Tax Gain Harvesting at the 0% Rate: A 2026 Case Study for a $118K Couple

A married couple filing jointly in 2026 can have up to $98,900 of taxable income and still pay a 0% federal rate on long-term capital gains, according to the IRS inflation adjustments in Revenue Procedure 2025-32. Most households in that range never use that space. Tax gain harvesting means selling appreciated investments on purpose and buying them right back, so a gain that would be taxed later gets taxed at zero now. This case study walks through one fictional but realistic couple’s 2026 numbers, shows exactly how much gain they can harvest before December 31, and lists the traps that can turn a free basis step-up into a surprise bill.

If you have read our earlier breakdown of tax gain harvesting vs. tax loss harvesting, you know the idea in principle. This post is the worked example: real 2026 brackets, a real-looking brokerage account, and the arithmetic you would do at the kitchen table in mid-November.

The Scenario: A Couple With $37,000 of Unrealized Gains

Meet Maya and Daniel, a fictional couple built from typical numbers. Both work full time. Their 2026 situation looks like this:

• Combined W-2 wages: $118,000
• Pre-tax 401(k) contributions: $16,000 (so $102,000 of wages shows up in box 1)
• Savings account interest: $800 (ordinary income)
• Qualified dividends from their taxable brokerage account: $1,000
• A taxable brokerage account worth $85,000, invested in a single total-market index fund bought between 2019 and 2022, with a total cost basis of $48,000

That last line is the interesting one. They are sitting on $37,000 of unrealized long-term gains. They have no plans to sell. Their instinct, like most people’s, is to leave the account alone, because selling “causes taxes.”

That instinct is not unusual. The Federal Reserve’s 2022 Survey of Consumer Finances found that a record 58% of U.S. families owned stocks directly or indirectly, yet most of that ownership sits in retirement accounts where gain harvesting is irrelevant. For the households that also hold a taxable brokerage account, the default behavior is to never realize a gain until a big purchase or retirement forces it — often in a year when the gain lands in the 15% bracket instead of the 0% one.

How the 0% Capital Gains Bracket Actually Works in 2026

The key thing to understand before any tax gain harvesting: long-term capital gains and qualified dividends stack on top of your ordinary income. Your wages and interest fill the bottom of the bracket structure first. Gains fill whatever is left. The 0% rate applies only to the slice of gains that fits under the threshold.

Here are the 2026 long-term capital gains thresholds, based on taxable income (after the standard or itemized deduction):

Source: IRS Revenue Procedure 2025-32, as summarized by Kiplinger and the Tax Foundation. The 2026 standard deduction is $16,100 for single filers and $32,200 for married couples filing jointly.

Two details trip people up. First, the threshold is taxable income, not salary. Someone earning $120,000 can easily be under $98,900 after 401(k) contributions and the standard deduction. Second, only gains on assets held more than one year qualify. IRS Topic 409 is explicit that anything held one year or less is short-term and taxed as ordinary income — no 0% rate at all.

Running Maya and Daniel’s Tax Gain Harvesting Numbers

Here is how their 2026 return stacks up before they sell anything:

So Maya and Daniel can realize up to $27,300 of long-term gains in 2026 and owe zero federal tax on them. Their $1,000 of qualified dividends is already inside the 0% band too, which is why it is counted in taxable income above.

Why they should not use all $27,300

Taxable income in mid-November is an estimate. Index funds and mutual funds commonly pay a dividend in December, a year-end bonus can be bigger than expected, and interest rates move savings income around. If they overshoot the threshold, nothing catastrophic happens — only the dollars above $98,900 are taxed at 15% — but there is no reason to pay that. A reasonable buffer is $1,500 to $3,000. They settle on harvesting $25,000, leaving $2,300 of cushion.

How many shares to sell

Their account is 43.5% unrealized gain ($37,000 ÷ $85,000). Using average cost, realizing $25,000 of gain means selling about $57,400 of fund shares ($25,000 ÷ 0.435). In practice they would use specific lot identification and sell the lots with the highest gain per dollar, which lets them realize the same $25,000 while selling fewer shares. Then they immediately buy the same fund back with the proceeds.

The wash sale rule does not get in the way here. Under IRS Publication 550, wash sale restrictions apply when you sell at a loss and repurchase within 30 days. Selling at a gain and buying back the same day is allowed.

What they actually gained

Their portfolio is still worth $85,000 and still holds the same fund. The only thing that changed is the cost basis, which rises from $48,000 to $73,000. Their unrealized gain drops from $37,000 to $12,000.

When they eventually sell — for a house down payment, a career break, or retirement income — that $25,000 will never be taxed again. If those future sales would have landed in the 15% bracket, the harvest saves $3,750 in federal tax ($25,000 × 15%). If they repeat it every year their income allows, the savings compound across a decade or more.

