Wash Sale Rule: What It Is & How to Avoid It
In November 2023, David sold 200 shares of a beaten-down semiconductor stock at a $12,400 loss, planning to claim it on his tax return. Two weeks later, convinced the stock had bottomed, he bought back the same 200 shares. When he filed his taxes, his tax preparer delivered the news: the $12,400 loss was disallowed under the wash sale rule. He had unknowingly erased a deduction worth $2,728 in federal tax savings. Here is everything you need to know to avoid the same mistake.
Key Takeaways
- →IRS Section 1091 disallows a capital loss if you buy a substantially identical security within 30 days before or after the sale — a 61-day blackout window.
- →The disallowed loss is NOT permanently gone — it is added to the cost basis of the replacement security.
- →The wash sale rule applies across ALL accounts you control — including your IRA. Buying in an IRA to replace a sold position in taxable can permanently destroy the loss.
- →Cryptocurrency is currently exempt from the wash sale rule in 2026 — crypto is property, not a security under IRS Notice 2014-21.
- →Brokerages are required to report wash sales on Form 1099-B but only within the same account — cross-account tracking is your responsibility.
The Legal Foundation: IRC Section 1091
The wash sale rule is codified at Internal Revenue Code Section 1091. Enacted in its modern form decades ago, the rule was designed to prevent a specific type of tax arbitrage: selling a security at a loss purely to claim the tax deduction, then immediately buying it back to maintain the same economic position. Without the rule, investors could repeatedly churn positions to generate endless paper losses while never changing their actual holdings.
The rule states that a loss is disallowed if, within 30 days before or after the date of the sale, the taxpayer "has acquired (by purchase or by an exchange on which the entire amount of gain or loss was recognized by law), or has entered into a contract or option so to acquire, substantially identical stock or securities." The IRS operationalizes this as a 61-day window: 30 days before the sale, the day of the sale itself, and 30 days after.
Treasury Regulation 1.1091-1 and IRS Publication 550 (Investment Income and Expenses) provide additional guidance. IRS Publication 550 is the primary reference document for investors navigating wash sale questions and includes worked examples of common scenarios.
The 61-Day Window: Visualized
The timing of the wash sale rule trips up investors because many assume it is a 30-day rule. It is not. The window extends symmetrically: 30 days before AND 30 days after the sale date, producing a continuous 61-day blackout period:
| Period | Days | Example (Sale on October 15) |
|---|---|---|
| Pre-sale window | 30 days before | September 15 – October 14 |
| Day of sale | Day 0 | October 15 |
| Post-sale window | 30 days after | October 16 – November 14 |
| Total blackout | 61 days | September 15 – November 14 |
| Safe to repurchase | Day 62+ | November 15 or later |
Notice that the pre-sale window applies before you even sell. If you purchased 100 shares of a stock on October 1 and then sold a different lot of the same stock at a loss on October 15, the October 1 purchase falls within the 30-day pre-sale window and triggers a wash sale. The IRS disallows the loss even though you bought the shares before deciding to sell. This catches many investors who make purchases for independent reasons without realizing a prior purchase will contaminate a planned loss sale.
What "Substantially Identical" Actually Means
The IRS has never published a precise definition of "substantially identical" for purposes of the wash sale rule. The standard is based on facts and circumstances. This ambiguity creates both planning opportunities (using similar-but-different securities to maintain exposure) and genuine risk (assuming two securities are different when the IRS might disagree).
Based on IRS guidance, court cases, and revenue rulings, the following general framework applies:
| Security Pair | Substantially Identical? | Notes |
|---|---|---|
| Same stock, same company | Yes — always | No ambiguity |
| Two ETFs tracking identical index (e.g., SPY vs IVV, both S&P 500) | Likely yes | Same underlying securities and weights |
| S&P 500 ETF vs Total Market ETF (e.g., VOO vs VTI) | Probably no | Different index; VTI includes 3,500+ stocks |
| Individual stock vs sector ETF containing that stock | Probably no | Diversified fund ≠ single stock position |
| Mutual fund and its ETF share class (same fund) | Likely yes | Same underlying portfolio |
| Bond fund vs bond ETF with similar duration and credit quality | Uncertain | Facts-based; different holdings help |
| Cryptocurrency (Bitcoin sold, Bitcoin repurchased immediately) | Not applicable | Crypto is property, not a security under IRS Notice 2014-21 |
The safest approach is to replace a harvested position with a security that tracks a meaningfully different index with demonstrably different underlying holdings. The riskier approach — swapping between two funds tracking the exact same index — relies on a legal ambiguity that has not been definitively resolved against taxpayers but theoretically could be.
