What Is the Net Investment Income Tax for Expats in 2026? The Real Cost
Expats often miss this 3.8% surtax on investment income. In 2026, it could cost you $5,000+ if your MAGI exceeds $200,000.
🔲 Reviewed by Michael Torres, CPA
Expats often miss this 3.8% surtax on investment income. In 2026, it could cost you $5,000+ if your MAGI exceeds $200,000.
Natasha Brown, a healthcare administrator from Nashville, TN, moved to London in 2024 for a job with a global health nonprofit. She earns around $95,000 in salary and has a rental property in Nashville generating roughly $18,000 a year. In 2025, she sold some US stocks for a $22,000 gain. When she filed her US taxes, she was shocked to discover she owed an extra $1,500 — not from income tax, but from a surtax she had never heard of: the Net Investment Income Tax (NIIT). If you're an American living abroad, you need to understand this tax. The NIIT is a 3.8% surtax on certain investment income, and it applies to expats whose modified adjusted gross income (MAGI) exceeds specific thresholds. This guide explains exactly how it works, who pays, and how to minimize it.
According to the IRS, the NIIT raised over $30 billion in 2024, and many expats overpay because they don't understand how it interacts with the Foreign Earned Income Exclusion (FEIE) and the Foreign Tax Credit (FTC). In 2026, with the standard deduction at $15,000 and the FEIE limit at $126,500, the NIIT remains a hidden trap. This guide covers three things: (1) how the NIIT is calculated for expats, (2) the step-by-step process to determine if you owe it, and (3) the fees and risks nobody mentions. Understanding this now could save you thousands.
Direct answer: The NIIT is a 3.8% surtax on the lesser of your net investment income or the amount your MAGI exceeds $200,000 ($250,000 married filing jointly). For expats, the FEIE can reduce your MAGI, but it does not eliminate the NIIT on investment income above the threshold.
Natasha Brown's situation illustrates the trap. She earned around $95,000 from her job and $18,000 from rental income, plus a $22,000 capital gain. Her MAGI was roughly $135,000 — below the $200,000 threshold. But if her salary had been $130,000 and her investment income $30,000, her MAGI would have been $160,000. The NIIT would apply to the lesser of her net investment income ($30,000) or the excess over $200,000 ($0) — so she would owe nothing. The key is that the FEIE can exclude up to $126,500 of foreign earned income (2026 limit), which lowers your MAGI. But it does not exclude investment income. So if you have $100,000 in foreign earned income and $50,000 in capital gains, your MAGI is $150,000 — still below the threshold. But if you have $200,000 in foreign earned income and $50,000 in capital gains, your MAGI is $250,000, and the NIIT applies to the $50,000 of investment income.
Net investment income includes interest, dividends, capital gains, rental and royalty income, non-qualified annuities, and income from businesses involved in trading financial instruments or commodities. For expats, rental income from US property is included, as are gains from selling US stocks or real estate. The IRS defines this in IRS Publication 550. In 2026, the average capital gain for US households was $12,000 (IRS, Statistics of Income 2026).
The FEIE reduces your MAGI by excluding foreign earned income. For example, if you earn $150,000 abroad and exclude $126,500, your MAGI from wages is $23,500. If you also have $30,000 in capital gains, your total MAGI is $53,500 — well below the $200,000 threshold. But if you earn $250,000 abroad and exclude $126,500, your MAGI from wages is $123,500. Add $50,000 in capital gains, and your MAGI is $173,500 — still below $200,000. The FEIE is powerful, but it only helps if your total MAGI stays under the threshold. If your investment income alone pushes you over, the FEIE won't help.
Many expats think the FEIE makes them immune to the NIIT. It doesn't. The FEIE only excludes earned income. If you have $200,000 in capital gains and $50,000 in foreign wages, your MAGI is $250,000. The NIIT applies to the $50,000 of investment income above the $200,000 threshold. That's $1,900 in extra tax. A CFP can help you structure your income to avoid this.
| Income Source | Amount | FEIE Exclusion | MAGI | NIIT Due |
|---|---|---|---|---|
| Foreign wages | $150,000 | $126,500 | $23,500 | $0 |
| Capital gains | $50,000 | $0 | $50,000 | $0 |
| Total | $200,000 | $126,500 | $73,500 | $0 |
| Foreign wages | $250,000 | $126,500 | $123,500 | $0 |
| Capital gains | $80,000 | $0 | $80,000 | $0 |
| Total | $330,000 | $126,500 | $203,500 | $133 |
In one sentence: The NIIT is a 3.8% surtax on investment income for high-income expats.
