Deductibility of Interest in LBOs: Clarifications from the Swiss Federal Supreme Court

Introduction to LBOs and Tax Implications

A leveraged buyout, commonly known by its English acronym LBO (Leveraged Buy-Out), is a financial strategy frequently used to acquire a company primarily through borrowed funds. In Switzerland, this practice is particularly widespread among SMEs and large corporations. However, it raises complex tax questions, especially regarding the deductibility of interest on debt incurred to finance the acquisition.

In this article, we analyze the tax implications of LBOs in Switzerland, based on recent rulings by the Federal Supreme Court and clarifications from the Federal Tax Administration (source: Swiss tax system: Overview). We will also address the risks of requalification, secondary tax adjustments, and best practices for optimizing the tax structure of an LBO.

Recent Legal Clarification: Federal Supreme Court Ruling 9C_606/2025 of 24 February 2026

In its ruling 9C_606/2025 of 24 February 2026, the Swiss Federal Supreme Court addressed a key question for LBO transactions involving a "debt push down": whether interest on acquisition debt transferred to the target company through a downstream merger is tax-deductible.

Facts of the Case

A Swiss company (A. SA), which primarily owned a rental property, was acquired by an acquisition vehicle (C. SA) financed through a bank loan covering both the share purchase and the renovation of the property. Shortly after the acquisition, a downstream merger was carried out: C. SA was absorbed by A. SA, which inherited the acquisition loan on its balance sheet.

The Geneva tax authorities split the loan based on the allocation of funds: only interest corresponding to the renovation portion (approximately 24%) was accepted as deductible, while interest related to the share acquisition (approximately 76%) was denied.

Decision of the Federal Supreme Court

The Federal Supreme Court upheld the cantonal administration's position, relying on Art. 58 para. 1 let. b of the Federal Act on Direct Federal Tax (LIFD/DBG):

• Commercial justification principle: An expense is only deductible if it has an objective causal link with the commercial activity of the taxed company.
• Acquisition debt vs. operational debt: Debt incurred to acquire the company's own shares, subsequently transferred via a downstream merger, does not rest on a commercially justified reason at the level of the absorbing company — it benefits the acquiring shareholders, not the target company.
• No reliance on the tax evasion doctrine: The denial of the deduction was not based on an anti-abuse construction but solely on the strict application of the commercial justification principle ("Geschäftsmässige Begründetheit").

What This Ruling Changes in Practice

1. End of the doctrinal debate: This ruling definitively settles the question of interest deductibility following a "debt push down" via downstream merger, confirming a restrictive approach.
2. Only partial deductibility: Only the portion of the debt effectively allocated to the target company's operations (here, property renovation) remains deductible. The share acquisition portion is systematically excluded.
3. LBO structuring must be rethought: Practitioners must anticipate that structures relying solely on a post-merger "debt push down" will no longer allow acquisition interest to be deducted at the target level.
4. Greater legal certainty: By basing its decision solely on the commercial justification criterion (Art. 58 LIFD), the Federal Supreme Court provides a clear and predictable framework, without resorting to the tax evasion doctrine.
5. Impact on due diligences: Acquirers must now factor this constraint into their financial models and profitability analyses when structuring an LBO.

These clarifications reinforce the importance of structuring LBOs in compliance with legal and tax requirements.

'Debt Push Down' Effect: Deductibility of Interest under the LIFD

The "Debt Push Down" effect is a common practice in LBOs, where the acquisition debt is transferred to the target company. This strategy allows interest to be deducted at the operating company level, thus reducing its taxable base.

Conditions for Deductibility

1. Economic justification: The transfer of debt must be justified by valid economic reasons.
2. Compliance with admissible rates: Interest must comply with the maximum rates set by the Federal Tax Administration (source: Attention on intra-group loans and admissible rates).
3. Rigorous documentation: Loan agreements and financial flows must be clearly documented.

Numerical Example

• Acquisition amount: CHF 10,000,000
• Annual interest rate: 3%
• Annual interest: CHF 300,000
• Tax savings (tax rate of 15%): CHF 45,000

In this example, the deductibility of interest allows for significant tax savings, but only if all legal conditions are met.

Tax Audit and Risk of Requalification

Swiss tax authorities closely monitor LBOs to detect potential abuses. A tax audit can lead to the requalification of interest, resulting in significant financial consequences.

Main Risks

• Requalification as dividends: Interest may be requalified as non-deductible dividends.
• Fines and penalties: In case of non-compliance, fines may be imposed.

How to Protect Yourself?

• Maintain complete and accurate documentation.
• Consult tax experts to validate the LBO structure.
• Conduct regular internal audits to identify potential risks.

Compatibility with Withholding Tax and Secondary Tax Adjustments

Withholding tax is another essential component to consider in the context of LBOs in Switzerland. Intra-group financial flows, especially interest payments, may be subject to this tax (source: Federal Tax Administration (withholding tax)).

Points to Monitor

• Compliance with interest rates: Rates must comply with the guidelines of the Federal Tax Administration.
• Correct declaration: Any omission or error in the declaration may result in penalties.

Impact for Holdings and Practical Advice

Holdings often play a central role in LBOs. However, they must comply with specific rules to benefit from interest deductibility.

Practical Advice

1. Optimize group structure: A well-designed structure can maximize tax benefits.
2. Anticipate audits: Be prepared to justify every aspect of the transaction.
3. Work with experts: Experienced tax advice is essential to navigate the complexities of LBOs.

Considerations for SMEs and Large Companies in Switzerland

The tax implications of LBOs vary depending on the size and structure of the company.

