Tax loss harvesting is worth it only if you have investment losses to use and enough taxable income to benefit from them

Tax loss harvesting reduces your federal income tax bill by using investment losses to offset gains or income. Whether it makes sense depends on three concrete facts: whether you actually have losses in your portfolio, how much taxable income you have to offset, and what you pay in fees or trading costs to execute the strategy. If you have no losses, or your income is too low to benefit from deductions, harvesting costs you money for no tax savings. If you have substantial losses and high taxable income, it can save hundreds or thousands of dollars per year.

The math is straightforward. A loss of $10,000 can offset $10,000 in capital gains or, if you have no gains, reduce your ordinary income by up to $3,000 in a single tax year (with unused losses carried forward). At a 24% federal tax rate, that $3,000 deduction saves you $720. At a 37% rate, it saves $1,110. But if you pay $50 in trading commissions or $200 in advisory fees to harvest that loss, your net savings shrink. And if you have no gains to offset and your income is already low enough that the $3,000 deduction doesn't help much, the strategy may not be worth the effort.

Key Takeaways

  • Tax loss harvesting only saves money if you have investment losses and enough taxable income or capital gains to benefit from offsetting them.
  • A $10,000 loss can offset $10,000 in gains or reduce ordinary income by up to $3,000 per year, with unused losses carried to future years.
  • The wash-sale rule prevents you from buying the same or substantially identical security within 30 days before or after the sale, which limits how quickly you can reinvest.
  • If you pay fees or commissions to harvest losses, those costs must be smaller than the tax savings or the strategy loses money.
  • Harvesting works best for people with high taxable income, substantial investment losses, and low trading costs.

When you have capital gains to offset

If you sold investments at a profit this year, tax loss harvesting is most straightforward. A loss directly cancels a gain dollar-for-dollar, with no limit. Sell a stock at a $5,000 loss and a mutual fund at a $5,000 gain, and your net capital gain is zero. You owe no tax on either transaction. This is the cleanest use case because there is no phase-out, no annual cap, and no question about whether the deduction helps you.

The catch is the wash-sale rule. You cannot buy the same stock or a substantially identical one within 30 days before or after the sale. If you sell Apple at a loss on December 15 and buy it back on January 10, the IRS disallows the loss. You can buy a similar but not identical security — a different tech stock, or an index fund that holds tech — and avoid the wash sale. But that means your portfolio composition changes, at least temporarily. If you want to stay in the same investment, you must wait 31 days.

When you have no gains but high ordinary income

If you did not sell anything at a profit this year, you can still use losses to reduce your ordinary income — wages, self-employment income, interest, dividends. But the deduction is capped at $3,000 per year. Any unused loss carries forward to future years, so a $10,000 loss becomes a $3,000 deduction this year and a $7,000 deduction next year (assuming you have no gains next year either).

This matters because the tax savings depend on your tax bracket. At a 12% federal rate, a $3,000 deduction saves $360. At a 35% rate, it saves $1,050. If you are in a low tax bracket — or have little income to begin with — the deduction is worth less. And if you have no income or losses in future years, the carried-forward loss may never be used. For high-income earners with substantial losses, the strategy still works; you just spread the benefit across multiple years.

The wash-sale rule and reinvestment timing

The wash-sale rule is the main operational constraint. After you sell at a loss, you have a 30-day window — 30 days before the sale, 30 days after — during which you cannot buy the same security or one substantially identical to it. Buying a different investment in the same category usually works. If you sell a specific stock fund at a loss, you can buy a broad market index fund. If you sell a bond fund, you can buy a different bond fund with different holdings.

The IRS does not define "substantially identical" with perfect precision, which creates gray areas. Buying the same fund from a different provider, or buying a fund with nearly identical holdings, may or may not trigger the rule depending on the facts. To be safe, most people move to a genuinely different investment for 31 days, then move back if they want to. This means your portfolio is temporarily different from your target allocation, which introduces a small risk: if the market moves sharply in those 31 days, you may miss gains or take unexpected losses in the replacement investment.