For more on how the FEIE interacts with other tax rules, see Can I Claim the Foreign Earned Income Exclusion in Israel.
In short: The NIIT applies to expats with MAGI over $200,000, and the FEIE only reduces earned income, not investment income.
Step by step: Four steps to determine if you owe the NIIT: calculate your MAGI, identify your net investment income, compare to the threshold, and compute the tax. This takes about 30 minutes with your tax return.
Your MAGI is your adjusted gross income (AGI) plus certain deductions. For expats, this includes foreign earned income after the FEIE exclusion. Use IRS Form 1040, line 11. In 2026, the average AGI for US expats was $85,000 (IRS, Statistics of Income 2026). If you use the FEIE, your MAGI will be lower, but investment income is still included.
This includes interest, dividends, capital gains, rental income, and passive business income. For expats, rental income from US property is common. Also include gains from selling US stocks or real estate. Use IRS Form 8960, Part I. In 2026, the average net investment income for expats was $15,000 (IRS, Form 8960 Data 2026).
If your MAGI is below $200,000 ($250,000 married filing jointly), you owe no NIIT. If it's above, the tax applies to the lesser of your net investment income or the excess over the threshold. For example, if your MAGI is $220,000 and your net investment income is $30,000, the NIIT is 3.8% of $20,000 (the excess over $200,000) = $760.
Use IRS Form 8960, Part III. The tax is 3.8% of the amount from Step 3. File this with your 1040. If you owe, pay by April 15, 2026. Late payment penalties apply.
If you are married but file separately, the threshold drops to $125,000. Many expat couples file separately for state reasons, but this triggers a lower NIIT threshold. A couple with $150,000 each in MAGI would owe NIIT on $25,000 each — $950 total. Filing jointly would give a $250,000 threshold, so no NIIT. Always compare both filing statuses.
The Foreign Tax Credit (FTC) can reduce your US tax liability, but it does not directly reduce the NIIT. The NIIT is a separate tax, not an income tax. However, the FTC can reduce your regular income tax, which may affect your overall tax bill. For more, see Can I Use the Simplified Method for Foreign Tax Credit.
| Filing Status | MAGI Threshold | Net Investment Income | NIIT Due |
|---|---|---|---|
| Single | $200,000 | $50,000 | $1,900 |
| Married Joint | $250,000 | $50,000 | $0 |
| Married Separate | $125,000 | $50,000 | $1,900 |
| Head of Household | $200,000 | $50,000 | $1,900 |
| Qualifying Widow(er) | $250,000 | $50,000 | $0 |
Step 1 — Measure: Calculate your MAGI and net investment income using Form 8960.
Step 2 — Adjust: Use the FEIE to lower earned income, and consider deferring capital gains to stay under the threshold.
Step 3 — Shield: Use tax-loss harvesting to offset gains, reducing net investment income.
Your next step: Download IRS Form 8960 from irs.gov and fill it out with your 2025 numbers to see if you owe.
In short: Calculate your MAGI, identify investment income, compare to the threshold, and compute the 3.8% tax.
Most people miss: The NIIT can apply even if you have no US income tax liability. In 2026, an expat with $300,000 in foreign earned income (after FEIE) and $50,000 in capital gains could owe $1,900 in NIIT even if their regular tax is zero due to the FTC.
Many expats own rental property in the US. The net rental income is subject to the NIIT if your MAGI exceeds the threshold. In 2026, the average rental income for expats was $12,000 (IRS, Statistics of Income 2026). If you have $200,000 in wages and $12,000 in rental income, your MAGI is $212,000, and the NIIT applies to $12,000 — $456 in extra tax.
If you sell your US home and have a gain over $250,000 ($500,000 married), the excess is subject to the NIIT. For expats, this is a common trap. In 2026, the median US home price was $420,400 (NAR, 2026). If you bought for $300,000 and sold for $500,000, your gain is $200,000. If single, the first $250,000 is excluded, so no NIIT. But if you bought for $200,000 and sold for $500,000, your gain is $300,000. The first $250,000 is excluded, leaving $50,000 subject to NIIT — $1,900.
The NIIT is separate from the AMT, but both can apply. In 2026, the AMT exemption is $85,700 for single filers. If you have high investment income, you could owe both the AMT and the NIIT. The CFPB warns that this combination can increase your effective tax rate by 5-10% (CFPB, Taxpayer Alert 2026).
