One sale, two separate tax systems
When you sell a home in Switzerland, you are not dealing with one tax event. The sale triggers a Swiss cantonal Grundstückgewinnsteuer — the property gains tax — and a separate US income tax calculation on your worldwide capital gain. Each country has its own rulebook, its own currency, and its own relief provisions. The good news: most American sellers can plan for both.
- Swiss tax
- Cantonal Grundstückgewinnsteuer on the gain; seller pays; rate depends on canton and holding period
- US tax
- Capital gain on worldwide income, unless the Section 121 principal-residence exclusion applies
- Principal-residence relief
- Swiss long-hold discounts and rollover for a replacement home; US up to $250,000 single / $500,000 married filing jointly
- Currency
- Swiss gain in CHF; US gain recomputed in USD; mortgage repayment can create a separate currency result
The Swiss side: cantonal Grundstückgewinnsteuer on the gain
Switzerland has no federal capital-gains tax on private property. Instead, the canton — sometimes with the commune — taxes the gain: sale price minus purchase price, value-increasing improvements, and selling costs. The rate depends on both the canton and how long you held the home, with shorter holds generally paying more and longer holds paying less. The tax is paid by the seller. If you are still near the purchase side, our guide to buying a home in Switzerland as a US citizen explains the entry costs that later create part of your tax basis.
- Zurich adds a 50% surcharge if you sell within one year and 25% if you sell within two years; after five years it starts giving long-hold discounts of 5% per year up to a 50% reduction.
- Aargau starts around 40% in year one and falls to roughly 5% by year 25.
- Geneva charges a flat 50% within the first two years, falls to 10% for 10–25 years, and can drop to 2% after 25 years.
- Ticino starts around 31% in year one and falls to about 4% after 30 years.
- Most cantons also allow a rollover — Ersatzbeschaffung — if the proceeds go into a replacement primary residence within a reasonable period.
The US side: Section 121 can exclude much of the gain
A US citizen is taxed on worldwide income, so a foreign home sale is a US taxable event even though the home is in Switzerland. The good part is that the Section 121 principal-residence exclusion applies to homes outside the US. If in the five years ending on the sale you owned the home for at least two years and used it as your main home for at least two years — 24 months, not necessarily continuous — you can exclude up to $250,000 of gain if single or $500,000 if married filing jointly. Location abroad does not disqualify you. If the gain is at or below the exclusion and you meet the tests, you generally do not need to report the sale. One exception: the exclusion is denied to covered expatriates.
The US dollar gain can be very different from the Swiss franc gain. Convert the purchase price and capital improvements at the rate on the date you paid them, and convert the sale proceeds at the rate on the date you sold. If the franc rose against the dollar while you owned the home, your US gain could be larger than the Swiss gain; if the dollar strengthened, it could be smaller or even disappear.
The foreign tax credit: Swiss property gains tax on your US return
The Swiss Grundstückgewinnsteuer is a creditable foreign tax because it is an income-type tax on realized gain — unlike the Swiss wealth tax, which is generally not creditable against US income tax. You claim the credit on Form 1116 in the passive basket. There is one built-in mismatch to expect: if Section 121 excludes the gain on the US side, there is no US tax on that excluded portion, so the Swiss tax attributable to the excluded gain produces no foreign tax credit — there is no double tax to relieve. The credit only helps on the non-excluded, taxable portion of the gain.
The currency wrinkle when you repay the CHF mortgage
Selling often coincides with repaying the Swiss mortgage. Under Rev. Rul. 90-79, the mortgage repayment is treated as a separate transaction from the home sale. If the dollar strengthened against the franc between the time you borrowed and the time you repaid, the repayment can trigger a taxable ordinary currency gain — while a currency loss is generally non-deductible. We unpack this in Congress drops phantom currency mortgage relief for Americans abroad.
Educational information only
These rules are general. Your actual Swiss rate depends on your canton, holding period and improvements; your US outcome depends on your filing status, use of the home, and whether any gain exceeds the exclusion. Before you sign a sale contract, have a cross-border tax professional model both sides.
Plan the sale with both systems on the table
The trap is rarely one bad rule — it is the combination of two systems that were never designed to align. You can sell a Swiss home, claim the Section 121 exclusion, use the foreign tax credit on any taxable remainder, and still have an unexpected currency gain from the mortgage repayment. As specialists for Americans in Switzerland, we look at both systems under one roof so you can walk into the sale with a clear number and a defensible filing.