Elena's rental turned a genuine profit this year, and the extra income itself triggered a second, separate tax most landlords have never heard of: the 3.8% Net Investment Income Tax. Her $192,000 salary alone sits under the $200,000 single-filer threshold — but add her rental's $19,000 of taxable Schedule E income, and her combined MAGI of $211,000 clears it by $11,000, adding $418 on top of the ordinary tax she already expected.
The Passive Loss Conversation Nobody Has About a Good Year
Most of what gets written about MAGI and rental property is about losses — whether you can deduct them, and how the $25,000 allowance phases out as your income climbs. Elena had read that article. What she hadn't seen covered anywhere is the mirror-image question: what happens to MAGI when the rental finally makes money instead of losing it. The answer isn't a bigger deduction. It's a second tax on the income itself, and it only shows up once your combined income — salary plus rental profit — crosses a threshold that has nothing to do with your tax bracket.
Elena's Numbers
Elena is single. Her Schedule E nets out to $19,000 this year after rent, operating expenses, and depreciation — a genuinely good year, with no vacancy and no major repairs.
Step 1 — Ordinary tax on the rental income. Her taxable income (salary minus the $16,100 single standard deduction) is $175,900, which puts her in the 24% marginal bracket. That's the rate the next dollar of rental income is taxed at:
$19,000 × 24% = $4,560
Step 2 — Check the NIIT threshold. The Net Investment Income Tax applies once Modified Adjusted Gross Income exceeds $200,000 for a single filer. Elena's salary alone ($192,000) doesn't cross it. Add the rental income and it does:
$192,000 + $19,000 = $211,000 combined MAGI — $11,000 over the $200,000 threshold.
Step 3 — NIIT applies to the smaller of the two numbers. The tax applies to whichever is less: her net investment income ($19,000) or the amount her MAGI exceeds the threshold by ($11,000). Here that's $11,000:
$11,000 × 3.8% = $418
Total federal tax on the rental this year: $4,560 + $418 = $4,978 — not the $4,560 Elena was expecting when she ran the ordinary-bracket math herself.
| Amount | |
|---|---|
| Taxable Schedule E income | $19,000 |
| Ordinary tax (24% bracket) | $4,560 |
| Combined MAGI | $211,000 |
| NIIT threshold (single) | $200,000 |
| Amount subject to NIIT | $11,000 |
| NIIT (3.8%) | $418 |
| Total federal tax on the rental | $4,978 |
Why This Is Easy to Miss
NIIT gets framed almost entirely as a high-earner problem — something that shows up on investment portfolios, not a single rental that nets under $20,000. But the threshold is a MAGI test, not an income-source test. It doesn't care that the $19,000 came from a modest duplex instead of a stock portfolio; it only cares that her total crossed $200,000. A landlord whose W-2 income already sits close to the threshold can be pushed over it by a rental that simply had a good year — no refinance, no sale, no change in the property itself.
It also runs the opposite direction of the passive-loss conversation. A loss-generating rental can actually reduce MAGI enough to stay under the threshold or qualify for the $25,000 allowance. A profit-generating one adds to MAGI and can push a landlord who was previously under $200,000 over it for the first time — the better the year, the more likely NIIT applies.
What Changes the Math
Married filing jointly raises the threshold to $250,000, not double Elena's — so a couple with similar combined income faces this later, not never. A loss year removes NIIT from this calculation entirely; the tax only applies to positive net investment income. And state income tax is separate — NIIT is a federal-only tax, so a landlord in a no-income-tax state like Texas or Florida pays only the federal $4,978; one in a state with its own income tax owes that on top.
Check Your Own Combined MAGI
If your W-2 or self-employment income is within $20,000–$30,000 of the $200,000 (single) or $250,000 (married filing jointly) threshold, a profitable year on a rental can tip you into NIIT territory even if the rental itself only clears a few thousand dollars after expenses. Run your own numbers through the Landlord Tax Estimator — it factors in your actual MAGI, marginal rate, and NIIT exposure together, rather than estimating the rental in isolation.
Frequently Asked Questions
What counts as MAGI for the NIIT threshold?
For most landlords without foreign income or certain deductions, MAGI for NIIT purposes is the same as your regular Adjusted Gross Income — your wages, self-employment income, interest, dividends, and net rental income, added together before the standard or itemized deduction. It's your combined income across every source, not the rental in isolation.
Does NIIT apply if my rental loses money this year?
No. NIIT only applies to positive net investment income. A loss year produces $0 of net investment income from the rental, so there's nothing for the 3.8% to apply to — though the loss itself is subject to the separate passive-loss rules, which phase out as MAGI climbs.
Is the $200,000 threshold the same as the NIIT amount I owe tax on?
No — those are two different numbers in the calculation, and mixing them up is the most common mistake. The $200,000 is just the line that determines whether NIIT applies at all. Once you're over it, the tax applies to the smaller of your net investment income or the amount your MAGI exceeds the threshold by — not automatically the whole $19,000.
Does this apply to short-term rentals the same way?
If a short-term rental is treated as a trade or business where you materially participate (the STR loophole many hosts use to escape passive-loss limits), its income may be treated differently for NIIT purposes than a standard passive rental — this is a case-specific question worth confirming with a CPA rather than assuming either way.
Can I do anything in-year to reduce NIIT exposure?
Timing deductible rental expenses (a repair versus waiting until next year), maximizing retirement account contributions that reduce MAGI, and — for a landlord close to the line — simply knowing the threshold exists before year-end are the realistic levers. There's no NIIT-specific deduction; it's a function of staying under the combined-income threshold in the first place.