Net Investment Income Tax (NIIT) for Real Estate Investors

You've already paid income tax on your rental profits. Then came the 3.8% NIIT — a surtax layered on top, with no inflation adjustment and no phase-out above the threshold. For a high-income investor with $80K of passive rental income, that's an extra $3,040 a year. Here's who pays it, what triggers it, and how strategies like REPS and 1031 exchanges eliminate or defer it.

What is the NIIT?

The Net Investment Income Tax was enacted under the Affordable Care Act and took effect in 2013. Under IRC § 1411, it imposes a 3.8% surtax on the lesser of: (a) your net investment income, or (b) the amount by which your modified adjusted gross income (MAGI) exceeds the applicable threshold.¹

These thresholds are statutory floors, not inflation-adjusted. Congress set them in 2010 and has not changed them since. Every year they erode in real terms: a couple earning $250,001 in 2026 with $30,000 of passive rental income pays $1,140 of NIIT; the same couple in 2013 dollars needed significantly more purchasing power to cross that line.

What counts as net investment income for real estate investors?

Net investment income under § 1411(c) includes three broad categories. For real estate investors, the most relevant are:¹

• Passive rental income — Schedule E rental profits from properties in which you do not materially participate as a real estate professional
• Capital gains from property sales — long-term capital gain, § 1250 unrecaptured depreciation gain, § 1245 recapture, and any other gain recognized on the disposition of a passive rental property
• Interest, dividends, and annuities — less common for pure real estate investors, but included in the NII base

What is not net investment income: wages, self-employment income, active business income, Social Security benefits, and — critically — rental income or gains from activities in which you are not passive (e.g., because you qualify as a real estate professional).

How the math works — a worked example

Suppose you're married filing jointly with $240,000 of W-2 income plus $50,000 of passive rental profit and $60,000 of capital gain from selling a rental property. Your MAGI is $350,000.

That $3,800 is on top of the 20% LTCG tax, the 25% § 1250 unrecaptured rate, and any state income tax. For investors with large rental portfolios or a significant sale in a given year, the NIIT adds meaningful cost.

REPS: the most powerful NIIT shield for rental income

If you qualify as a real estate professional under IRC § 469(c)(7) — more than 750 hours in real property trades or businesses, and more than half your personal services in those activities — and you materially participate in your rental activities, your rentals are reclassified as non-passive. Non-passive income is not net investment income.²

The IRS formalized this in Treas. Reg. § 1.1411-4(g)(7): a safe harbor applies when a real estate professional materially participates in rental real estate for more than 500 hours during the year, or for more than 500 hours in any 5 of the 10 prior tax years.³ Under the safe harbor, rental income is treated as derived in the ordinary course of a trade or business and is excluded from NII.

The grouping election matters here. Under Reg. § 1.469-4, you can elect to treat all rental activities as a single activity for material participation purposes. Without the election, you must separately meet a material participation test for each individual property — easy for a hands-on landlord with two properties, potentially impossible for someone with 10 properties and a property manager on each.

The STR loophole and NIIT

Short-term rentals with an average stay of 7 days or fewer are not "rental activities" for § 469 purposes — meaning the passive-per-se rule doesn't apply.⁴ If you materially participate in the STR (typically 500+ hours for the 500-hour test, or "substantially all" participation), it's treated as an active business.

For NIIT purposes, the same logic applies: if the STR activity is non-passive because of material participation, the income and any gain on sale are not NII. The STR loophole is available even to investors who don't qualify for full REPS — it's a property-by-property analysis, not a portfolio-wide election.

Without material participation, STR income is passive income and is subject to NIIT like any other rental.

Capital gains on rental sales — the four-layer stack

When you sell a rental property at a gain, the tax hit comes in layers. For a passive investor above the NIIT threshold, all four apply:

NIIT stacks on top of every layer — including the § 1245 recapture that is already taxed at ordinary income rates. For a high-cost-seg investor selling a passive property, ordinary recapture income generates both a 37% federal income tax hit and a 3.8% NIIT hit simultaneously.

REPS eliminates the NIIT layer entirely. The capital gains and recapture rates still apply, but the 3.8% surtax disappears.

Five strategies to reduce NIIT exposure

1. Qualify for REPS (or the STR loophole)

The most direct path. REPS makes all rental income and gains non-passive, removing them from the NII base entirely. For a full-time real estate investor or a spouse who manages the portfolio, REPS is achievable — see our REPS guide and REPS calculator for the requirements and tax value.

