The Global Minimum Tax in Switzerland: A Practical Guide for Affected Groups

The OECD global minimum tax is now in force in Switzerland. For calendar-year groups in scope for the 2024 fiscal year, the first Swiss filing falls due on 30 June 2026 — and even groups that ultimately owe no additional tax may still face registration, documentation, information-return or notification, and local-return obligations. This guide explains who is affected, what is now required, what it is likely to cost, and what happens if a group does nothing.

For several years, "Pillar Two" was discussed as a change that was coming. That phase is over. Since 1 January 2024, the OECD/G20 global minimum tax has been part of Swiss law, and it has created concrete, dated obligations: registration, calculation, an annual top-up tax return, an XML-based information return, local notifications, and the documentation needed to defend a safe-harbour position.

It helps to be precise about what this is. Pillar Two is not simply a tax on "low-tax structures." It is a new layer of tax compliance that reaches into financial accounting, group consolidation, transfer pricing, IT systems, M&A, intra-group agreements and management reporting. A group can fall squarely within scope, do everything correctly, owe no additional tax — and still carry a substantial filing and documentation obligation.

The first deadline for calendar-year groups is 30 June 2026, the due date for the 2024 reporting year. For groups with a non-calendar financial year, the first return is due 18 months after the end of the first relevant fiscal year, and 15 months after the end of each year thereafter. The rest of this guide works through the practical consequences for businesses with a Swiss footprint.

Pillar Two is designed to ensure that large multinational groups pay an effective tax rate of at least 15% in every jurisdiction where they operate. The test is applied jurisdiction by jurisdiction, not only at the level of the group as a whole.

The mechanics, in simplified form: for each jurisdiction the group calculates its GloBE income, its covered taxes and the resulting effective tax rate. Where that rate falls below 15%, a "top-up tax" arises to bring it up to the minimum. The calculation does not run off the headline cantonal corporate tax rate. It uses dedicated GloBE rules, with adjustments to accounting profit, deferred taxes, tax credits, a substance-based income exclusion and a series of safe harbours.

Three instruments deliver the result:

Pillar Two does not apply to every company. It applies to large groups. A group is in scope where its consolidated annual revenue reaches at least EUR 750 million in at least two of the four financial years immediately preceding the year under review. On the Swiss authorities' own estimate, around 99% of companies in Switzerland are not directly affected. In addition, under Swiss law a lower threshold may become relevant where the jurisdiction of the ultimate parent entity applies a lower threshold for its own IIR.

The crucial point for Swiss businesses is this: the size of the individual Swiss entity does not decide the question — the group does. A small Swiss GmbH or AG can be an in-scope constituent entity if it belongs to a group above the threshold.

In practice, the following situations should all be assessed:

To make this concrete, the table below maps the most common Swiss profiles to the question each needs to answer.

Before any calculation, management can run a quick triage. Seven questions usually reveal whether — and how — Pillar Two affects the group:

If the answer to the first two questions is yes, the group needs a structured response rather than a wait-and-see approach.

Switzerland introduced the OECD minimum tax on 1 January 2024. The electorate and the cantons approved the constitutional basis on 18 June 2023. The rules currently operate through an ordinance — the Ordinance on the Minimum Taxation of Large Groups of Companies (Minimum Taxation Ordinance, MindStV; SR 642.161, adopted 22 December 2023). Within six years, the Federal Council must submit federal legislation to Parliament to replace the ordinance.

The Swiss model today is as follows:

Two features deserve emphasis. First, Switzerland uses a one-stop-shop approach (One-Stop-Shop-Verfahren). Because the GloBE rules blend results by jurisdiction, the taxable Swiss constituent entity (steuerpflichtige Geschäftseinheit) is determined by the statutory order in the Ordinance — it is not chosen freely — and a single competent canton (zuständiger Kanton) assesses the top-up tax for the entire Swiss footprint, then distributes the revenue to the Confederation and the other cantons. Where the criteria are unclear or do not apply, the competent cantonal authority or the Federal Tax Administration determines the responsible entity, and the Swiss entities must appoint a joint representative.

Second, other Swiss constituent entities may remain jointly and severally liable for the tax up to the amount allocated to them, and the Swiss supplementary tax is not deductible for federal or cantonal profit tax purposes. That matters for the intra-group recharge: the tax must be allocated economically among the Swiss companies, and it cannot be treated as an ordinary deductible charge.

This is where many internal summaries are now out of date. The framework has moved several times in the last year, and the most recent changes are the ones most likely to be missed.