What Happens to the Disallowed Loss?
Many investors assume a wash sale loss is permanently lost. It is not. Under IRC Section 1091(d), the disallowed loss is added to the cost basis of the replacement security. This means the loss is deferred, not eliminated — it will be recognized when you eventually sell the replacement security (provided you do not trigger another wash sale).
Example: You sell 100 shares of XYZ Corp at $45/share, realizing a $5,000 loss ($95 purchase price − $45 sale price × 100 shares). One week later, you repurchase 100 shares at $48/share. The $5,000 loss is disallowed. Your cost basis on the new shares is $48 + ($5,000 ÷ 100) = $48 + $50 = $98 per share. When you eventually sell those shares at, say, $70, your recognized loss is $98 − $70 = $28 per share, or $2,800 — capturing the original $5,000 loss partially, plus the new period's movement.
The holding period of the replacement security is also extended. It includes the holding period of the sold security, which can affect whether your eventual sale qualifies as long-term or short-term. This is another mechanism the IRS uses to ensure wash sales do not artificially convert short-term gains into long-term gains by resetting the clock.
The IRA Account Trap: Where the Loss Is Truly Gone
The most dangerous wash sale scenario involves IRA accounts. The rule applies across all accounts you control — including traditional IRAs, Roth IRAs, and IRAs held by your spouse. If you sell a security in your taxable brokerage account at a loss and then purchase the same (or substantially identical) security in your IRA within the 61-day window, the wash sale rule applies and the loss is disallowed.
The catastrophic aspect is this: when the replacement purchase is inside an IRA, the disallowed loss cannot be added to the IRA's cost basis — tax-advantaged accounts do not track cost basis the same way taxable accounts do. The loss is permanently gone with no future offset available. This is explicitly confirmed in IRS Publication 550: "If you have a wash sale of stock you acquired by purchase, the disallowed loss is added to the cost of the new stock...However, the additional basis in stock or securities acquired in an IRA isn't tracked separately."
This rule catches investors who manage multiple accounts — particularly those who automate dividend reinvestment in an IRA while manually harvesting losses in a taxable account holding similar positions. Review all accounts before executing a harvest to confirm no wash sale conflicts exist. For a broader view of how losses interact with your total tax picture, see our complete Tax-Loss Harvesting guide.
Wash Sales and Cryptocurrency in 2026
The wash sale rule under IRC Section 1091 applies only to "stock or securities." Under IRS Notice 2014-21, cryptocurrency is classified as property, not a security. This means, as of 2026, the wash sale rule does not apply to cryptocurrency transactions. An investor can sell Bitcoin at a $30,000 loss on Monday morning and repurchase the same amount of Bitcoin on Monday afternoon — and claim the full $30,000 loss on their tax return.
This represents a significant tax advantage that stock and bond investors do not have. During periods of crypto market volatility, sophisticated investors execute "harvest and rebuy" trades specifically to capture the tax loss while maintaining full exposure. A $30,000 harvested loss saves a taxpayer in the 22% bracket $4,500 in federal income tax — obtained without any change in economic position.
Legislative risk is real. Proposals to apply wash sale rules to crypto have been included in multiple pieces of legislation since 2021. The Senate Finance Committee's 2021 budget reconciliation package included such a provision. While none has passed as of 2026, investors using crypto tax-loss harvesting strategies should treat this exemption as temporary and stay current on tax legislation. For the full picture on crypto taxation, our 2026 Crypto Tax Guide covers all current rules.
How Brokerages Report Wash Sales
Brokerages are required to report wash sales on Form 1099-B in Box 1g. When a wash sale is triggered within the same account at the same brokerage, the 1099-B will show the disallowed loss amount. Box 5 will be checked, indicating the sale "did not result in a deductible loss." The adjusted cost basis of the replacement shares is reported in Box 1e.
However, brokerages are only required to track wash sales within the same account at their institution. If you have positions at multiple brokerages, or if you trigger a wash sale between a taxable account and an IRA at the same institution, the cross-account tracking may not appear on your 1099-B. The IRS holds you — not the brokerage — responsible for identifying cross-account wash sales and correctly reporting them on your return.
For investors with multiple accounts, the only reliable approach is to maintain a personal spreadsheet or use tax software that consolidates all account activity. All wash sale adjustments are reported on Form 8949, Columns (b) and (g), with code "W" in column (f) to indicate the disallowed loss.
