How to actually harvest a tax loss

Tax loss harvesting means selling an investment at a loss, then using that loss to reduce taxes you owe on other investment gains or income. The process itself has four concrete steps: identify which positions are underwater, sell them, buy a replacement investment, and report the loss on your tax return.

The timing matters because you must sell in the same calendar year you want to use the loss. If you sell a losing position in December, you can use that loss against gains from January through December of that same year. A loss you realize in January of the following year cannot offset gains from the prior year.

You do not need permission from anyone to harvest a loss — it is a transaction you execute in your brokerage account the same way you would any other sale. The IRS does not pre-approve it. You straightforward sell, buy the replacement, and then report what happened when you file your return.

Key Takeaways

  • Sell a position worth less than you paid for it, then buy a similar but not identical replacement investment within 30 days before or after the sale to avoid the wash-sale rule.
  • The loss can offset capital gains dollar-for-dollar, and any remaining loss can reduce ordinary income by up to $3,000 per year, with excess losses carrying forward to future years.
  • You must complete the sale and replacement purchase in the same calendar year to use the loss on that year's tax return.
  • The wash-sale rule disallows the loss if you buy back the same or substantially identical security within 30 days of the sale, so a replacement must be genuinely different.

Identifying positions that have lost value

Start by looking at your brokerage account statements or the account dashboard itself. Most brokers show your cost basis (what you paid) and current value side by side. Any position where current value is lower than cost basis is a candidate.

You can harvest losses throughout the year as you notice them, or you can do a systematic review near the end of the year when you have a clearer picture of your total gains and losses. Some people harvest opportunistically whenever a position drops; others wait until November or December to see what they need.

The size of the loss matters only if you are trying to offset a specific gain or income amount. A $500 loss is just as valid as a $5,000 loss — it straightforward offsets less. There is no minimum loss required to harvest.

Selling the losing position

Once you have identified a position to harvest, place a sell order in your brokerage account for the full position or a portion of it. You can harvest losses from part of a holding if you own multiple lots at different prices, though this requires specifying which lot you are selling — most brokers call this "specific lot identification."

The sale settles in the normal timeframe for your account type. Stock sales typically settle in two business days; mutual fund sales may take longer depending on the fund. The loss is realized on the settlement date, not the trade date, though for tax purposes the year of the loss is determined by when you placed the order.

After the sale completes, you will have cash in your account. This is the moment to move quickly to the replacement purchase, because the 30-day wash-sale window begins when ready.

Buying a replacement investment within the wash-sale window

The wash-sale rule says the IRS will disallow your loss if you buy back the same security or a substantially identical one within 30 days before the sale or 30 days after it. That is a 61-day window total: 30 days before, the sale date itself, and 30 days after.

To avoid triggering the rule, buy something different. If you sold a specific stock, buy a different stock or an ETF that tracks a similar sector or market segment. If you sold a bond fund, buy a different bond fund with a different strategy or duration. The replacement does not have to be identical in performance — it just has to be genuinely different in the eyes of the IRS.

You must complete this purchase within the 30-day window after the sale. If you wait 31 days, the wash-sale rule no longer applies, but you have also lost the benefit of staying invested during that time. Most people buy the replacement within days of the sale.

The replacement investment can be in the same account or a different account. It can be in a taxable account, a traditional IRA, a Roth IRA, or any other account type you own. The rule applies across all your accounts.

Reporting the loss on your tax return

When you file your tax return, you will report the sale on Schedule D (Capital Gains and Losses). Your brokerage will send you a Form 1099-B showing all your sales for the year, including the losing position you harvested. You use this form to fill out Schedule D.

On Schedule D, list the security name, the date you bought it, the date you sold it, your cost basis, the sale proceeds, and the loss. The form calculates your net gain or loss across all your sales for the year.

If your total losses exceed your total gains, you can use up to $3,000 of the excess loss to reduce your ordinary income (wages, salary, interest, and other non-investment income) in that tax year. Any loss beyond $3,000 carries forward to the next year, where you can use another $3,000 against ordinary income, and so on until the loss is fully used.

If you have no gains to offset and your income is below $3,000, you still report the loss on Schedule D — it just carries forward rather than reducing your current-year taxes.

What happens if you accidentally trigger the wash-sale rule

If you buy back the same or substantially identical security within 30 days, the IRS disallows the loss in the year you sold it. The loss does not disappear — instead, it gets added to the cost basis of the replacement security you bought.

This means you will have a higher cost basis on the new position, which reduces any future gain (or increases any future loss) when you eventually sell it. The tax benefit is deferred rather than lost, but you lose the when ready deduction.

The IRS does not penalize you for a wash-sale violation beyond disallowing the loss. You do not owe extra tax or interest if it happens unintentionally. However, if you deliberately trigger a wash sale to claim a loss you know you should not claim, that crosses into tax evasion.

Timing considerations across different account types

Tax loss harvesting works only in taxable accounts. In a traditional IRA, Roth IRA, 401(k), or other tax-advantaged account, you cannot harvest losses because gains and losses inside these accounts do not affect your taxes in the first place.

If you have both taxable and tax-advantaged accounts, you can harvest losses in the taxable account and buy the replacement in a tax-advantaged account without triggering the wash-sale rule. The rule applies across accounts you own, but it applies only to the same security — buying a different security in a different account is always safe.

The calendar year important date is firm. Any loss you realize on December 31 can be used on that year's return. Any loss realized on January 1 of the next year cannot. If you are considering harvesting a loss near year-end, confirm the settlement date with your broker to may support the sale settles before midnight on December 31.

Frequently Asked Questions

Can I harvest a loss and buy back the exact same investment after 30 days?

Yes. The wash-sale rule applies only within the 30-day window before and after the sale. If you wait 31 days or more, you can buy back the identical security without disallowing the loss. Many people harvest a loss, hold cash or a different investment for a month, then return to their original position.

What counts as substantially identical for the wash-sale rule?

The IRS considers the same stock or mutual fund substantially identical to itself. A different share class of the same fund is also substantially identical. However, a different stock, a different fund, or an ETF tracking a similar index is not substantially identical. When in doubt, choose a replacement that is clearly different in name and strategy.

Do I have to harvest losses every year?

No. You harvest losses only when you have positions that are underwater and you want to use the loss to offset gains or income. If all your investments are up in value, or if you have no gains to offset, there is nothing to harvest. You can also choose to harvest some years and not others.

What if my loss is larger than my gains for the year?

You can use up to $3,000 of the excess loss to reduce your ordinary income in that year. Any loss beyond $3,000 carries forward indefinitely to future years, where you can use another $3,000 per year against ordinary income until the loss is fully used.

Does harvesting a loss affect my cost basis on the replacement investment?

Only if you trigger the wash-sale rule. If you buy a genuinely different replacement, your cost basis on the new investment is straightforward what you paid for it. If you accidentally buy back the same security within 30 days, the disallowed loss gets added to the cost basis of the replacement, which defers the tax benefit to a future sale.