NIIT on Rental Property: The 3.8% Tax Explained

The net investment income tax is a flat 3.8% surtax that most landlords meet for the first time on a return they thought was finished. For passive rental owners, it applies to net rental income, and, more painfully, to the gain when a rental sells, once modified adjusted gross income crosses $200,000 single or head of household, $250,000 married filing jointly, or $125,000 married filing separately.

Those thresholds come straight from IRC 1411 and are the quiet story here: they were set in 2013 and have never been adjusted for inflation. Every year, ordinary wage growth pushes more two-income households and moderately successful landlords into a tax originally aimed much higher up the income scale.

The mechanics are simple, the exceptions are not. The tax is 3.8% of the lesser of your net investment income or your MAGI above the threshold. The planning lives in the exceptions: real estate professional status with material participation can pull rental income out of NIIT entirely, and the treatment of a sale depends on the property’s history. This guide works through each with real 2026 numbers.

NIIT equals 3.8% of the lesser of two amounts: your net investment income for the year, or the amount by which your MAGI exceeds your threshold ($200,000 single or head of household, $250,000 MFJ, $125,000 MFS, per IRC 1411 and IRS Topic 559). It is computed on Form 8960 and stacks on top of regular income tax and capital gains tax.

Net investment income includes interest, dividends, capital gains, royalties, income from passive activities, and, for most owners, net rental income after deductions like depreciation, mortgage interest, repairs, and management fees. It does not include wages, self-employment income, distributions from qualified retirement plans and IRAs, or municipal bond interest.

The lesser-of structure means the tax can be limited from either side. A retiree with $150,000 of MAGI owes nothing regardless of rental profits. A W-2 earner at $600,000 with only $10,000 of net rental income owes NIIT on just the $10,000.

For most landlords, yes. Rental activity is passive by statutory default under IRC 469, and passive income is net investment income. Owning through an LLC changes nothing; a single-member LLC’s rental income lands on Schedule E and into Form 8960 exactly as if you owned the property directly.

The principal exit is real estate professional status combined with material participation. A taxpayer who qualifies for REPS under IRC 469(c)(7), more than 750 hours and more than half of working time in real property trades, and who materially participates in the rentals, holds the rental income outside the passive category, and outside NIIT. The regulations under 1411 add a safe harbor: a real estate professional with more than 500 hours in rental activities is treated as deriving that income in the ordinary course of a trade or business.

Two more narrow exits exist. Self-rental income, renting a building to your own operating business where you materially participate, is recharacterized as non-passive and excluded from NIIT under the regulations. And short-term rental operators whose average stays are seven days or less are outside the rental-activity definition; with material participation, that income is non-passive and generally outside NIIT as well, though it may raise self-employment tax questions when substantial services are involved.

A warning on the machinery: hitting these tests depends on hour logs, grouping elections under Reg. 1.469-9(g), and facts that survive audit. The REPS rules are covered in depth on our real estate professional status pages linked below; do not claim the exclusion from a summary paragraph.

The year you sell a rental is usually the year NIIT costs the most. The entire taxable gain, including the unrecaptured Section 1250 depreciation portion taxed at up to 25%, is net investment income for a passive owner, and the gain itself inflates MAGI past the threshold. A couple with $180,000 of wages who would never otherwise owe NIIT can owe it in the sale year alone.

For 2026, that stacks to a meaningful all-in rate: up to 20% federal long-term capital gains, up to 25% on the recapture slice, plus 3.8% NIIT, plus state tax. On a $300,000 gain with MAGI well over the threshold, NIIT alone is $11,400.

The exits mirror the income rules. Gain from a rental that was a non-passive trade or business for a qualifying real estate professional is generally outside NIIT. A 1031 exchange defers the gain, and with it the NIIT, entirely. And installment sales spread the gain across years, which can keep MAGI below the threshold in each year rather than blowing through it once.

Start with the base: NIIT applies to net rental income, so every legitimate deduction, depreciation, cost segregation where appropriate, repairs, interest, professional fees, reduces the 3.8% base along with regular tax. Suspended passive losses from prior years also offset passive rental income in the NIIT computation when released.

Next, MAGI management. Maxing pre-tax retirement contributions, HSA contributions, and charitable planning lowers MAGI toward the threshold. For 2026, an MFJ couple at $260,000 MAGI is only $10,000 over; a deductible retirement contribution can eliminate their NIIT exposure entirely.

The structural lever is participation status: REPS with material participation for a spouse who genuinely works in real estate, the self-rental recharacterization for business owners who own their building, and the short-term rental route for operators who actually run hospitality-grade operations. Each is fact-specific and documentation-heavy, which is exactly why they survive when done properly and fail when improvised.