5 Practical Rules to Avoid Wash Sales
- Mark your calendar immediately after every harvest. Note the date 31 days out. Do not repurchase the same security before that date in any account.
- Choose replacement securities that track different indexes. Replacing an S&P 500 fund with a total market fund eliminates most wash sale ambiguity while maintaining broad equity exposure.
- Audit your IRA activity before harvesting. If dividend reinvestment in your IRA purchased shares of the same stock within the last 30 days, your intended harvest in the taxable account is already contaminated. Suspend dividend reinvestment for at-risk positions during harvesting periods.
- Coordinate with a spouse. Securities purchased by your spouse within the wash sale window are treated as purchased by you. If spouses manage separate brokerage accounts independently, this creates inadvertent wash sales that neither discovers until tax time.
- Use tax software or a tax professional to reconcile 1099-Bs. Multiple 1099-Bs from different institutions will not automatically cross-reference each other. Software like TurboTax Premier or H&R Block Deluxe can import all 1099-Bs and flag potential cross-account wash sales, though manual review is still advisable for large or complex portfolios.
Wash Sales Across Year-End: A Special Problem
December harvesting creates a specific timing trap. If you harvest a loss on December 15, the post-sale 30-day window extends to January 14 of the next year. Any repurchase of the same security in January — in a new tax year — still triggers a wash sale disallowance on your December loss. The disallowed amount is carried over to adjust your January cost basis, but the loss cannot be claimed on the December year's return.
This means December 31 harvests are the most dangerous. A December 31 sale creates a wash sale window that runs through January 30. Investors planning year-end harvests should execute no later than November 30 if they want a clean January in which they can repurchase without restriction. Alternatively, harvesting in December is fine if you use a truly different replacement security immediately and wait the full 31+ days to reenter the original position.
Frequently Asked Questions
If my loss is disallowed by the wash sale rule, is the money permanently gone?
No — unless the replacement purchase was inside an IRA. For taxable account replacements, the disallowed loss is added to the cost basis of the replacement security under IRC Section 1091(d). You recover the loss when you eventually sell the replacement at a price that reflects the higher basis. The loss is deferred, not destroyed. The exception: if you bought the replacement in an IRA, the loss cannot be tracked and is permanently lost.
Does the wash sale rule apply if I sell in a taxable account and buy in a Roth IRA?
Yes, and this is one of the most costly wash sale scenarios. The rule applies across all accounts you own or control, including Roth IRAs. If you sell a security at a loss in your taxable brokerage and buy the same security in your Roth IRA within 61 days, the loss is disallowed. Worse, because the Roth IRA does not track cost basis in the same way as a taxable account, the disallowed loss cannot be recovered through a higher basis in the replacement shares. The loss is permanently eliminated. IRS Publication 550 confirms this explicitly.
Is buying a call option on a stock a wash sale?
Potentially yes. IRC Section 1091 explicitly covers not just purchases but also contracts or options to acquire substantially identical stock or securities. Buying a call option on the same stock within the 61-day window can trigger the wash sale rule. The IRS has stated that entering into a contract to acquire stock within the wash sale window has the same effect as actually purchasing the stock. Short puts (where you are obligated to buy the stock if it falls to the strike price) are more ambiguous but raise similar concerns.
Can a wash sale carry over into the next tax year?
Yes. If you have an open wash sale at December 31 — meaning you sold at a loss and the replacement purchase was within the current year's lookback window — the disallowed loss is not claimed in the current year. It is deferred to the next year via the adjusted cost basis of the replacement. When you file Schedule D, you will see the adjustment on Form 1099-B from your brokerage. Cross-year wash sales are common for investors who harvest losses in late November and December.
Do wash sale rules apply to mutual fund distributions reinvested automatically?
Yes. Automatic dividend reinvestment can trigger a wash sale if you are simultaneously harvesting a loss on the same fund. If your mutual fund pays a distribution in December and automatically reinvests it by buying additional shares, and you sell shares of the same fund at a loss within 30 days of that reinvestment, the automatic purchase contaminates your harvest. To avoid this, suspend dividend reinvestment for funds you intend to harvest before you execute the sale.
Does the wash sale rule apply to bonds?
Yes. The wash sale rule applies to "stocks or securities," and bonds are classified as securities. However, because individual bonds are each uniquely identified by their CUSIP number, it is generally straightforward to avoid wash sales on bond harvesting — you simply purchase a different bond (different maturity, issuer, or CUSIP) as your replacement. Bond ETFs and bond funds raise the same substantially identical questions as equity funds: two funds with very similar duration, credit quality, and issuer composition could be considered substantially identical by the IRS.
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