NIIT: The 3.8% Tax Most Landlords Forget About
The Net Investment Income Tax quietly adds 3.8% on top of your rental income, capital gains, and other investment earnings once you cross the income threshold. It's been around since 2013, but most landlords don't plan for it until they see it on their return. Here's how it works and what you can do about it.
The Bottom Line
A single landlord earning $280K with $50K in net rental income owes an extra $1,900 in NIIT alone. That's on top of ordinary income tax. But if you qualify as a Real Estate Professional (REPS), your rental income is exempt from NIIT entirely — potentially saving thousands every year.
In This Guide
- 1. What Is the Net Investment Income Tax?
- 2. Who Pays NIIT? Income Thresholds
- 3. What Counts as Net Investment Income
- 4. What Doesn't Count
- 5. How NIIT Is Calculated (with Example)
- 6. The REPS Exemption: How to Eliminate NIIT
- 7. Strategies to Reduce or Avoid NIIT
- 8. How SheltrIQ Helps You Plan for NIIT
1. What Is the Net Investment Income Tax?
The Net Investment Income Tax (NIIT) is a 3.8% surtax on investment income for individuals, estates, and trusts with income above certain thresholds. It was enacted as part of the Affordable Care Act (ACA) in 2010 and took effect on January 1, 2013.
The NIIT is codified under IRC Section 1411. Unlike ordinary income tax, it's a flat-rate surcharge applied on top of your regular tax liability. It's reported on Form 8960 and added to your total tax on Form 1040.
Why landlords miss it: NIIT doesn't show up in standard tax bracket discussions. Most landlords plan around the 22% or 24% bracket without realizing their effective rate on rental income is actually 25.8% or 27.8% once NIIT kicks in. It's a hidden 3.8% bump that catches people off guard.
The NIIT was designed to fund Medicare and ensure that investment income faces a comparable tax burden to employment income (which is subject to the 2.9% Medicare tax). For landlords with substantial rental portfolios, it can add up to thousands of dollars per year in additional tax.
2. Who Pays NIIT? Income Thresholds
NIIT applies when your modified adjusted gross income (MAGI) exceeds specific thresholds based on your filing status. The tax is triggered by your total income — not just your investment income.
| Filing Status | MAGI Threshold | NIIT Applies When |
|---|---|---|
| Single | $200,000 | MAGI exceeds $200K |
| Married Filing Jointly | $250,000 | Combined MAGI exceeds $250K |
| Married Filing Separately | $125,000 | Individual MAGI exceeds $125K |
| Head of Household | $200,000 | MAGI exceeds $200K |
| Qualifying Surviving Spouse | $250,000 | MAGI exceeds $250K |
Critical detail: These thresholds are NOT indexed for inflation. They've been frozen at the same dollar amounts since 2013. As incomes rise with inflation, more taxpayers get pulled into NIIT each year. A $200K income in 2013 is equivalent to roughly $260K in 2026 purchasing power — but the threshold hasn't moved.
3. What Counts as Net Investment Income
Net investment income (NII) includes most forms of passive and portfolio income. For landlords, rental income is typically the largest component. Here's what the IRS includes:
Rental income (net of expenses)
The big one for landlords. Includes all Schedule E rental income from properties where you don't materially participate.
Interest income
Bank interest, bond interest, mortgage note interest you receive as a lender.
Dividend income
Both ordinary and qualified dividends from stocks, mutual funds, and ETFs.
Capital gains
Short-term and long-term gains from selling stocks, bonds, rental properties, and other investments.
Royalties
Income from intellectual property, mineral rights, oil and gas leases.
Passive activity income
Income from businesses where you don't materially participate (limited partnerships, silent investments).
Annuity income (taxable portion)
The taxable portion of non-qualified annuity distributions.
Net means net: You can deduct properly allocable expenses from your investment income before calculating NIIT. For rental properties, this means all your Schedule E deductions (depreciation, mortgage interest, repairs, property taxes, insurance) reduce your NII. The 3.8% applies to the profit, not the gross rents.
4. What Doesn't Count
Not all income is subject to NIIT. Understanding what's excluded can help you structure your income to minimize the tax.
W-2 wages and salary
Already subject to Medicare tax
Self-employment income (material participation)
Subject to SE tax instead
Social Security benefits
Exempt from NIIT by statute
Tax-exempt interest
Municipal bond interest excluded
Retirement account distributions
401(k), IRA, pension distributions (in most cases)
Veterans' benefits
Exempt from NIIT
Active business income
If you materially participate in a non-rental business
Rental income with REPS status
Recharacterized as non-passive (see Section 6)
The key distinction: NIIT targets passive and portfolio income. If you actively work in a business and materially participate, that income is generally exempt. This is why the Real Estate Professional Status exemption (covered in Section 6) is so powerful — it reclassifies rental income from passive to active.