2. Execute a 1031 exchange on sale

A properly structured 1031 exchange defers gain recognition entirely. No gain recognized → no NII → no NIIT. The exchange doesn't eliminate the underlying NIIT exposure; it defers it (along with the capital gains) until a future taxable disposition. Ultimately, dying with like-kind property (step-up at death eliminates all deferred gain) can turn "deferred" into "never." See the 1031 calculator for the deferral math.

3. Installment sale to spread NII across years

If your MAGI is $260,000 in a sale year (barely above the $250,000 MFJ threshold), a large capital gain pushes a lot of NII into the 3.8% zone. Spreading the gain over 5–9 years via an installment sale keeps more of each year's NII in the threshold shadow — meaning less of the total gain is subject to NIIT. Caveat: § 453(i) requires § 1245 recapture income to be recognized in full in the year of sale, so cost-seg recapture is always in year 1 regardless of installment structure.

4. Invest deferred capital gains in a Qualified Opportunity Zone

The OZ 2.0 program (OBBBA, 2025) allows you to roll any capital gain — including gain from a rental sale — into a Qualified Opportunity Fund within 180 days. The underlying gain is deferred, and any appreciation in the QOF after a 10-year hold is excluded from tax entirely — meaning it never enters the NII base. See our QOZ guide for the 2026 rules including the new rural step-up.

5. Let PALs absorb passive income

Suspended passive activity loss carryforwards are deductible against NII in the year of full disposition, reducing the net gain subject to NIIT. A portfolio with large PAL carryforwards and a modest property basis may see the NIIT base effectively zeroed out by the carryforward release. This is one reason a specialist advisor models PAL balances as part of exit planning — releasing losses at exactly the right time has real dollar value.

What OBBBA and recent legislation changed

The One Big Beautiful Bill Act (July 2025) did not modify the NIIT rate or thresholds. The Social Security Fairness Act (January 2025) repealed WEP and GPO but has no interaction with NIIT. OBBBA's changes most relevant to this guide: 100% bonus depreciation restored permanently (affects § 1245 recapture exposure on future cost seg sales) and the QOZ 2.0 rolling deferral structure (see strategy 4 above).

The planning conversation

NIIT planning for real estate investors is a second-order problem: it only matters once you've already built a portfolio generating meaningful passive income or facing a significant sale. But the strategies that eliminate NIIT — REPS, 1031s, QOZ — interact with each other in ways that generalist advisors routinely miss. A specialist models the four-layer tax stack across the full disposition sequence, not just the year of sale.

Sources

1. IRS Topic No. 559 — Net Investment Income Tax. IRC § 1411 imposes 3.8% surtax on lesser of NII or MAGI in excess of threshold. 2026 thresholds: $200,000 single, $250,000 MFJ, $125,000 MFS. Thresholds are not indexed for inflation. Definition of NII includes passive rental income, capital gains from passive activity dispositions, interest, dividends, and annuities. Verified May 2026.
2. IRC § 469(c)(7) — Real Estate Professional Status. 750-hour threshold; more than half of personal services in real property trades or businesses. Rental activities of a qualifying REP who materially participates are non-passive — and therefore excluded from net investment income under § 1411. Verified May 2026.
3. Treas. Reg. § 1.1411-4(g)(7) — Safe Harbor for Real Estate Professionals. Rental income of a qualifying real estate professional who materially participates for more than 500 hours in the current year, or 500 hours in any 5 of the prior 10 tax years, is treated as derived in the ordinary course of a trade or business and is not net investment income. Verified May 2026.
4. Treas. Reg. § 1.469-1T(e)(3)(ii)(A) — Average Period of Customer Use. Activities with average customer use of 7 days or fewer are not "rental activities" for § 469 purposes. Material participation in such activities results in non-passive treatment — and therefore exclusion from NIIT. Verified May 2026.
5. IRS Publication 550 — Investment Income and Expenses. Net investment income definition, Form 8960 computation instructions, and interaction with capital gains. Verified May 2026.

NIIT thresholds ($200K/$250K/$125K for individuals) are statutory and not inflation-indexed. The $16,000 2026 estate/trust AGI threshold is annually indexed. The NIIT rate (3.8%) and scope were not modified by OBBBA (2025), SECURE 2.0 (2022), or the Social Security Fairness Act (2025). Values verified May 2026. Consult a qualified tax advisor for your specific situation.