Who Else Has 0% Room? Four Quick Profiles

Maya and Daniel are a middle-of-the-road example. The strategy gets much more powerful in years when ordinary income is unusually low. Using the same 2026 thresholds and standard deductions:

*Includes $1,000 of qualified dividends. Figures are simplified illustrations using the 2026 standard deduction and ignore state taxes, credits and the additional deductions available to filers age 65 and older (which would create even more room).

The career-break and early-retiree rows are where tax gain harvesting shines. A year between jobs, a sabbatical, the gap between leaving work and starting Social Security — these are the years when tens of thousands of dollars of gains can be reset at zero. People who plan those transitions around a Roth conversion strategy should know that conversions and gain harvesting compete for the same low-bracket space: conversion dollars are ordinary income and fill the bottom of the stack first, shrinking the room left for 0% gains.

I started tracking my own “0% room” in a small spreadsheet a few years ago, mostly because the engineer in me hates leaving an optimization on the table when the inputs are known. The honest result: in high-earning years there was nothing to harvest, and the exercise took five minutes to confirm that. In a lighter year it found real money. Running the numbers is cheap; I automated the projection with a script that pulls year-to-date pay stub data and estimates December dividends, which is the kind of boring automation that pays for itself quietly.

The Hidden Costs of Tax Gain Harvesting

A 0% federal rate does not mean the move is free for everyone. Realized gains raise your adjusted gross income, and AGI feeds into a surprising number of other calculations. Before selling, check each of these:

State income tax. Most states that levy an income tax treat capital gains as ordinary income and offer no 0% band. Maya and Daniel’s $25,000 harvest would cost about $1,250 in a state with a 5% flat rate. That is still a good trade against $3,750 of future federal tax, but it is not zero — and in a high-tax state, the math narrows considerably. Residents of states without an income tax keep the full benefit.

ACA marketplace subsidies. If you buy health insurance on the marketplace, premium tax credits are based on modified AGI. Harvested gains count. An early retiree who adds $40,000 of gains could see subsidies shrink by thousands of dollars, wiping out the benefit entirely. This is the single most common reason gain harvesting backfires for people between jobs.

Social Security taxation. For retirees already collecting benefits, capital gains increase “provisional income,” which can make more of each Social Security check taxable as ordinary income. That indirect tax can turn a “0%” gain into an effective 15% to 25% marginal cost.

Medicare IRMAA and financial aid. Medicare Part B and D surcharges use your MAGI from two years earlier, and the FAFSA uses prior-prior-year income. Most middle-income households will not cross the relevant thresholds, but a large one-time harvest could.

Capital loss carryforwards. This is the subtle one. If you have unused losses from a prior tax-loss harvesting round, those losses offset your gains first — before the 0% rate even applies. Harvesting gains in that situation burns losses that could otherwise offset up to $3,000 of ordinary income per year (the limit in IRS Topic 409). You would be trading a valuable deduction for a 0% rate you were going to get anyway.

Step-by-Step: Harvesting Gains Before December 31

If the numbers work for you, here is the order of operations Maya and Daniel would follow this month:

1. Estimate 2026 taxable income. Take year-to-date wages from your latest pay stub, project the remaining pay periods, subtract pre-tax 401(k) and HSA contributions, add interest and expected dividends, and subtract your standard deduction ($32,200 MFJ, $16,100 single).
2. Find your room. Subtract that taxable income from your 0% threshold ($98,900 MFJ, $49,450 single, $66,200 head of household). Subtract a $1,500–$3,000 buffer.
3. Check for loss carryforwards. Look at lines 6 and 14 of last year’s Schedule D or your tax software’s carryover worksheet. If you have one, gain harvesting probably isn’t worth it this year.
4. Check the side effects. ACA subsidies, state tax, Social Security, IRMAA. If any of them apply, model the full cost before selling.
5. Set your brokerage to specific lot identification. Pick lots held more than one year with the largest gains. Confirm the holding period on each lot before placing the trade.
6. Sell and rebuy the same day. There is no wash sale issue for gains. Rebuying immediately keeps you invested and preserves your asset allocation.
7. Save the trade confirmations. Your broker will report the sale on Form 1099-B with the new, higher basis for the repurchased shares. Keep confirmations in case the 1099-B needs correcting.
8. Repeat next year. Thresholds are inflation-adjusted every year, so your room will shift. Put a reminder on your calendar for early November.

One planning note: gain harvesting only makes sense inside a taxable brokerage account. In a 401(k) or IRA, gains are never taxed as capital gains at all, which is part of why getting your asset location strategy right matters — the less tax-inefficient stuff you hold in taxable accounts, the less often you need to think about any of this.

This article is for educational purposes and is not tax advice. The couple described is a fictional illustration. Confirm your own figures with tax software or a qualified tax professional before trading.

Photo by Jakub Żerdzicki on
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Written by Chris Steve

Chris Steve is a software engineer with a deep interest in personal finance, behavioral economics, and AI. He started Money & Planet to share clear, research-backed money guides — the kind that explain the math instead of pushing products. His writing focuses on long-term wealth building, the psychology behind spending and investing decisions, and the practical tools regular people can use to make smarter financial choices.