax must register via the OECD Minimum Taxation (OMTax) application, developed by the Swiss Tax Conference.
Registration is possible starting January 1, 2025, and must be carried out voluntarily, without any prior request from the tax authorities. It should be noted that, as of today, OMTax is only available for the QDMTT (Qualified Domestic Minimum Top-up Tax). The module for the IIR (Income Inclusion Rule) declaration, which comes into effect one year after the QDMTT, will be available on OMTax starting January 1, 2026. The OMTax platform enables:

the registration of the relevant constituent entity,
the online submission of the tax declaration,
the assessment of the top-up tax

The obligation applies to all Swiss entities that are part of a group subject to minimum taxation, i.e. a group that has annual revenues of EUR 750 million.
A single entity may register on behalf of all Swiss group entities, provided that all are explicitly mentioned in the procedure.
Registration is a mandatory step before filing the tax return and enables the tax authorities to identify and monitor potentially affected groups.

Le dépôt de la déclaration

In accordance with article 20 OTMin, once the constituent entity is registered, it must submit its top-up tax declaration to the relevant cantonal tax authority:

within 18 months of the end of the first applicable fiscal year;
then within 15 months for each subsequent fiscal year.

If the declaration is not submitted on time or the documentation is incomplete, a fine of up to CHF 10,000 may be imposed (art. 29 OTMin). In practice, the authorities generally allow entities to regularize their situation before applying any penalties.

Anticipated measures by the cantons

Alongside the federal framework, certain cantons have already introduced measures to anticipate the implementation of minimum taxation. These initiatives are mainly intended for preparatory and statistical purposes.
Here are a few examples of specific cantonal actions:

Geneva: Swiss constituent entities subject to minimum taxation must indicate their status in their 2024 tax return, even if no tax is yet due. This requirement is solely intended to identify the relevant groups for statistical purposes.
Vaud: The Cantonal Tax Administration has sent targeted letters to potentially affected companies. These letters explain how to register on OMTax and request additional information to assess the financial impact of the reform—both for companies and for the canton.

At RSM Switzerland, we support numerous Swiss and international groups in understanding and implementing these new obligations.

Feel free to contact us for assistance.

Source : Top-up Tax