As a result, MNEs should prepare for the following rules to apply to their Swiss entities. This includes understanding how to collect the relevant data and implementing the necessary compliance measures:  

• Domestic top-up tax and income inclusion rule (IIR): likely to be applicable for business years beginning on or after 1 January 2024 (or even 31 December 2023 to be in line with the EU).
• Qualified domestic top-up tax (QDMTT): likely to be applicable as of next year.
• Undertaxed profits rule (UTPR): likely to be applicable for business years beginning on or after 1 January 2025 (or 31 December 2024).

The potential effects of these rules should already be taken into account for intra-group reorganizations and M&A transactions (in particular in the case of acquisitions, but also in the case of disposals).

What comes next?

The timeline for implementation in Switzerland will be mainly aligned with the implementation in the other jurisdictions, including approximately 140 countries, especially EU member states., resulting in the not yet certain entry-into-force dates mentioned above. This aims to  ensure that Switzerland does not lose any portion of its tax base in favor of other countries.

Initially, the GloBE rules will be temporarily implemented by way of an ordinance. The Swiss parliament will subsequently enact a federal law to replace the ordinance in the coming years.

The ordinance will also cover various procedural aspects:

• Digitalization: The declaration and the procedure are to be completed electronically on a portal. The Federal Tax Administration and the cantons concerned will have access to this portal.
• Minimization of administrative burden: The administrative burden for the entities concerned shall be minimized by implementing of a so-called "one-stop shop" for levying the supplementary tax. The economically most important unit within a group of companies will pay the tax in its home canton on behalf of all units across Switzerland. Economic importance is measured by operational profit, and in the absence of profit, by equity. This canton shall then transfer to the Confederation, and to those cantons in which the other business units of the group are resident, their share of the revenue from the supplementary tax. Nonetheless, the taxable business units are obliged to cooperate by submitting a self-declaration via the digital portal.
• Specifics in the appeal process: The appeal procedure provides for assessment appeals to be submitted directly to the Federal Administrative Court, i.e. skipping the usual first instance of appeal at the assessing tax administration. It is important to note that there is also an appeal possibility for the cantons affected by the supplementary tax assessment, (i.e. the appeal rights are not reserved only for taxpayers).
• Non-compliance: The fines etc. for non-compliance are expected to be less severe compared to other jurisdictions, amounting to up to CHF 10'000 (except in cases of tax evasion, where significantly higher fines will apply).

It should be noted that the supplementary tax cannot be deducted from the tax basis (in contrast to Swiss corporate income tax, but in line with OECD principles), and that all Swiss entities will be jointly liable for the payment of the supplementary tax.

Further, following the certainty brought by the referendum, the focus of the Confederation as well as the cantons impacted (in particular those with an ETR <15%) will be on how to maintain their local attractiveness as favorable business destinations (e.g., by means of introducing Qualified Refundable Tax Credits or related initiatives).