Retirees filing jointly can realize up to $96,700 in long-term gains at a 0% federal rate, but unused room vanishes permanently on December 31.
Selling appreciated shares and immediately repurchasing them resets the cost basis higher at zero tax cost, since wash-sale rules only apply to losses.
RMDs starting at 73 and a projected 3.3% Social Security COLA in 2027 will shrink this window, making pre-RMD years the prime harvest opportunity.
Picture a couple in their late 60s. He retired at 66, she at 64. Between them they collect roughly $54,000 a year in Social Security, pull $18,000 from a traditional IRA, and hold a $1.4 million portfolio split across a taxable brokerage account, IRAs, and a small Roth. Buried in that brokerage account sits about $52,000 in unrealized long-term gains on an S&P 500 index fund they bought a decade ago. Their CPA mentioned they might owe nothing if they sell before year-end. They are not sure they believe it.
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They should. This is one of the cleanest tax opportunities in the code, and it disappears at midnight on December 31.
Why This Scenario Is More Common Than You Think
Millions of retirees between ages 62 and 73 sit in the same window: retired, not yet taking required minimum distributions, drawing Social Security plus modest IRA withdrawals, with embedded gains in taxable accounts from the long bull market. Bogleheads forum threads on “0% capital gains harvesting” run to thousands of posts every autumn for exactly this reason. The strategy is legal and repeatable every calendar year until RMDs or higher spending push income above the threshold.
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Two figures do the heavy lifting. For 2026, the standard deduction for a married couple filing jointly is $32,200. The 0% long-term capital gains bracket for joint filers runs up to roughly $96,700 in taxable income. A couple can shelter about $128,900 of gross income, of which up to $96,700 can be long-term gains, and owe zero federal tax on those gains.
Run our couple through it. Roughly $46,000 of their Social Security is taxable once other income is layered in. Add the $18,000 IRA withdrawal and you land near $64,000 of ordinary income before the standard deduction. That leaves ample headroom under the $96,700 ceiling to realize the full $52,000 gain at a 0% federal rate.
Long-term gains stack on top of ordinary income. Any portion of the gain that falls below the 0% ceiling is taxed at 0%. Any dollar above it gets taxed at 15%. Miss by $5,000 and only that $5,000 is taxed, not the whole gain.
Why the December 31 Deadline Matters
Capital gains brackets reset every January 1. Unused room does not carry forward. A couple who realizes $0 in gains this year cannot “double up” next year at the 0% rate; they simply lose the 2026 allotment. Financial planners treat this as a use-it-or-lose-it annual event.
Two forces are tightening the window. The 2027 Social Security COLA is tracking toward 3.3%, which raises taxable ordinary income and shrinks the room available for gains. Once RMDs kick in at age 73, forced IRA withdrawals often push retirees out of the 0% bracket permanently. The years between retirement and RMDs are the harvest years, and they double as the cheapest Roth conversion years too (we sized up that same gap in a free guide here). There are not many of them.
Path one: harvest the gain, then immediately repurchase the same fund. The wash-sale rule applies only to losses, not gains, so there is no waiting period. The couple resets their cost basis $52,000 higher without owing a dollar of federal tax. If they later need to sell in a higher-income year, the taxable gain will be smaller.
Path two: do nothing and let the gains compound untouched. This is right only if the couple expects to hold the shares until death, at which point heirs receive a stepped-up basis and the gain is erased entirely. For most retirees who will eventually spend from the taxable account, holding is the inferior choice. Deferring a 0% tax bill to lock in a future 15% or 18.8% bill is a losing trade.
What to Do Before Year-End
Pull a tax projection now, not in December. You need a solid estimate of ordinary income, taxable Social Security, and any dividends before you know how much gain fits under the ceiling. Waiting until Christmas week leaves no room to adjust.
Watch state taxes separately. The 0% federal rate does not extend to most states. California, for instance, taxes long-term gains as ordinary income. If you live in a high-tax state, the harvest is not entirely free, and the math changes.
Coordinate with Roth conversions. Every dollar converted from a traditional IRA to a Roth counts as ordinary income and eats into your capital gains headroom. You generally cannot maximize both in the same year.
The common mistake: assuming a bigger gain means a bigger tax bill and avoiding the sale entirely. In the 0% bracket, the tax bill is zero regardless of whether you realize $5,000 or $50,000, as long as you stay under the ceiling. Leaving that room unused is the expensive choice.
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