Long-term capital gains are taxed at 0% up to $48,350 single / $96,700 MFJ of taxable income on 2025 returns. How gain harvesting works and who can actually use it.
Yes, there is a legal 0% tax rate on investment gains, and it isn't a loophole — it's the bottom bracket of the long-term capital gains schedule. On 2025 returns, long-term gains are taxed at 0% until your taxable income exceeds $48,350 (single) or $96,700 (married filing jointly). Land your income under those lines in the right year and you can sell appreciated stock and pay the IRS nothing on the gain.
The bracket hides in plain sight because high earners never see it — but almost every investing career includes low-income windows where it swings open: a sabbatical, early retirement, grad school, a startup year, the gap before Social Security starts. It's one of the timing plays in our roundup of the best tax-planning moves high-income W-2 employees can make precisely because "high income" is rarely permanent. Here's how the math works, what gain harvesting is, and the traps at the edges.
The thresholds apply to taxable income — income after the standard deduction (or itemized deductions), not your gross income. That single detail makes the bracket far roomier than it looks. For a married couple in 2025, the standard deduction is $31,500; stack it on the $96,700 threshold and the couple can have roughly $128,000 of total income — wages, gains, everything — before a dollar of long-term gain leaves the 0% zone. Also important: the gains themselves count toward taxable income and stack on top of your ordinary income, filling the bracket from wherever your other income leaves off. Only the portion of gain that spills above the threshold gets taxed, and at 15% — crossing the line by $1,000 costs $150, not retroactive tax on everything.
A married couple both take 2025 off — a sabbatical year with $20,000 of part-time and interest income. They hold index funds bought years ago: $150,000 of value with $90,000 of unrealized long-term gain.
Federal tax on the $90,000 gain: $0. They realized six figures of proceeds and a ninety-thousand-dollar gain, legally tax-free, because they timed the sale into a low-income year. The same sale in a $300,000-income working year would have cost roughly $13,500 at 15% — plus possibly more at the margins. Timing was worth five figures.
Here's the move that makes the bracket valuable even if you don't need the cash: sell the appreciated shares and immediately buy them back. Your portfolio is unchanged, the gain is realized at 0%, and your cost basis resets to the new, higher price — permanently shrinking the gain you'll owe tax on when you eventually sell for real in a higher-income year.
And unlike loss harvesting, there is no wash-sale rule for gains. The wash-sale rule only disallows losses when you repurchase within 30 days — the IRS has no objection to you realizing a gain and rebuying the same second, because you're voluntarily recognizing income. It's the mirror image of the loss-side discipline we cover in tax-loss harvesting and the wash-sale rules: harvest losses in high-income years, harvest gains in low-income ones. One caution — don't harvest losses and gains in the same low-income year without thinking; losses offset the gains first, wasting them exactly when the gains would have been free anyway.
Harvest losses when your rate is high. Harvest gains when your rate is zero.
In these same windows, gain harvesting competes with Roth conversions for the empty bracket space — both want your low-rate years, and every dollar of conversion income pushes gains toward the threshold. Charitably inclined? Appreciated stock plus a low-income year also interacts with the giving strategies in our donor-advised fund and bunching guide — sometimes harvesting the gain at 0% and giving cash beats donating the shares. Sequencing them is genuinely a planning exercise.
Mechanics matter here. First, confirm the holding period: only long-term gains (held over one year) get the 0% rate — short-term gains are ordinary income at full rates, so check acquisition dates lot by lot and sell your oldest, highest-gain long-term lots first. Second, do the math in December, not April: you need a solid estimate of the year's total income before you can size the sale to fill, but not overflow, the bracket. Third, use specific-lot identification with your broker rather than the default first-in-first-out, so you control exactly which gains you realize. A harvest sized to the dollar in late December is the difference between a clean 0% and an accidental spill into 15%.
Two edges to watch. First, your state probably doesn't have a 0% bracket — most states tax capital gains as ordinary income, so a "tax-free" harvest can still generate a state bill (Californians, take note; Texans and Floridians, carry on). Second, the 3.8% net investment income tax applies above $200,000 single / $250,000 MFJ of modified AGI — those thresholds aren't indexed, and NIIT math runs on MAGI, not taxable income. It's rarely a problem in a genuinely low-income year, but a big enough harvest can create its own MAGI problem. Realized gains can also affect income-tested items like ACA premium credits — check the whole picture before executing a six-figure sale.
On 2025 returns, the 0% bracket runs to $48,350 single / $96,700 MFJ of taxable income — and with the standard deduction stacked on top, a low-income year can absorb a genuinely large long-term gain at a 0% federal rate. Map your low-income windows, harvest gains into them (and rebuy freely — no wash-sale rule applies), and mind state tax, NIIT, and competing Roth conversions. Taxagon's tax planning team sizes 0% bracket harvests down to the dollar for clients in transition years — if you'd rather not navigate it alone, reach out.
This article is general information, not tax advice for your specific situation. Tax law changes; figures are for the years stated.
Talk it through with a licensed US tax professional — we'll tell you honestly whether it applies to your situation.
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