What the Net Investment Income Tax Is

The Net Investment Income Tax (NIIT) is a 3.8% federal tax on certain investment earnings. It applies only to higher-income individuals and married couples filing jointly, and only on the portion of their investment income that exceeds the income thresholds set by law. You do not pay it on wages from a job — only on money your investments generate.

The tax was created as part of the Affordable Care Act and took effect in 2013. It is separate from the capital gains tax or income tax you may already owe on investment earnings. This means you could owe both the regular capital gains tax and the NIIT on the same investment profit.

The IRS collects NIIT through your annual tax return. You do not make separate quarterly payments for it the way you might for self-employment income, though if your investment income is very high, estimated tax payments may be required.

Key Takeaways

  • The Net Investment Income Tax is 3.8% and applies only if your income exceeds $200,000 (single filers) or $250,000 (married filing jointly).
  • It taxes investment income only — capital gains, dividends, interest, rental income, and profits from selling property — not wages or salary.
  • You owe NIIT only on the amount of investment income above the threshold, not on your entire income.
  • The tax is reported on Form 8960 and included with your annual tax return; you do not file it separately.
  • Certain types of income, such as tax-exempt bond interest and gains on the sale of your primary home (up to the exclusion limit), are not subject to NIIT.

Income Thresholds That Trigger the Tax

The NIIT applies only if your modified adjusted gross income (MAGI) exceeds a specific threshold. For the 2024 tax year, those thresholds are $200,000 for single filers, $250,000 for married couples filing jointly, and $125,000 for married individuals filing separately. These thresholds do not adjust for inflation each year — they remain fixed at these amounts.

MAGI for NIIT purposes is usually your adjusted gross income (AGI) from your tax return, with a few adjustments added back. For most people, it is the same as the AGI they report on Form 1040. If you are close to the threshold, a tax professional can help you calculate whether you will owe NIIT.

If your income is below the threshold, you owe no NIIT, regardless of how much investment income you earned. If your income is above the threshold, you owe NIIT only on the amount of net investment income that exceeds the threshold — not on your entire income.

What Types of Income Count as Investment Income

Investment income for NIIT purposes includes capital gains (profit from selling stocks, bonds, real estate, or other assets), dividends, interest earned on savings accounts or bonds, rental income from property you own, and income from partnerships or S corporations that are considered passive investments. It also includes gains from selling collectibles and certain commodity transactions.

Wages, salary, self-employment income from an active business, and Social Security benefits do not count as investment income for NIIT purposes. Neither does income from a may have access to retirement plan distribution, though the earnings within that plan may have been subject to NIIT before distribution.

Some types of investment income are excluded entirely from NIIT. Tax-exempt bond interest is never subject to NIIT. Gains on the sale of your primary residence are excluded up to $250,000 for single filers and $500,000 for married couples filing jointly, as long as you meet the ownership and use tests.

How the Tax Is Calculated and Reported

You calculate NIIT using Form 8960, which you attach to your Form 1040 when you file your annual return. The form walks you through determining your net investment income, comparing it to your MAGI, and calculating the 3.8% tax on the amount above the threshold.

The calculation is straightforward once you have the numbers: if your MAGI is $220,000 and you are a single filer, the threshold is $200,000, so $20,000 of your income is subject to NIIT. The tax on that $20,000 is $760 (3.8% of $20,000). You add this amount to your regular income tax liability.

If you have a complex tax situation — multiple rental properties, significant investment income, or business ownership — a tax professional can help ensure Form 8960 is completed correctly. Errors on this form can trigger an audit or result in underpayment penalties.

Who Is Most Likely to Owe This Tax

High-income earners are most likely to owe NIIT: retirees living on investment income, people who sell a business or significant assets, real estate investors with rental income, and individuals with substantial stock portfolios that generate dividends. A person earning $150,000 in wages plus $80,000 in investment income would owe NIIT on the investment portion if their total MAGI exceeds the threshold.

Business owners who sell their company or a significant stake may suddenly owe NIIT in the year of sale if the proceeds push their income above the threshold. Similarly, someone who inherits a rental property and collects rent may cross the threshold for the first time and owe NIIT on that rental income going forward.

Conversely, a person earning $300,000 in wages alone but no investment income owes no NIIT, even though their total income far exceeds the threshold. The tax applies only to investment earnings, not to wages.

Strategies to Reduce or Avoid NIIT

If you are close to the NIIT threshold, timing the sale of an asset or deferring investment income to a later year may keep you below the threshold for that tax year. Realizing a capital loss in the same year as a capital gain can offset the gain and reduce your net investment income. Donating appreciated securities to charity instead of selling them can eliminate the capital gain entirely.

Tax-exempt bonds generate interest that is never subject to NIIT, so shifting a portion of your portfolio to municipal bonds may reduce your NIIT liability. Holding investments in a may have access to retirement account (such as a 401(k) or IRA) means the earnings inside the account are not subject to NIIT, though distributions from the account may affect your MAGI.

These strategies have trade-offs and may not be right for your situation. A tax professional or financial advisor can review your specific circumstances and discuss which approaches make sense for you.

Frequently Asked Questions

Do I owe NIIT if I have investment losses?

No. If your net investment income is negative (your losses exceed your gains), you owe no NIIT for that year. You can carry forward unused losses to offset investment income in future years, which may reduce or eliminate NIIT in those years.

Is NIIT the same as capital gains tax?

No, they are separate taxes. Capital gains tax is the federal income tax on profit from selling an asset. NIIT is an additional 3.8% tax that applies only to high-income earners. You may owe both on the same capital gain.

Do I owe NIIT on money in my 401(k) or IRA?

No. Earnings inside a retirement account are not subject to NIIT while the money remains in the account. When you withdraw money from the account, the withdrawal itself does not trigger NIIT, but it may increase your MAGI, which could cause other investment income to become subject to NIIT.

What if I am self-employed — do I owe NIIT on business income?

Generally, no. Self-employment income from an active business is not subject to NIIT. However, if you sell the business or a significant stake in it, the gain from that sale is investment income and may be subject to NIIT if your total income exceeds the threshold.

Can I pay NIIT through estimated quarterly payments?

If your NIIT liability is large enough that you would owe underpayment penalties, you may need to make estimated quarterly tax payments that include NIIT. Most people report NIIT on their annual return and pay it when they file. A tax professional can advise whether quarterly payments are necessary in your situation.