At a glance
- What it is
- Planning around the 3.8% net investment income tax (NIIT) under IRC §1411, so it applies only where it must.
- What it saves
- 3.8% federal tax on rental income, K-1 income, and gains that qualify as active business income.
- Best fit
- Owners with income over $250,000 (married) or $200,000 (single) who own rentals, other businesses, or investments.
- Main catch
- Exemptions depend on facts like hours worked, which you have to be able to prove.
- Thresholds
- $250,000 married filing jointly, $200,000 single. They aren’t adjusted for inflation.
Key takeaways
- The net investment income tax adds 3.8% on investment income for married couples above $250,000, or singles above $200,000.
- Owners often pay it on income that can be exempt, like rent from their own company or K-1 income from businesses they work in.
- In the illustrative example, documenting participation and reporting the rent correctly cuts the couple’s 3.8% tax from $11,400 to $1,900.
- The catch: exemptions depend on facts like hours worked, and participation claimed without contemporaneous records often fails in an audit.
The numbers
Picture a married couple with $800,000 of income. They own the building their S corporation operates from and rent it to the company for $150,000 a year. One spouse also owns part of a second company and already works there more than 500 hours a year, but it was reported as passive, putting $100,000 of K-1 income in the 3.8% tax. They also have $50,000 of dividends and interest.
For illustration purposes. Tax law may change, which may change these calculations slightly.
Personal tax: net investment income tax (federal)
| Before | After | |
|---|---|---|
| Rent from their own S corp | $150,000 | $0 |
| K-1 income from the second company | $100,000 | $0 |
| Dividends and interest | $50,000 | $50,000 |
| Net investment income | $300,000 | $50,000 |
| Net investment income tax (3.8%) | $11,400 | $1,900 |
Same income, about $9,500 less federal tax every year. The rent qualifies because it comes from a business they materially participate in, and the K-1 income qualifies once the hours are documented. Their regular income tax doesn’t change. Oklahoma has no equivalent tax.
Could this strategy work for your business?
In a free tax analysis, your tax strategist checks whether it fits and what it could save, using your real numbers.
How it works
- Know what’s taxed. Interest, dividends, capital gains, rents, royalties, and income from businesses where you don’t materially participate. The tax applies to the smaller of that income or your income above the threshold.
- Know what’s not. Wages, income from businesses you materially participate in, distributions from retirement plans, and tax-exempt interest.
- Rent to your own business correctly. Rent from property leased to a business you materially participate in is generally not net investment income, when it’s set up and reported correctly.
- Prove participation. Material participation usually means 500+ hours a year, or meeting one of the other IRS tests. Keep a calendar or log.
- Plan the big years. Retirement plan contributions, installment sales, charitable trusts, and timing can keep income and gains below the line or out of the tax.
Who it fits
- Owners who lease buildings or equipment to their own companies.
- Owners with K-1s from more than one business.
- Real estate investors who may qualify as real estate professionals.
- Owners planning to sell a business they work in. Gain on an active business can be largely exempt.
When it doesn’t help
- Pure investment portfolios: dividends, interest, and stock gains are taxed regardless of hours.
- Businesses you truly don’t work in.
The rules
- Material participation tests. There are seven tests. The most common is 500+ hours in the year. Spouses’ hours count together.
- Grouping elections. Related businesses can sometimes be grouped as one activity so your hours count across them. Groupings are hard to change later.
- Real estate professionals. Rental income generally escapes the tax only if you qualify as a real estate professional and your rental activity rises to a trade or business with material participation.
- Selling a business interest. Gain on selling an S corp or partnership interest is exempt to the extent it would be active business gain if the business sold its assets.
- Trusts. Trusts hit the 3.8% tax at much lower income, so trust income needs its own planning.
Risks and costs to weigh
- Records. Participation claimed without contemporaneous records often fails in an audit.
- Passive losses. Making an activity nonpassive can stop it from absorbing passive losses from other activities. We model both sides.
- Reasonable compensation. Moving S corp profit into wages removes it from this tax but adds payroll tax. The salary still has to be reasonable.
How we handle it for clients
With a Cannon & Brown tax plan, we review every source of income for the 3.8% tax: rents, K-1s, trusts, and planned sales. We set up participation logs, grouping elections, and leases the right way, and make sure your returns report it correctly. Because our technology keeps your numbers current all year, we can see the tax coming and plan around it before year end. Your tax strategist reviews every recommendation.
Illustrative example. The couple and figures on this page are hypothetical, used to explain how the strategy works. They are not a client and not a promise of results. The example assumes married filing jointly, $800,000 of modified adjusted gross income, material participation in the S corporation that rents the building, documented material participation in the second company, and $50,000 of dividends and interest. This page is educational and is not tax or legal advice for your situation; tax rules and limits change.
Common questions about the net investment income tax
Is rent from my own business subject to the 3.8% tax?
Rent from property leased to a business you materially participate in is generally not net investment income, when it’s set up and reported correctly.
Does the 3.8% tax apply to my S corp K-1 income?
Not if you materially participate in the business, which usually means 500+ hours a year or meeting one of the other IRS tests. Income from businesses where you don’t materially participate is subject to it.
Does Oklahoma have a net investment income tax?
No. Oklahoma has no equivalent tax, so this is a federal-only issue.
Can I avoid the 3.8% tax on dividends and stock gains?
Not by logging hours: dividends, interest, and stock gains are taxed regardless of hours. For big years, retirement plan contributions, installment sales, charitable trusts, and timing are the planning tools.
Brooks leads Cannon & Brown Tax Advisors, a forward-thinking tax firm serving business owners in Oklahoma and beyond. He builds year-round tax strategies that help business owners keep more of what they earn and reach their goals. More about Brooks
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