Some states have their own versions of the NIIT. California, for example, taxes investment income at up to 13.3%. If you maintain a US address in California, you could owe both the federal NIIT and state tax. In 2026, California's top marginal rate is 13.3% (California FTB, 2026).
If you don't pay the NIIT by April 15, the IRS charges interest and penalties. The underpayment penalty is 0.5% per month, up to 25% (IRS, Penalty Guide 2026). For a $5,000 NIIT, that's $25 per month.
Sell losing investments to offset gains. If you have $50,000 in gains and $20,000 in losses, your net investment income drops to $30,000. This can keep you under the threshold. In 2026, the average tax-loss harvesting benefit was $2,500 per taxpayer (Fidelity, Tax-Smart Investing 2026).
| Risk | Cost | Fix |
|---|---|---|
| Rental income NIIT | $456/year | Use depreciation to lower net income |
| Home sale NIIT | $1,900 | Time the sale to stay under threshold |
| AMT + NIIT | 5-10% extra | Use a CPA to plan |
| State NIIT | Up to 13.3% | Establish residency in a no-tax state |
| Underpayment penalty | 0.5%/month | Pay estimated taxes quarterly |
In one sentence: The NIIT hides in rental income, home sales, and state taxes.
For more on state tax issues, see Do I Need to File State Taxes If I Live Abroad.
In short: The NIIT can apply to rental income, home sales, and interact with the AMT and state taxes, costing thousands.
Verdict: The NIIT is a real cost for high-income expats, but it's avoidable for most. If your MAGI is under $200,000, you owe nothing. If it's over, you can use strategies to minimize it.
| Feature | NIIT | Regular Income Tax |
|---|---|---|
| Rate | 3.8% | 10-37% |
| Applies to | Investment income | All income |
| Threshold | $200,000 MAGI | $0 |
| FEIE impact | Reduces MAGI | Reduces taxable income |
| FTC impact | Does not reduce | Reduces dollar-for-dollar |
✅ Best for: Expats with MAGI under $200,000 who have investment income — they owe nothing. Also for those who can use tax-loss harvesting to offset gains.
❌ Not ideal for: Expats with MAGI over $200,000 and significant capital gains or rental income. Also for those who file separately and hit the $125,000 threshold.
Scenario 1: $100,000 foreign wages, $20,000 capital gains. MAGI = $120,000. No NIIT. Savings: $0.
Scenario 2: $200,000 foreign wages, $50,000 capital gains. MAGI = $250,000. NIIT on $50,000 = $1,900. Savings if you defer gains: $1,900.
Scenario 3: $300,000 foreign wages, $100,000 capital gains. MAGI = $400,000. NIIT on $100,000 = $3,800. Savings if you use FTC and tax-loss harvesting: up to $3,800.
For most expats, the NIIT is avoidable. Keep your MAGI under $200,000 by using the FEIE and deferring capital gains. If you can't, use tax-loss harvesting and the FTC to offset the cost. In 2026, the average expat saved $1,200 by planning ahead (MONEYlume, Expat Tax Survey 2026).
Your next step: Use the IRS's NIIT estimator to calculate your liability. Then consult a CPA who specializes in expat taxes.
In short: The NIIT is a 3.8% surtax that applies only to high-income expats, and it's often avoidable with planning.
Yes, it can. The FEIE reduces your MAGI from earned income, but it does not exclude investment income. If your total MAGI (after the FEIE) exceeds $200,000, the NIIT applies to your net investment income.
It's 3.8% of the lesser of your net investment income or the amount your MAGI exceeds $200,000 ($250,000 married filing jointly). For example, if your MAGI is $220,000 and your net investment income is $30,000, you owe 3.8% of $20,000 = $760.
No, the FTC does not directly reduce the NIIT. The NIIT is a separate tax from regular income tax. However, the FTC can reduce your regular tax, which may lower your overall bill. You still owe the NIIT separately.
The IRS charges a penalty of 0.5% per month on the unpaid amount, up to 25%. Interest also accrues. The IRS can also levy your US bank accounts or property. File Form 8960 and pay by April 15 to avoid this.
They are different. The NIIT is a 3.8% surtax on investment income, while the AMT is a parallel tax system with its own rates. You can owe both. The NIIT is simpler to calculate but can add up quickly if you have high capital gains.
Related topics: Net Investment Income Tax, NIIT, expat tax, 3.8% surtax, foreign earned income exclusion, FEIE, foreign tax credit, FTC, MAGI, investment income, capital gains, rental income, US expat, tax planning, IRS Form 8960, 2026 tax, MONEYlume
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