The OECD announced a package agreed by a large number of jurisdictions, containing simplifications, safe harbours, an approach to tax incentives, and confirmation of the QDMTT as the primary mechanism. The political uncertainty for many groups has fallen. The data and systems burden has not.

On 7 April 2026 the Swiss Federal Tax Administration confirmed that the safe harbours under the side-by-side package may be applied in Switzerland, subject to conditions, from defined dates. The Transitional Country-by-Country Reporting Safe Harbour has been extended for fiscal years beginning no later than 31 December 2027 and ending no later than 30 June 2029, subject to the applicable conditions, including the "once out, always out" principle. The Simplified Effective Tax Rate Safe Harbour may be applied for financial years beginning on or after 31 December 2025. The Substance-based Tax Incentive Safe Harbour, the Side-by-Side Safe Harbour and the UPE Safe Harbour may be applied for financial years beginning on or after 1 January 2026.

Under the Side-by-Side Safe Harbour, eligible US-parented groups may be relieved from IIR and UTPR exposure in respect of their domestic and foreign profits from 2026, subject to the applicable conditions and to the Central Record mechanics. This does not remove local domestic top-up taxes, including the Swiss QDMTT, and it does not remove the Swiss registration, information-return or notification analysis. For a Swiss subsidiary of a US group, the Swiss supplementary tax computation continues to apply, and the practical questions remain: does a Swiss top-up tax arise, who files and notifies, and does the group qualify for the safe harbour? Nil exposure should never be assumed without first checking eligibility.

Switzerland signed the multilateral agreement for the automatic exchange of GloBE information (the GIR MCAA) in 2025. The agreement has been provisionally applied in Switzerland since 1 January 2026 and is expected to be ratified in mid-2026 following final approval. For the first time, in-scope groups may file a GloBE Information Return with the Federal Tax Administration for the 2024 fiscal year. Whether central filing relieves a Swiss entity from local filing depends on the filing jurisdiction and on the activated exchange relationship. A useful point for Swiss directors and officers: filing the information return in accordance with the GloBE Model Rules does not require an authorisation under Article 271 of the Swiss Criminal Code.

In May 2026 the implementing jurisdictions reached a common understanding: where the information return is filed centrally in a jurisdiction whose system is operational, jurisdictions will use their domestic mechanisms to waive penalties or suspend enforcement of local filing obligations, provided the return has been filed centrally before the relevant exchange deadline. This is not a general filing exemption. It protects against the consequences of delayed exchange relationships only where central filing, the required notifications and the relevant exchange-framework conditions are all satisfied.

The OECD's January 2025 guidance on Article 9.1 governs how certain deferred tax assets — those arising from tax benefits, elections or arrangements in place before Pillar Two, in particular after 30 November 2021 — are taken into account in the effective tax rate. It can reduce the recognition of those assets and so increase the Swiss top-up tax for 2024. Following two parliamentary motions, the Federal Council opened a consultation on 6 May 2026 — running until 14 July 2026 — on amending the Ordinance so that this guidance applies in Switzerland only from the 2025 financial year, deliberately diverging from the OECD model rules. Until the Federal Council decides, the position of the Federal Tax Administration is clear: the guidance and its grace-period limitation apply under current law; returns must be filed on time, with no deadline extension; and a remark is required where the grace-period limitation reduces the effective tax rate.

Clients should also understand the political backdrop. In May 2026 a study by the University of St. Gallen, commissioned by the Swiss-American Chamber of Commerce, argued that Switzerland should repeal its QDMTT and IIR and replace them with a separate domestic minimum tax, citing limited global adoption, the US exemption and litigation risk. This is a policy argument, not a change in the law, and it is not the position of the Federal Council. The longer-term direction of Swiss policy is not settled, and groups should avoid assuming the present rules are permanent. For current compliance purposes, however, this debate does not change any registration, filing, payment or documentation obligation.

Safe harbours can remove the need for a full GloBE calculation in a given jurisdiction — but each carries conditions, and none is automatic. The table below summarises the main routes confirmed for Switzerland.

A safe-harbour position should be treated as an evidentiary file, not as a label. The file should show the source data, the test applied, the fiscal year covered, the election made, the person approving it, and the reason why no disqualifying arrangement or "once out, always out" issue arises.

The obligations break down into a small number of discrete tasks. Treated as a project, they are manageable. Left until June, they are not.

