Wash Sale Tax Rule: The 61-Day Window, IRAs, and Form 8949

The wash sale rule disallows your tax loss when you sell a stock or security at a loss and buy the same or a substantially identical investment within 30 days before or after the sale. The disallowed loss usually isn’t gone for good. Under 26 U.S.C. § 1091, it gets folded into the cost basis of the replacement shares, so the tax benefit shifts to whenever you eventually sell those.¹ The rule exists to stop investors from claiming paper losses while effectively holding the same position, and it’s the most common way tax-loss harvesting goes wrong.

The 61-Day Window

The window covers 30 days before the sale, the sale date itself, and 30 days after. Any purchase of a substantially identical security inside that stretch triggers the disallowance. The pre-sale portion catches an obvious workaround: buying the replacement first, waiting a few days, then dumping the original at a loss. Congress closed that door in the statute.

Two details save people from unnecessary worry. The rule applies only to losses; a gain plus an immediate repurchase is fine. And the one statutory carve-out is for securities dealers taking losses in the ordinary course of business. Short sales are covered too. Closing a short at a loss and then opening another short on the same security, or selling substantially identical stock, within the window triggers the same treatment.¹

What Counts as Substantially Identical

The IRS has deliberately kept this fuzzy. Publication 550 tells taxpayers to weigh “all the facts and circumstances,” which gives the agency room to challenge trades that walk and talk like wash sales even when they look different on paper.² A few points are settled:

Selling shares of a company and buying shares of the same company is the textbook case.
Options and contracts to buy or sell a stock count as the stock itself. Selling shares at a loss and then buying a call on the same stock within 30 days triggers the rule.¹
Stock in one company is ordinarily not substantially identical to stock in another, even in the same industry. Selling one bank stock and buying a different bank stock the same day generally doesn’t trigger the rule.²
Convertible preferred stock can be treated as substantially identical to the common stock it converts into when the ratio is close to market.²

ETFs and mutual funds are the gray zone. The IRS has never issued a definitive ruling. Two index funds that track the same benchmark and hold nearly identical portfolios carry real risk. Funds tracking meaningfully different indexes are generally treated as safe, though no published threshold exists. When in doubt, buy something that tracks a noticeably different index or holds a different mix of securities.

What Happens to the Disallowed Loss

Section 1091(d) sets the new basis of the replacement shares as the basis of the shares you sold, adjusted by the difference between what you paid for the replacements and what you got for the originals.¹ In everyday terms, the disallowed loss gets added to the price of your replacement shares.

Numbers make it clearer. You buy a stock for $50, sell it for $40 for a $10 loss, and buy it back within the window for $42. The $10 loss is disallowed. Your new basis isn’t $42; it’s $52, the $42 purchase price plus the $10 disallowed loss.³ When you sell the replacement shares later, the higher basis reduces the taxable gain or increases the deductible loss.

Your holding period carries over too. The time you held the original shares tacks onto the replacement shares.⁴ Ten months on the original plus three months on the replacement gets you to thirteen months, which can push a short-term gain into the long-term rate bracket.

Wash Sales Across Accounts, Spouses, and IRAs

The rule follows the taxpayer, not the account. Selling in one brokerage and buying in another within the window still triggers it, and neither broker will see the full picture. Reconciling cross-account wash sales is your responsibility.

Spousal purchases carry risk. The IRS has taken the position that a substantially identical purchase by your spouse inside the window can disallow your loss. Tax professionals debate the exact statutory footing, but the agency’s stance is clear enough that most people shouldn’t ignore it.

The IRA Trap

The retirement-account version is the one to watch. Sell a stock at a loss in a taxable brokerage account, then buy the same stock inside a traditional or Roth IRA within 30 days, and the loss is disallowed under the normal rule. In a taxable account, that disallowed loss at least gets added to the basis of the replacement shares. In an IRA, there is no basis adjustment mechanism to catch it. The loss simply vanishes. Revenue Ruling 2008-5 confirmed this outcome for both traditional and Roth IRAs.⁵⁶

Automatic dividend reinvestment in an IRA is the usual culprit. A small reinvested dividend on shares you also hold in the IRA can quietly disallow a much larger loss you harvested in a taxable account. Before selling for a loss, check whether any retirement account holds the same security and has automatic purchases scheduled inside the 61-day window.