Fees and costs that eat into savings

If you do the harvesting yourself through a brokerage with no trading commissions, the only cost is your time. If you use a financial advisor, robo-advisor, or tax software that charges a fee to harvest losses, that fee must be smaller than the tax savings or you lose money on the trade.

A robo-advisor that charges 0.25% of assets per year and harvests losses for you may save you $500 in taxes but cost you $250 in advisory fees, netting $250. That is still worth it. But if the same advisor charges 1% and you have a small portfolio, the fee may exceed the tax savings. Some tax software charges $50 to $200 per harvest, which makes sense only if the tax savings are larger. Calculate the expected tax savings before you pay for the service.

Trading costs matter too. If your brokerage charges $5 per trade and you sell and buy four times per year to harvest losses and avoid wash sales, you spend $20 in commissions. Most major brokerages now offer commission-free trading, so this is less common, but it is worth checking your statement.

Situations where harvesting does not pay

Tax loss harvesting makes no sense if you have no losses. If your portfolio is up in value, there is nothing to harvest. It also does not help if you have losses but no income or gains to offset them. A retiree with $30,000 in annual Social Security income and a $50,000 investment loss can use only $3,000 of the loss per year; the rest carries forward indefinitely. If the retiree never has capital gains and dies before using all the losses, the unused portion disappears. The heirs get a stepped-up cost basis and do not inherit the loss.

Harvesting also does not help if you are in a very low tax bracket. A person earning $25,000 per year in the 12% federal bracket saves only $360 per $3,000 deduction. If you pay $100 in fees to harvest, you net $260. That is still positive, but the incentive is smaller. And if you are subject to the Net Investment Income Tax (3.8% on investment income above certain thresholds for high earners), harvesting becomes more valuable because the tax savings are larger.

How to decide if it is worth your time and money

Start with the numbers. Calculate your expected tax savings: take your losses, apply the $3,000 annual cap if you have no gains, and multiply by your marginal tax rate (the rate on your last dollar of income). Then subtract any fees or commissions. If the result is positive and larger than the effort required, it is worth doing.

If you have a financial advisor or use tax software, ask them to estimate the tax savings before you pay for harvesting. If you are doing it yourself, use a spreadsheet or a calculator. The calculation takes 10 minutes and tells you whether the strategy makes sense for your situation. If you have small losses, low income, or high fees, the answer is often no. If you have substantial losses, high income, and low costs, the answer is usually yes.

Frequently Asked Questions

Can I harvest losses in a retirement account like a 401(k) or IRA?

No. Retirement accounts are tax-deferred, so losses inside them do not reduce your taxable income. You cannot harvest losses in these accounts. Tax loss harvesting only works in taxable brokerage accounts.

What happens to losses I do not use in the current year?

Unused losses carry forward to future years indefinitely. A $10,000 loss used as a $3,000 deduction this year leaves $7,000 to deduct next year. You can use carried-forward losses in any future year when you have income or gains, but if you die with unused losses, they expire and cannot be passed to heirs.

Does harvesting losses affect my income for purposes of other benefits or deductions?

Yes. Losses reduce your adjusted gross income (AGI), which can affect your may be able to access for other tax benefits like the Earned Income Tax Credit, education credits, or deductions that phase out at higher incomes. In some cases, lowering your AGI through harvesting can increase your total tax benefit. In others, it may reduce benefits. Run the numbers both ways before you harvest.

If I harvest a loss and buy a similar fund, will the IRS challenge me?

The IRS challenges wash-sale violations when the securities are clearly identical or when the pattern suggests intent to evade the rule. Buying a genuinely different fund — different holdings, different manager, different category — is safe. Buying the same fund from a different provider or a fund with nearly identical holdings is riskier. When in doubt, wait 31 days or consult a tax professional.

Should I harvest losses even if I am not sure I will have income to use them?

If you expect to have income or gains in future years, harvesting now locks in the loss and lets you use it when you need it. If you are uncertain about future income, harvest anyway — the loss does not expire, and you can use it whenever your situation changes. The only exception is if you expect to die soon with unused losses; in that case, harvesting provides no benefit to you or your heirs.