5. How NIIT Is Calculated (with Example)
NIIT is calculated as 3.8% of the lesser of two amounts: your net investment income, or the amount by which your MAGI exceeds the applicable threshold. This means you only pay NIIT on the smaller of these two numbers.
The Formula
Example: Marcus, Single Filer with Rental Properties
Income
NIIT Calculation
Why the lesser? Marcus's net investment income ($50K) is less than his excess over the threshold ($80K), so NIIT applies to $50K. If his NII were $100K instead, the excess ($80K) would be the lesser amount, and NIIT would be $3,040.
Stacking effect: Marcus pays 24% income tax + 3.8% NIIT = 27.8% effective federal rate on his rental income. At the state level, add another 5-13% depending on his state. This is why NIIT planning matters — it's not just 3.8%, it's 3.8% on top of everything else.
6. The REPS Exemption: How to Eliminate NIIT
Here's where it gets powerful. If you qualify as a Real Estate Professional (REPS) under IRC Section 469(c)(7), your rental income is recharacterized as non-passive income. Non-passive income is NOT net investment income — which means it's completely exempt from NIIT.
Example: Same Numbers, REPS Qualified
Without REPS
MAGI: $280,000
Net investment income: $50,000
NIIT owed: $1,900
With REPS
MAGI: $280,000
Net investment income: $0 (rental recharacterized)
NIIT owed: $0
To qualify as a Real Estate Professional, you must meet both of the following tests:
750 Hours Test
You must spend more than 750 hours during the year in real property trades or businesses in which you materially participate.
More Than Half Test
More than half of the personal services you perform during the year must be in real property trades or businesses. If you have a full-time W-2 job, this test is extremely difficult to meet.
Who benefits most: REPS is most valuable for households where one spouse manages rental properties full-time while the other works a W-2 job. The REPS spouse satisfies both tests, and the couple files jointly. See our REPS Qualification Guide for the full breakdown of requirements and hour-tracking strategies.
7. Strategies to Reduce or Avoid NIIT
Even if you can't qualify for REPS, there are several legitimate strategies to minimize your NIIT exposure.
Maximize rental deductions
Every dollar of deductible expense (depreciation, repairs, mortgage interest, property taxes) reduces your net investment income. Cost segregation studies can accelerate depreciation and significantly lower NII in the early years of ownership.
Increase retirement contributions
Maxing out your 401(k) ($23,500 in 2026) and IRA ($7,000) reduces your MAGI directly. A $23,500 401(k) contribution could reduce NIIT by up to $893. Employer plans, SEP IRAs, and solo 401(k)s offer even higher limits.
Time property sales across tax years
A large capital gain from selling a property can spike your MAGI and NII in a single year. If possible, close sales in a year when your other income is lower to stay below the threshold.
Consider installment sales
Selling a property via an installment sale (IRC Section 453) spreads the capital gain across multiple years, potentially keeping your MAGI below the threshold in each year instead of spiking it all at once.
Harvest investment losses
Capital losses offset capital gains dollar-for-dollar and reduce your net investment income. Strategically selling underperforming investments before year-end can lower your NIIT exposure.
Pursue REPS qualification
If you're close to the 750-hour and more-than-half tests, restructuring your time allocation toward real estate activities could eliminate NIIT entirely. The savings justify significant lifestyle adjustments for landlords with large portfolios.
Watch the MFS trap: Married couples sometimes consider filing separately to use the $200K threshold for the higher earner instead of the $250K joint threshold. But MFS has a $125K threshold — even lower. Filing separately almost never helps with NIIT and often costs more in lost credits and deductions elsewhere.
8. How SheltrIQ Helps You Plan for NIIT
NIIT planning requires knowing your numbers before year-end — not discovering a surprise $2,000+ tax bill in April. SheltrIQ builds NIIT awareness into the tools you already use.
Sale Calculator with NIIT
SheltrIQ's property sale calculator automatically includes NIIT in the tax projection. See the full federal tax picture — income tax, capital gains tax, depreciation recapture, AND NIIT — before you list a property.
What-If Scenario Modeling
Model how selling a property, changing your rental income, or adjusting retirement contributions affects your MAGI relative to the NIIT threshold. Test installment sale vs. lump-sum scenarios side by side.
REPS Hour Tracking
If you're pursuing REPS qualification to eliminate NIIT, SheltrIQ tracks your hours with contemporaneous, timestamped logs that satisfy IRS requirements. See your progress toward both the 750-hour and more-than-half tests.
Year-End Tax Projection
As you log income and expenses throughout the year, SheltrIQ projects your estimated NIIT liability in real-time. No more April surprises.
Don't Let NIIT Catch You Off Guard
SheltrIQ's sale calculator and what-if scenarios include NIIT automatically, so you see the full tax picture before making decisions. Free to get started.