In September 2024, the Federal Council had already decided to implement the Income Inclusion Rule (IIR) – an international supplementary tax – effective from 1 January 2025. This international supplementary tax extends the Swiss supplementary tax that was already introduced in 2024. Together, the two taxes are intended to ensure that the tax revenues generated by the new OECD minimum taxation are retained inside Switzerland rather than being expatriated. The federal government’s projected tax collection is predicted to range from CHF 1.5 billion to CHF 3.5 billion. According to the Federal Council press release of 20 November 2024, these sums could be skimmed off by foreign countries if Switzerland failed to implement the minimum taxation. Simultaneously, implementation shall guarantee legal clarity and safeguards the relevant company groupings against supplementary tax actions in other jurisdictions.

To implement the IIR in Switzerland by 1 January 2025, the Federal Council resolved on 20 November 2024 to revise the Ordinance on the Minimum Taxation of Large Enterprise Groups (Minimum Taxation Ordinance).