For most groups the binding constraint is data, not analysis. A workable data pack includes:

• the group structure chart and the consolidation perimeter;
• a list of all constituent entities, permanent establishments and joint ventures;
• the consolidated financial statements and the local financial statements;
• the CbCR data and its reconciliation to the consolidation;
• current tax expense, deferred tax expense and deferred tax assets and liabilities;
• covered taxes by entity and by jurisdiction;
• tax credits, grants, patent box relief, R&D incentives and other reliefs;
• payroll and tangible-asset data for the substance-based income exclusion;
• ownership changes, restructurings and M&A in the relevant years;
• hybrid arrangements entered into after 18 December 2023;
• elections and safe-harbour workpapers;
• XML validation evidence and filing receipts.

Hybrid arrangements entered into after 18 December 2023 are specifically sensitive under the Swiss application of the guidance and should be identified early.

For many finance teams, an audit issue lands harder than an abstract OECD reform. Pillar Two belongs inside the year-end close, not beside it.

• Pillar Two affects current tax expense, provisions, disclosures and management representations.
• Under IFRS, the IASB introduced a mandatory temporary exception from recognising and disclosing deferred taxes arising from Pillar Two, together with targeted disclosure requirements. Current Pillar Two tax is still recognised and disclosed.
• Swiss statutory financial statements must still reflect actual liabilities, recharge arrangements and provisions where appropriate.
• Auditors will ask for the scope memo, the safe-harbour support, the GIR filing approach, the Swiss QDMTT calculation and a management representation.

Because the Swiss supplementary tax is assessed through one Swiss taxable entity but economically relates to the Swiss jurisdictional result, the group should document how the burden is recharged among the Swiss constituent entities, and the recharge should follow the allocation of the top-up tax.

A waiver of the recharge, or a recharge that does not follow that allocation, can create separate Swiss tax consequences — including potential hidden-distribution and withholding-tax issues. The recharge mechanics should therefore be documented before the first filing, not after assessment, and the analysis should be confirmed for the specific group.

Inaction is not a saving. More often, it is a loss of control.

First, the tax does not disappear. Depending on the group structure and the jurisdictions involved, if Switzerland does not collect the QDMTT, the top-up may be collected through the IIR in the parent jurisdiction or, in future, through the UTPR elsewhere. Passivity often simply hands the revenue to a foreign treasury.

Second, there are penalties. The Ordinance provides for sanctions that include, among others:

• an administrative charge of up to CHF 200 per day for a late information return, capped at CHF 50,000 — this is an administrative sanction, not a criminal fine;
• up to CHF 100,000 for a false or incomplete information return;
• up to CHF 10,000 for failure to comply with official orders;
• up to CHF 1,000 for procedural violations, and up to CHF 10,000 in serious or repeated cases;
• for top-up tax evasion, a fine geared to the amount of tax evaded, with scope for reduction or increase.

Persons who intentionally instigate, assist in or participate in an evasion or procedural offence can themselves be fined up to CHF 10,000 — and up to CHF 50,000 in serious or repeated cases — and may be jointly and severally liable for the evaded tax. In serious cases, the Ordinance also contains a tax fraud offence, where evasion is committed using false, falsified or substantively incorrect documents; this can lead to imprisonment of up to three years or a monetary penalty.

There is transitional relief. The Ordinance provides for a waiver of the administrative charge for a late information return, and of negligence-based procedural and evasion penalties, for financial years beginning on or before 31 December 2026 and ending on or before 30 June 2028. This relief should not be read as permission to do nothing. It does not cover intentional misconduct, it does not remove the tax itself, it does not remove the obligation to register and file, and it does nothing for the commercial, audit and international exposure that a group still carries.

Third, a group can lose a safe harbour. A late or defective process may not always be the legal reason a safe harbour fails. The practical risk is that the group cannot evidence the required conditions, makes an inconsistent election, relies on defective CbCR data, or falls foul of the "once out, always out" principle — and is then left with the full GloBE calculation.

Fourth, there is M&A and financing risk. A buyer will ask about Pillar Two exposure. A bank may require a compliance representation. An auditor may require a provision, a disclosure or a management representation. A group without a prepared file pays for that gap in valuation, in the warranty catalogue and in the timeline of the transaction.

Pillar Two changes the economics of tax incentives. A relief that reduces the tax base — a patent box, an R&D super-deduction, a tax holiday or another cantonal or federal incentive regime, where applicable — can, for a large group, simply lower the effective rate and trigger a top-up tax that captures the saving. The advantage that was once obvious may now be neutralised.

Not every incentive behaves this way. Qualified refundable tax credits, qualified marketable transferable credits, substance-based incentives and certain grants can retain their value, and the OECD framework deliberately treats substance-based incentives more favourably than base-reducing relief. Some cantons are reviewing or adapting their tax policy in response to Pillar Two, including rate levels and substance-based or grant-style incentives; this should be assessed canton by canton.

