Tax-loss harvesting means realizing an investment loss as part of a tax and portfolio plan. In a U.S. taxable account, an eligible loss may offset gains under applicable rules. The investment decision, replacement exposure and tax treatment must be evaluated together.
A loss in an IRA is not harvested in the same manner as a loss in a taxable brokerage account. This guide addresses general U.S. stock and securities rules; it does not supply a personal tax calculation or assume identical treatment in other countries.
In This Guide
- 1 Start with the economic decision
- 2 A simplified example
- 3 Understand the wash-sale window
- 4 Use a pre-trade checklist
- 5 Timing and future consequences
- 6 When to get a specific review
- 7 A partial-repurchase wash-sale example
- 8 Use a pre-trade calendar and a post-trade reconciliation
- 9 Compare tax benefit with the investment cost
- 10 Sources
Start with the economic decision
Ask whether you still want the exposure, whether the position fits the portfolio and what selling will cost. A tax benefit cannot repair a fundamentally unsuitable investment. Consider trading spreads, commissions, changes in allocation and the possibility of being out of the market.
A simplified example
A hypothetical investor buys shares for $10,000 and later sells them for $7,000. Ignoring transaction adjustments, the realized loss is $3,000. If the investor also has $3,000 of gains that can be offset under the applicable netting rules, the loss can reduce those gains.
The tax saving is not automatically $3,000. At an illustrative 15% applicable rate, a $3,000 offset would correspond to $450 of tax reduction. Actual treatment depends on holding periods, other gains and losses, carryovers and the investor’s circumstances.
Understand the wash-sale window
The IRS describes a wash sale involving a loss on stock or securities and acquisition of substantially identical stock or securities within 30 days before or after the sale. The review therefore extends to purchases before the sale as well as afterwards.
Dividend reinvestments and purchases in other relevant accounts can complicate the analysis. A replacement fund is not automatically acceptable merely because its name or ticker differs. “Substantially identical” is a tax standard that requires careful evaluation.
Use a pre-trade checklist
- Identify the tax lots, acquisition dates and adjusted basis.
- Review recent purchases and automated reinvestments.
- Check relevant household and retirement-account transactions.
- Define the replacement exposure and its tax implications.
- Estimate costs and the benefit using your actual tax situation.
- Keep the confirmations and reconcile year-end reporting.
Do not assume a single broker’s report captures transactions at every other institution. A complete transaction record is important when reviewing wash-sale adjustments.
Timing and future consequences
Harvesting can shift the timing of taxes, rather than permanently remove them. A replacement investment’s basis and later sale can affect future gains. The value of a deduction or offset also depends on when it can be used.
For U.S. individuals, the IRS explains the annual deduction limit for excess net capital losses and carryforward treatment. Check the current instructions and your filing status instead of treating every realized loss as an immediate cash refund.
When to get a specific review
Seek qualified tax advice for cross-account repurchases, options, retirement-account replacements, complex funds, digital assets, business holdings or cross-border residency. Avoid applying the stock wash-sale analysis to every asset without checking its legal treatment.
Coordinate the trade with portfolio rebalancing and the broader capital-gains planning process. Keep the investment objective visible throughout the tax calculation.
A partial-repurchase wash-sale example
For a simplified U.S. taxable-account example, assume 100 identical shares have a total $5,000 basis and are sold for $4,000, creating a $1,000 loss. Within the wash-sale window, 20 replacement shares are purchased for $900. Assume this is the only relevant replacement purchase and the shares are correctly matched.
The loss allocated to those 20 shares is 20 divided by 100 times $1,000, or $200. Under the ordinary taxable replacement-share treatment, that disallowed loss is added to their $900 cost, producing $1,100 basis. The other $800 of the original loss is not disallowed by that particular replacement purchase, but its ultimate use still depends on other transactions and the tax rules.
This example excludes IRA replacements, other purchases, corporate actions, fees and cross-account complications. Do not assume a loss disallowed because of an IRA purchase receives the same basis treatment. Check the complete household trading record with a qualified adviser.
Use a pre-trade calendar and a post-trade reconciliation
| Stage | Record to check |
|---|---|
| Before selling | Tax lots, basis, dates, recent purchases and automatic investment instructions |
| During the relevant window | Purchases across applicable accounts, including automatic reinvestments |
| After transactions settle | Replacement lots, adjustments and the investment exposure that remains |
| Before filing | Broker records reconciled with facts the broker may not know |
A broker report is a starting point, not evidence that every cross-account purchase has been considered. Save the order confirmations and the basis calculation so that the later return can be checked.
Compare tax benefit with the investment cost
Keep the portfolio objective visible. A sale that changes exposure, incurs spreads or creates a less suitable holding can have a cost even when a loss is usable. A tax benefit depends on actual gains, rates and eligibility; a realized loss alone does not establish a refund of a fixed amount.
Sources
- IRS Publication 550: investment income, expenses and wash sales
- IRS Topic 409: capital gains and losses
Reviewed October 11, 2026. Worked examples are hypothetical. Educational information; individual circumstances and jurisdiction matter.