How to Harvest Losses Without Triggering the Rule

Loss harvesting still works. You just need to be deliberate about what happens in the 61-day window around each sale.

Wait 31 days before buying back the same security. Simple, but you’re exposed to a rebound while you’re out.
Buy a fund that isn’t substantially identical. Sell an S&P 500 index fund and buy a total market fund, or swap one sector ETF for another that tracks a different index. The wider the difference in holdings and methodology, the safer.
Replace an individual stock with a diversified sector or industry ETF. A single stock and a broad fund covering that industry are generally not substantially identical.²
Turn off dividend reinvestment and any automatic contributions for the security you’re selling, in every account you hold.

Partial repurchases only partially disallow the loss. Sell 500 shares at a loss and buy back 200 within the window, and only the loss on 200 shares is disallowed. Publication 550 matches replacement shares with sold shares in the order they were acquired.² That matters when you’re gradually scaling out of a position.

Cryptocurrency

The wash sale rule does not currently apply to direct holdings of cryptocurrency. Section 1091 covers “stock or securities,” and the IRS treats crypto as property.¹ Selling Bitcoin at a loss and buying it back the same day does not trigger the rule.

Congress has considered closing this gap several times, including in the Build Back Better Act, but no such change has been signed into law. Some online sources incorrectly claim the Infrastructure Investment and Jobs Act of 2021 extended the wash sale rule to crypto starting in 2026; that law addressed broker reporting for digital assets, not wash sale treatment.

One boundary matters here: a Bitcoin ETF or similar exchange-traded product is a security, and it is subject to the normal wash sale rule. Selling a crypto ETF at a loss and buying it back within 30 days triggers a wash sale. The exemption covers direct spot holdings, not securities that track crypto prices.

Reporting on Form 8949

Wash sales get reported on Form 8949, which flows into Schedule D of Form 1040.⁷ For each wash sale, enter code “W” in column (f) and put the disallowed loss as a positive number in column (g).⁸ The positive adjustment cancels out the loss you reported so you aren’t deducting the disallowed portion.

Your broker will flag wash sales on Form 1099-B, but only for trades within that single firm. Cross-broker wash sales, IRA purchases, and some option and dividend-reinvestment situations get missed. The IRS still holds you responsible for the ones the broker didn’t catch, so multi-account traders need to reconcile the 1099-Bs manually or use software built for the job.

An Exit for Qualifying Active Traders

Section 475(f) lets a person engaged in a trade or business as a trader in securities elect mark-to-market accounting.⁹ Under the election, positions are treated as sold at fair market value on the last business day of the year, all gains and losses become ordinary, and the wash sale rule stops applying.

The trade-offs are real. You lose long-term capital gains rates on trading positions, you owe tax on unrealized gains at year-end, and the election is essentially permanent without IRS consent to revoke. It also has a firm deadline: the election statement must be filed with your prior-year tax return by the original due date, no extensions. Qualifying as a trader rather than an investor is a high bar based on trading frequency, average holding period, hours spent, and reliance on trading as an income source. Occasional day trading or a busy swing-trading stretch won’t clear it, and claiming trader status incorrectly can cost you the deductions plus penalties.

1
Office of the Law Revision Counsel. 26 U.S. Code 1091 – Loss From Wash Sales of Stock or Securities
2
Internal Revenue Service. Publication 550 (2025), Investment Income and Expenses
3
Internal Revenue Service. Income – Capital Gain or Loss Workout
4
Office of the Law Revision Counsel. 26 U.S. Code 1223 – Holding Period of Property
5
Internal Revenue Service. Revenue Ruling 2008-5
6
Internal Revenue Service. Internal Revenue Bulletin: 2008-3
7
Internal Revenue Service. Instructions for Form 8949 (2025)
8
Internal Revenue Service. Form 8949 Codes
9
Office of the Law Revision Counsel. 26 U.S. Code 475 – Mark to Market Accounting Method for Dealers in Securities