Are the brokerage commission and other sales costs always deductible as investment costs when calculating property gains tax?

Deductibility of sales costs

No, brokerage commissions and sales costs are not always fully deductible. The tax offices only recognize costs that were normal local and necessary for sales success. In most cantons, the limit for brokerage commissions is 2% to 3% of the selling price. If the costs exceed this framework (e.g. 5% commission), the excess portion is often rejected as a “hobby” or concealed use of profit and does not reduce the taxable profit.

brokerage commission: The crux of local practice

The brokerage commission is legally considered a profit cost. It reduces net profit, as it represents a necessary expense to make the sale possible in the first place. However, in 2026, the cantons have very different ideas of what is “appropriate.”

Cantonal limits in check

• Zurich Canton: The tax office generally recognizes 2% as usual. Up to 3% are accepted for very cheap properties (under 500,000 CHF), and often even less than 2% for luxury properties. Higher deductions must be proven by extreme difficulties in selling.
• Canton of Bern: The authorities are often a bit more generous here; commissions of up to 3% or even 4% can go through with appropriate proof.
• Canton of Lucerne: Considered very restrictive. Here, only 1% to 2% are often recognized as deductible for built-up plots of land.

What other sales costs are deductible?

In addition to the brokerage fee, there are a number of other items that you should include in your property gains tax return.

The list of accepted deductions

• Notary and land registry fees: Insofar as these were contractually borne by the seller (often divided in half).
• Advertising and marketing costs: Costs for professional photos, drone photography, virtual tours and listings on real estate portals, provided that these are not already included in the brokerage fee.
• Early repayment penalty: If you have to cancel your mortgage early as a result of the sale, this “penalty interest” is deductible from property gains tax in most cantons (e.g. ZH, BE).
• Debt note costs: The deletion or adjustment of debt letters in the land register.

When the tax office refuses to deduct

There are clear scenarios in which the assertion of sales costs fails. In 2026, transparency through digital payment flows is so high that “tricks” are immediately noticeable.

Common reasons for rejection

• Private Brokerage: If you sell the property yourself, you cannot count a fictitious hourly wage as a “brokerage commission.” Only payments made to independent third parties are deductible.
• Related people: Commissions paid to family members or own companies are critically examined. Here, it must be proven that the same amount would also have been paid to an external real estate agent (third-party comparison).
• Lack of causality: Costs that did not lead directly to the conclusion (e.g. general consulting costs without sales) are deleted.

Documentation: No deduction without receipt

The burden of proof lies with the taxpayer. Anyone who fills out the real estate gains tax return must be able to prove every detail.

The perfect “tax file”

Be sure to have the following documents ready:

The written brokerage contract including fee agreement.

The broker's detailed final statement.

Payment proofs (bank documents) that prove that the money actually flowed.

Evidence of value-adding investments that increase the investment value.

Strategy with heyloft.ch: optimization before selling

In a market environment characterized by complex tax rules in 2026, technology helps you calculate the profitability of your sale in advance.

Why AI analysis helps with sales costs

heyloft.ch helps you not to give away francs:

• Deduction check: Our algorithms compare your planned sales costs with cantonal practices in Switzerland (e.g. Geneva or Zurich) and warn you if your brokerage commission is above the limit.
• Net return calculator: We calculate the expected revenue for you after deduction of property gains tax so that you can securely finance your next project.
• Dossier power: A professional sales application file helps to achieve the best possible price, which reduces the relative burden of brokerage costs.

Conclusion: System beats luck through factual knowledge

Are the brokerage commission and other sales costs always deductible? No They are only there if they are verifiable, necessary and local practice. Anyone who blindly agrees on excessive commissions pays twice in the end: once to the real estate agent and once to the tax office because the deduction is reduced.

In summary, before signing the contract, contact the real estate agent to find out about the cantonal practices of your location. Anyone who plans ahead and uses heyloft.ch's data power to professionally conduct their tenant due diligence (or seller audit) optimizes their tax burden legally and efficiently. With the right strategy, your perfect match — financially maximized and tax-clean — is within reach.

glossary

• Extraction costs: All expenses that are directly related to the realisation of the real estate profit (e.g. commissions, advertisements).
• Local practice: The standard used by tax offices to assess whether a fee is appropriate in regional comparison.
• Early repayment penalty: Compensation payment to the bank in the event of early termination of a fixed-rate mortgage, often deductible as investment costs.
• Tenant due diligence (seller check): The systematic review of all deductible costs before filing the tax return in order to avoid objections from the tax office.