SMEs

• Advantages: SMEs can use LBOs to finance their growth.
• Risks: SMEs are often less prepared for tax audits, which can lead to penalties.

Large Companies

• Advantages: Large companies generally have sufficient resources to structure complex LBOs.
• Risks: Complex structures may attract increased attention from tax authorities.

Steps to Structure a Compliant LBO

1. Preliminary analysis: Assess the economic viability of the LBO.
2. Structure design: Define the legal and financial structure.
3. Tax validation: Consult experts to verify tax compliance.
4. Implementation: Finalize contracts and financial agreements.
5. Monitoring and audit: Set up control mechanisms to ensure ongoing compliance.

Common Mistakes and How to Avoid Them

Common Errors

• Insufficient documentation: Lack of evidence to justify financial flows.
• Non-compliance with admissible rates: Use of excessive interest rates.
• Artificial structures: Creation of tax arrangements without economic justification.

Solutions

• Maintain comprehensive documentation.
• Check interest rates against official guidelines.
• Avoid artificial structures and favor economically justified solutions.

FAQ Interest Deductibility for Parent Companies

1. What is an LBO? An LBO is a company acquisition transaction financed mainly by debt.

2. Is interest always deductible? No, deductibility depends on meeting several conditions, including a clear economic link and compliance with admissible rates.

3. What is 'Debt Push Down'? It is a strategy where acquisition debt is transferred to the target company to benefit from interest deductibility.

4. What are the tax risks of an LBO? The main risks include requalification of interest as dividends and penalties for non-compliance.

5. How to avoid tax penalties? By maintaining rigorous documentation, complying with admissible rates, and consulting tax experts.

6. Can SMEs benefit from LBOs? Yes, but they must be particularly vigilant regarding tax and legal requirements.

Conclusion

LBOs offer interesting opportunities for Swiss companies, but they come with significant tax challenges. By following best practices and complying with legal requirements, companies can minimize risks and maximize the benefits of this financial strategy.

LBO Tax Optimization: Advanced Strategies

To maximize the tax benefits of LBOs while complying with Swiss regulations, it is essential to implement advanced tax optimization strategies. These strategies help reduce the risk of requalification and improve the overall profitability of the transaction.

International Structuring

In a globalized context, many Swiss companies involved in LBOs adopt international structures to optimize their taxation.

Advantages of International Structures

• Reduction of tax costs: By leveraging bilateral tax treaties, it is possible to reduce withholding taxes on interest payments.
• Financial flexibility: International structures allow better management of cash flows.

Points of Caution

• Compliance with BEPS rules: Structures must comply with OECD recommendations on base erosion and profit shifting (source: OECD tax models and Swiss adjustments).
• Cross-border documentation: Intra-group transactions must be justified by solid transfer pricing agreements.

Use of Hidden Reserves

Hidden reserves, often present in the balance sheets of Swiss companies, can be used to optimize the financial structure of an LBO.

How to Leverage Hidden Reserves?

1. Revaluation of assets: Identify undervalued assets in the target company's balance sheet.
2. Value creation: Use these reserves to strengthen the equity of the acquired company.
3. Debt reduction: Reinvest the released funds to reduce the amount of acquisition debt.

Advantages

• Reduction of the debt ratio.
• Improved perception by investors and creditors.

Key Steps for Successful Tax Due Diligence

Tax due diligence is a crucial step to identify risks and opportunities related to an LBO. Thorough analysis allows for anticipating potential tax issues and structuring the transaction accordingly.

Main Areas of Analysis

1. Analysis of existing debts

• Identify debts already present in the target company.
• Assess their impact on the company's ability to support new debt.

2. Review of intra-group financial flows

• Check the compliance of applied interest rates.
• Ensure financial flows are properly documented.

3. Verification of tax risks

• Identify risks of requalification of interest.
• Analyze the implications of secondary tax adjustments.

4. Asset evaluation

• Examine asset valuation to detect possible hidden reserves.
• Check the compliance of applied depreciations.

Checklist for Effective Tax Due Diligence

• Collect all relevant financial and tax documents.
• Analyze existing and planned loan agreements.
• Check the compliance of interest rates with tax guidelines.
• Identify risks of requalification of financial flows.
• Assess the implications of international tax treaties.
• Collaborate with tax and business law experts.

Case Study: Successful LBO in Switzerland

To illustrate best practices, let's look at a concrete example of a successful LBO in Switzerland.

This case highlights the importance of rigorous planning and close collaboration with experts to maximize tax benefits.

Additional FAQ on LBOs and Taxation in Switzerland

7. What are the most common mistakes in an LBO? Common mistakes include insufficient documentation, non-compliance with admissible interest rates, and the use of artificial structures without economic justification.

8. How do Swiss tax authorities detect abuses in LBOs? Authorities analyze financial flows, applied interest rates, and the economic justification of the structures in place. Any inconsistency may lead to a thorough audit.

9. Are LBOs suitable for financially distressed companies? No, LBOs require sufficient repayment capacity. Financially distressed companies may not be able to bear the debt burden.

10. What are the tax benefits of LBOs for SMEs? SMEs can benefit from interest deductibility to reduce their taxable base, provided they comply with applicable tax regulations.

11. How do international tax treaties influence LBOs? They allow for the reduction of withholding taxes on cross-border interest payments, which can improve the profitability of the transaction.

References

• Attention on intra-group loans and admissible rates
• OECD tax models and Swiss adjustments
• Swiss tax system: Overview
• Federal Tax Administration (withholding tax)