Here's the short version: On August 31, 2026, the U.S. Court of Appeals for the Federal Circuit reversed earlier taxpayer wins in Estate of Bruyea and Christensen. The court held that foreign tax credits cannot offset the 3.8% Net Investment Income Tax, even under the Canada-US and France-US income tax treaties. For Americans living in Switzerland, that means Swiss tax paid on dividends, interest, capital gains, or real estate rentals does not reduce your NIIT bill. The result can be genuine double taxation on the same investment income.
What the August 31, 2026 Federal Circuit decision actually held
The Federal Circuit consolidated two independently litigated refund claims — Estate of Bruyea v. United States and Christensen v. United States — and reversed lower court decisions that had allowed foreign tax credits against NIIT. The court's logic rested on the structure of the Internal Revenue Code: NIIT lives in Chapter 2A, while the foreign tax credit rules in Sections 27 and 901 are explicitly part of Chapter 1. The treaties at issue incorporate U.S.-law limitations on the credit, and the court read those limitations as confining the credit to Chapter 1 taxes. The practical effect is that treaty benefits do not override this limitation.
A quick NIIT refresher
The 3.8% NIIT applies to net investment income — dividends, interest, capital gains, rental income, and certain annuities — when your modified adjusted gross income exceeds the statutory threshold for your filing status.
Key facts about NIIT and foreign tax credits
- NIIT is imposed under IRC Section 1411 on investment income above the applicable MAGI threshold.
- Foreign tax credits under Sections 27 and 901 generally prevent double taxation on foreign-source income, but Treasury regulations bar them against NIIT.
- Switzerland taxes the same dividends, interest, capital gains, and real estate under its own system, often through final withholding or income tax, so the tax is real and not hypothetical.
- The Federal Circuit's decision does not change what income is taxable; it only removes one avenue of cross-crediting relief.
Why this matters in Switzerland: the double-taxation gap
Swiss tax on investment income is common: dividends paid by Swiss companies are generally subject to Swiss withholding tax, and gains on Swiss real estate are often taxed in the canton where the property sits. A US person resident in Switzerland must report that income to the IRS, and the foreign tax credit would normally be the tool to avoid paying twice. With NIIT now clearly outside credit reach, the 3.8% is added on top of Swiss tax even when your Swiss effective rate is already substantial. It's important to understand the type of investment income involved: Swiss dividends face different treatment than certain capital gains, and Swiss withholding tax mechanics matter for your US return.
Why not just rely on the US-Swiss tax treaty?
The Federal Circuit decision involved the Canada-US and France-US treaties, not the US-Swiss income tax treaty. However, the reasoning is broader: many income tax treaties incorporate the same U.S.-law limitations on the foreign tax credit, and the IRS has long taken the position that treaty relief does not override the Chapter 2A limitation. A separate development on the US-Switzerland treaty may affect dividend rates and limitation-on-benefits rules, but it does not create a special NIIT credit. This means Americans in Switzerland should not assume the treaty fixes the NIIT gap — it likely does not. Always verify your exact treaty position before making a transaction decision.
No need to panic, but do adjust your assumptions
A ruling like this is not a penalty trap. It narrows a credit but does not change reporting rules, extend statutes, or create new penalties. If you missed foreign tax credits in past years, there are ordinary correction paths; the priority now is forward-looking planning.
What you can still do: planning around the NIIT gap
You cannot magically erase NIIT, but you can reduce its impact. Because NIIT applies only to net investment income above the MAGI threshold, everything that lowers MAGI or recharacterizes income can help. That does not mean hiding income; it means timing the sale of appreciated Swiss real estate, harvesting capital losses in the same year, maximizing deductible contributions where available, and checking whether your activity rises to the level of a trade or business. If you hold funds or ETFs in Swiss accounts, the PFIC problem can magnify the cost, so you need to solve the investment-structure question and the NIIT question together — Swiss mutual funds and ETFs can already create punitive US tax treatment before NIIT is even considered.
Another lever is housekeeping: tracking basis correctly matters, because inflated gain creates both Swiss and US tax. Accurate records let you claim the right foreign tax credit on the Chapter 1 portion of your tax return and keep NIIT exposure as low as the code allows. This is exactly the kind of cross-border coordination that benefits from advice before the transaction closes.
Bottom line
The August 31, 2026 Federal Circuit decision removes a common assumption: that foreign tax credits can offset NIIT under an income tax treaty. For Americans in Switzerland, that means Swiss investment tax and the 3.8% NIIT can stack. The solution is not to avoid investing, but to structure investments, timing, and tax positions deliberately. Educational information only — individual planning depends on your full situation.