How Is Portfolio Income Taxed? Rates, NIIT, and Accounts

Portfolio income is taxed in one of two ways at the federal level: either at your ordinary income tax rates (10% to 37%) or at the preferential long-term capital gains rates of 0%, 15%, or 20%. Which set of rates applies depends on the type of income and, for investment gains, how long you held the asset. High earners pay an extra 3.8% surtax on top of either rate, and where you hold the investment matters too, since retirement accounts can defer or eliminate the tax entirely.

The Two Rate Buckets

Federal tax law splits investment income into two categories. The first bucket covers income taxed at ordinary rates, the same brackets that apply to your salary. Interest from bank accounts and corporate bonds, short-term capital gains, and non-qualified dividends all land here. The second bucket covers income eligible for preferential rates: long-term capital gains and qualified dividends.

The holding period is what sorts most investment gains between these two buckets. Sell an asset you owned for one year or less, and the profit is a short-term capital gain taxed at ordinary rates.¹ Hold it longer than one year, and you qualify for the preferential rates.² That one-year line is worth planning around, because the rate difference can be substantial.

Income Taxed at Ordinary Rates

Most interest income is taxed at your regular marginal rate. Interest from savings accounts, money market accounts, certificates of deposit, and corporate bonds all count as ordinary income, added to your wages and other earnings when calculating your tax bill.³ For 2026, ordinary income tax rates range from 10% to 37%, with the top rate reached at $640,600 for single filers and $768,700 for married couples filing jointly.⁴

U.S. Treasury bond interest has one useful quirk: it’s taxable at the federal level but exempt from state and local income taxes.³ Corporate bond interest doesn’t get that break.

Non-qualified dividends also fall into the ordinary-rate bucket. A dividend is non-qualified when the stock wasn’t held long enough to meet the holding period test, or when it comes from certain organizations that don’t pay corporate-level tax. Short-term capital gains round out the category. Buy stock in January, sell it in October at a profit, and that gain stacks on top of your other income at whatever bracket it falls into.

Municipal Bond Interest

The biggest exception to the interest-is-ordinary rule is municipal bonds. Interest from bonds issued by state and local governments is generally excluded from federal gross income.⁵ That’s what makes municipal bonds appealing to investors in higher brackets, since the tax savings can more than offset the lower stated yields. Not every municipal bond qualifies for the exemption, though. Certain private activity bonds may be subject to the alternative minimum tax, and taxable municipal bonds exist when the bond’s purpose doesn’t meet federal public-use requirements.

Original Issue Discount

If you hold a zero-coupon bond or any bond purchased at a discount to its face value, you may owe tax on “phantom income” each year even though no cash arrives until maturity. The IRS requires you to include a portion of the original issue discount in your income annually as interest, reported on Form 1099-OID.³ This catches some investors off guard.

Long-Term Capital Gains and Qualified Dividends

The preferential rate structure is why most long-term investors pay less tax on their gains than they would on the same amount of salary. Long-term capital gains and qualified dividends are taxed at 0%, 15%, or 20%, depending on your total taxable income.⁶

For 2026, the income thresholds for each rate are:⁴

0% rate: taxable income up to $49,450 for single filers, $98,900 for married filing jointly, and $66,200 for heads of household.
15% rate: taxable income above the 0% ceiling but not exceeding $545,500 single, $613,700 joint, and $579,600 for heads of household.
20% rate: taxable income above the 15% ceiling.

The 0% bracket is genuinely powerful for lower-income investors. A married couple with $90,000 in taxable income who sells stock at a long-term gain pays no federal tax on that gain. It’s one of the most underused tax advantages available to retirees living primarily on investment income.

What Makes a Dividend Qualified

Not all dividends get the preferential rate. To qualify, you need to hold the underlying stock for at least 61 days within the 121-day window that begins 60 days before the ex-dividend date.⁷ The dividend also has to come from a U.S. corporation or a qualifying foreign corporation covered by a tax treaty. Miss either condition and the dividend is taxed at your ordinary rate.

Collectibles and Depreciation Recapture

Two categories of long-term gains face higher preferential rates than the standard 0/15/20% structure. Gains on collectibles like artwork, coins, antiques, and precious metals are capped at 28%.¹ And when you sell real property on which you previously claimed depreciation deductions, the portion of gain attributable to that depreciation (unrecaptured Section 1250 gain) is capped at 25%.⁶ These are maximum rates. If your income is low enough to fall in a lower bracket, you pay the lower rate.

How Capital Losses Work

When you sell an investment at a loss, that loss first offsets gains of the same type: short-term losses reduce short-term gains, long-term losses reduce long-term gains. If total losses exceed total gains for the year, you can deduct up to $3,000 of the excess against your other income ($1,500 if married filing separately).¹ Anything left over carries forward to future years indefinitely, so a big losing year isn’t wasted from a tax perspective.

Mutual Fund Distributions

Mutual funds create a tax situation that surprises many investors: you can owe tax on gains even when you didn’t sell anything. When a fund manager sells holdings inside the fund at a profit, those capital gains get distributed to shareholders and are taxable to you, whether you took the cash or reinvested it. Reinvested distributions are treated identically to cash distributions.

The character of the distribution flows through to you. If the fund held an asset for more than a year before selling, the distribution is a long-term capital gain taxed at preferential rates. Short-term fund gains pass through as ordinary income. Your fund will send you a Form 1099-DIV breaking down which portion is which. One mistake to avoid: reinvested distributions increase your cost basis, and if you forget to account for them when you eventually sell your fund shares, you’ll pay tax on the same gains twice.

