0% Capital Gains Tax: Pay Nothing on Investment Gains in Low-Income Years
What Is It?
The federal tax code taxes long-term capital gains (assets held more than one year) and qualified dividends at preferential rates: 0%, 15%, or 20%, depending on your taxable income. If your taxable income falls below certain thresholds, you pay zero federal tax on long-term gains — regardless of how large those gains are. This creates a powerful planning opportunity in low-income years.
Do I Qualify?
- You have assets with long-term gains, meaning you held them more than one year
- Your taxable income for the year is low enough, or can be kept low enough, to leave room under the 0% threshold
- You understand that the gains themselves count toward the threshold
- You are looking at federal tax planning and know state tax may still apply
The 2024 Income Thresholds
| Filing Status | 0% rate up to | 15% rate up to | 20% rate above |
|---|---|---|---|
| Single | $47,025 | $518,900 | $518,900+ |
| Married Filing Jointly | $94,050 | $583,750 | $583,750+ |
| Head of Household | $63,000 | $551,350 | $551,350+ |
| Married Filing Separately | $47,025 | $291,850 | $291,850+ |
These thresholds are indexed to inflation annually. The comparison is made against your taxable income — that’s AGI minus your standard or itemized deduction.
Example: You are single with $40,000 of W-2 income and take the $14,600 standard deduction. Your taxable income is $25,400. You have room to realize $21,625 in long-term capital gains before hitting the 0% ceiling ($47,025 − $25,400 = $21,625). Federal tax on those gains: $0.
When This Window Opens
The 0% rate is most valuable in:
- Early retirement before Social Security or RMDs kick in
- Gap years — sabbaticals, career changes, time off between jobs
- Business sale years where ordinary income is low but capital assets are held
- College students with investment income from custodial accounts (subject to kiddie tax rules — see below)
- Partial-year employment — you worked 6 months and had lower income than usual
- Self-employed down years where business income dropped significantly
Tax Gain Harvesting: The Strategy
“Tax gain harvesting” is the deliberate realization of long-term capital gains in a year when your rate is 0%. The goal is to reset your cost basis — the price the IRS uses to calculate future gains — to today’s higher value.
How it works:
- Identify holdings with large unrealized long-term gains.
- Sell shares to realize gains up to the 0% ceiling.
- Immediately repurchase the same shares (there is no wash-sale rule for gains — only for losses).
- Your cost basis resets to the current price.
- Future gains above that new basis will be smaller.
This is the opposite of tax-loss harvesting (selling losers to offset gains) but serves the same ultimate goal: minimizing lifetime capital gains taxes.
Important Interactions
Net Investment Income Tax (NIIT): The 3.8% NIIT applies to investment income (including capital gains) for taxpayers above $200,000 (single) or $250,000 (MFJ) in modified AGI. The NIIT stacks on top of the capital gains rate — so even if your gains are at 0%, the NIIT doesn’t apply at these income levels. This is not a concern for taxpayers in the 0% bracket.
State taxes: Most states tax capital gains as ordinary income. The 0% federal rate does not eliminate state capital gains taxes. California, for example, taxes capital gains at up to 13.3%. Factor in state taxes when calculating the true benefit.
Kiddie tax: If you are claiming a child’s investment income on a joint return, or if the child is under 19 (or under 24 and a full-time student), the “kiddie tax” may apply — taxing the child’s unearned income above a threshold at the parent’s higher rate. The 0% rate strategy is limited in this context.
Alternative Minimum Tax (AMT): In rare cases, realizing large gains can trigger AMT exposure for higher-income filers. Run an AMT calculation before executing a large gain-harvesting transaction.
The Wash-Sale Rule Does Not Apply to Gains
This is a frequently misunderstood point. The wash-sale rule (which disallows loss deductions when you repurchase the same or substantially identical security within 30 days) only applies to losses. When you sell a position for a gain, you can immediately repurchase the same security the same day with no adverse tax consequence. Your holding period for the new shares restarts from the repurchase date.
What Most People Don’t Know
- Qualified dividends receive the same treatment. Qualified dividends (from U.S. corporations and qualifying foreign corporations, held for more than 60 days) are taxed at the same 0%/15%/20% rates as long-term gains. In a low-income year, your qualified dividends may also be completely tax-free.
- The gain itself counts toward the threshold. When you calculate the income ceiling, the capital gains themselves are stacked on top of your ordinary income. So if you have $40,000 of ordinary taxable income and sell stock with a $20,000 gain, your total taxable income is $60,000 — the $20,000 that pushed you above $47,025 is taxed at 15%, not 0%. Plan carefully.
- Roth conversions in the same year interact. A Roth conversion adds to your ordinary income, which pushes down the room available for 0% gains. In retirement planning, coordinate Roth conversions and gain harvesting in the same year carefully.
Frequently Asked Questions
I’m retired and my income comes mostly from Social Security. Can I use the 0% rate?
Potentially yes, but Social Security benefits are partially taxable (up to 85%) and count toward your AGI — which affects the room available under the 0% ceiling. Run a full projection with a tax calculator before selling investments.
Does this work for inherited investments?
Yes. Inherited assets receive a stepped-up basis, and if you sell them, any gains from the date of inheritance are long-term immediately (no one-year holding period required for inherited assets). Those gains qualify for the 0% rate if your income is below the threshold.
What about short-term capital gains?
Short-term gains (assets held one year or less) are taxed as ordinary income — there is no 0% rate for short-term gains. The preferential rates only apply to long-term gains and qualified dividends.
I’m in the 12% ordinary income bracket. Are all my capital gains at 0%?
If your total taxable income — including the gains — stays below the 0% threshold ($47,025 for single filers in 2024), yes. The 12% ordinary income bracket and the 0% capital gains bracket overlap in the same income range, which is exactly why this opportunity exists.