The practical shift is one of mindset. The planning question is no longer "where is the rate lowest?" It is "what is the after-Pillar-Two cash tax cost, taking account of substance, credits, grants and the compliance burden?"

In a transaction, Pillar Two has become part of the tax due-diligence request list. On a Swiss target, expect questions such as:

• Is the target group in scope today?
• Was it in scope historically?
• Is the Swiss target a constituent entity of an in-scope seller group?
• Who files the GIR for pre-closing years?
• Who bears the Swiss QDMTT for straddle periods?
• Are the safe harbours documented?
• Are the Article 9.1 deferred-tax positions known?
• Are the patent box, R&D or grant positions affected?
• Are tax warranties, indemnities and cooperation covenants included?
• Does the buyer have access to the seller's CbCR and GIR data after closing?

The share purchase agreement should allocate responsibility for pre-closing GIR filings, the Swiss top-up tax and post-closing cooperation. A target without a prepared Pillar Two file slows the deal and weakens its negotiating position.

For most groups, the larger cost is not the legal opinion — it is the data. Extraction from the ERP, mapping to the GloBE data points, reconciliation with country-by-country reporting, deferred-tax computations, XML generation, internal review and the audit trail together account for the bulk of the effort.

The figures below are indicative, market-oriented budget ranges only — not a quote. They exclude VAT, external auditor fees, foreign counsel, software licences and any major ERP implementation, and they assume the group can provide reasonably complete accounting and tax data. Actual cost depends on the number of jurisdictions, the number of Swiss constituent entities, the quality of the data, the presence of incentives, safe-harbour eligibility, M&A, permanent establishments, the accounting standard, and whether the parent prepares a central information return. Where a foreign parent runs the calculation and the GIR well, a Swiss subsidiary may need only a local review and a notification, and can fall below the lower end of the range; where the parent is poorly organised, even a small Swiss company can cost more because of data remediation.

For large groups, Pillar Two in Switzerland is an operating obligation, not a theoretical OECD reform. The most common — and most costly — mistake is to assume that, because no additional tax will be payable, nothing needs to be done. In practice, even a nil position can require scoping, registration, safe-harbour documentation, the information return or a notification, and defensible data.

The right approach for a Swiss group is straightforward: confirm scope quickly, register on OMTax in good time, document the safe harbours, re-model the incentives, and make sure the Swiss return, the information return and the group-level reporting all tell the same story.

Goldblum and Partners AG advises Swiss-headquartered groups and the Swiss members of foreign groups across the full Pillar Two lifecycle: from scoping and OMTax registration, through the Swiss top-up tax return, the GloBE Information Return and safe-harbour documentation, to the structuring, incentive and M&A questions that the global minimum tax now raises. We work alongside in-house tax teams, auditors and foreign advisers, and we focus on a defensible Swiss position that is consistent with the group's reporting elsewhere.

If your group has a calendar financial year and may be in scope for the 2024 reporting year, the 30 June 2026 deadline leaves little time. To discuss your position, contact our tax team via goldblum.ch.

This guide is based on official and primary sources, including:

• Swiss Federal Tax Administration — Top-up tax / Ergänzungssteuer (threshold, rate, ordinance, IIR from 2025)
• Swiss Federal Tax Administration — Top-up tax declaration (electronic filing via ePortal)
• Swiss Federal Tax Administration — Legal basis / Minimum Taxation Ordinance (MindStV, SR 642.161)
• Swiss Federal Tax Administration — Official statements on the top-up tax, including the statement of 7 April 2026 on the side-by-side safe harbours
• Swiss Federal Tax Administration / Federal Council — consultation of 6 May 2026 on the Minimum Taxation Ordinance (Article 9.1 deferred-tax question)
• Federal Department of Finance (EFD) — Implementation of the OECD minimum tax rate in Switzerland (policy, UTPR, revenue split, cantonal measures)
• State Secretariat for International Financial Matters (SIF) — GloBE Information Return (GIR), central filing, the GIR MCAA and the Article 271 SCC point
• OECD — Global Minimum Tax, the consolidated commentary and the side-by-side package
• OECD — Common understanding of implementing jurisdictions and further administrative guidance (18 May 2026)
• IASB / IFRS Foundation — International Tax Reform: Pillar Two Model Rules (amendments to IAS 12), temporary deferred-tax exception and disclosures
• OMTax (Swiss Tax Conference / SSK) — the joint cantonal web application, available since 2 January 2025