The 3.8% Net Investment Income Tax

High earners face an extra 3.8% surtax on portfolio income called the Net Investment Income Tax. It applies on top of whatever rate you already owe, whether that’s the preferential capital gains rate or your ordinary bracket. The NIIT was enacted under Section 1411 and covers interest, dividends, capital gains, rental income, and royalties.⁸

The tax kicks in when your modified adjusted gross income exceeds:

$200,000 for single filers and heads of household
$250,000 for married filing jointly
$125,000 for married filing separately

You owe 3.8% on whichever amount is smaller: your net investment income or the amount by which your modified AGI exceeds the threshold.⁸ These thresholds are fixed by statute and do not adjust for inflation, which means more taxpayers cross them each year as incomes rise.

The practical impact is real. A high-income taxpayer in the 20% long-term capital gains bracket actually pays a combined federal rate of 23.8% on those gains. Someone in the top ordinary bracket of 37% pays an effective 40.8% federal rate on interest income. You report the NIIT on Form 8960.⁹

Estates and trusts are also subject to the NIIT, and they hit the threshold much faster. For 2026, the tax applies to undistributed net investment income once a trust or estate’s adjusted gross income exceeds just $16,000.

The Wash Sale Rule

Investors who sell a losing position for the tax benefit and then immediately buy it back run into the wash sale rule. Sell stock or securities at a loss and acquire a substantially identical investment within 30 days before or after the sale, and the IRS disallows the loss deduction entirely.¹⁰ That creates a 61-day window (30 days before the sale, the sale date, and 30 days after) during which repurchasing the same security blocks your loss.

The disallowed loss isn’t permanently gone. It gets added to the cost basis of the replacement shares, so you eventually capture the benefit when you sell those replacement shares. But it does prevent you from harvesting a loss this year while holding the same economic position. The rule also applies to purchasing options or contracts on the same security during the window. If you’re doing year-end tax-loss harvesting, the simplest fix is to wait a full 31 days before repurchasing, or buy into a similar but not substantially identical fund in the interim.

How Retirement Accounts Change the Picture

Everything above applies to investments held in a regular taxable brokerage account. Holding the same investments inside a tax-advantaged retirement account changes the answer completely, and this is where a lot of portfolio income tax planning actually happens.

Traditional IRAs and 401(k)s

Investment income earned inside a traditional IRA or 401(k) isn’t taxed as it grows. You owe nothing on dividends, interest, or capital gains while the money stays in the account. The trade-off: withdrawals are taxed as ordinary income at whatever your marginal rate is when you take the distribution, regardless of whether the underlying gains would have been taxed at preferential rates in a taxable account. A long-term capital gain that would have been taxed at 15% in a brokerage account gets taxed at your ordinary rate when it leaves a traditional IRA.

Roth IRAs

Roth IRAs flip the equation. Contributions go in with after-tax dollars, but qualified distributions, including all the investment growth, come out completely tax-free.¹¹ To qualify, you generally need to be at least 59½ and have held the account for at least five years. For investors who expect to be in a high tax bracket during retirement, the Roth structure can eliminate portfolio income taxes on those assets entirely.

Because of these differences, the conventional wisdom is to hold tax-inefficient investments (like bonds generating ordinary interest) inside tax-advantaged accounts, while keeping tax-efficient investments (like index funds generating mostly long-term gains) in taxable accounts. This approach, called asset location, can meaningfully reduce your lifetime tax bill without changing your investment strategy at all.

Paying the Tax During the Year

Unlike wages, portfolio income typically has no tax withheld at the source. If you earn significant investment income during the year, you’re expected to make quarterly estimated tax payments rather than waiting until you file. The IRS generally requires estimated payments if you expect to owe $1,000 or more in tax after subtracting withholding and credits.¹²

You can avoid underpayment penalties by meeting one of two safe harbors: paying at least 90% of your current-year tax liability through estimated payments, or paying 100% of your prior-year tax liability (110% if your prior-year AGI exceeded $150,000). The prior-year method is simpler and protects you even if a big gain unexpectedly spikes your current-year income. Payments use Form 1040-ES on a quarterly schedule.¹³

This trips up retirees and investors who shift from wage income to portfolio income more than anyone else. If you’re used to your employer handling withholding and suddenly have a year with a large capital gain distribution from a mutual fund, the penalty for skipping estimated payments can sting.

State Taxes on Portfolio Income

Federal taxes are only part of the picture. Most states with an income tax also tax portfolio income, and the majority do not offer a preferential rate for long-term capital gains. In those states, your investment gains are taxed at the same rate as your wages. A handful of states impose no income tax at all, so portfolio income escapes state taxation entirely for residents there. State treatment of municipal bond interest also varies: most states exempt interest from their own bonds but tax interest from bonds issued by other states.

1
Internal Revenue Service. Topic No. 409, Capital Gains and Losses
2
Office of the Law Revision Counsel. 26 USC 1222 – Other Terms Relating to Capital Gains and Losses
3
Internal Revenue Service. Topic No. 403, Interest Received
4
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
5
Office of the Law Revision Counsel. 26 USC 103 – Interest on State and Local Bonds
6
Office of the Law Revision Counsel. 26 USC 1 – Tax Imposed
7
Legal Information Institute. 26 USC 1(h)(11) – Dividends Taxed as Net Capital Gain
8
Office of the Law Revision Counsel. 26 USC 1411 – Imposition of Tax
9
Internal Revenue Service. Instructions for Form 8960
10
Office of the Law Revision Counsel. 26 USC 1091 – Loss From Wash Sales of Stock or Securities
11
Internal Revenue Service. Roth IRAs
12
Internal Revenue Service. Estimated Taxes
13
Internal Revenue Service. About Form 1040-ES, Estimated Tax for Individuals