What Happens to a Disallowed Wash Sale Loss? (w/Examples) + FAQs

This article reflects federal rules and general state rules as of June 2026 and covers tax years 2025 and 2026. Tax law changes — confirm current figures before you file. This guide is educational and is not a substitute for advice from a licensed CPA, enrolled agent, or tax attorney for your specific situation.

Quick Answer

A disallowed wash sale loss does not vanish. For tax years 2025 and 2026, the loss you cannot deduct now is added to the cost basis of the replacement shares and your old holding period carries over, so you recover it when you sell those shares. One exception: a loss disallowed because you rebought inside an IRA is gone forever.

Why Your “Lost” Loss Usually Comes Back

You sold a stock at a loss to cut your tax bill, but your broker stamped “wash sale loss disallowed” on your 1099-B, and now you are wondering if that money is gone. In most cases it is not gone — under Internal Revenue Code Section 1091, the disallowed loss is shifted onto the basis of the shares you bought back, so it is deferred, not destroyed. The painful part is timing: you lose the deduction this year, exactly when you wanted it, and you only get it back when you finally sell the replacement shares.

The stakes are real because wash sales are easy to trigger by accident, especially with automatic dividend reinvestment, recurring buys, and trades spread across multiple accounts. The IRS only allows individuals to deduct up to $3,000 of net capital losses against ordinary income per year (for both tax year 2025 and 2026, per IRS Topic No. 409), so a deferred loss can stall a tax plan you were counting on. Knowing where your loss goes — and the rare cases where it dies permanently — is the difference between a delay and a total write-off of your own money.

Here is what you will learn:

🧭 Where a disallowed loss actually goes and how to track it on your basis
💵 Worked dollar examples that show the exact math, step by step
⏳ How the wash sale clock and your transferred holding period really work
⚠️ The IRA and spouse-account traps that destroy a loss forever
🧾 How to report it on Form 8949 with Code W so the IRS sees it correctly

What a Wash Sale Is, in Plain English

A wash sale happens when you sell a stock or security at a loss and buy a “substantially identical” one within a 61-day window — 30 days before the sale, the day of the sale, or 30 days after. The rule lives in IRC Section 1091 and is explained for filers in IRS Publication 550. Its whole purpose is to stop you from claiming a tax loss while never really giving up your investment position.

The key word is loss. The wash sale rule only applies when you sell at a loss; selling at a gain is never a wash sale. The rule also only bites if you reacquire something substantially identical inside the window. If you sell at a loss and stay out for 31 days, or buy something genuinely different, there is no wash sale and your loss is fully deductible.

A common misconception is that the rule is about a single calendar month. It is not — it is a rolling 61-day period centered on each loss sale, and a purchase 30 days before the sale can trigger it just as easily as one after. The next step for any investor harvesting losses is simple: mark a calendar 31 days out from every loss sale and avoid buying back the same position until that date passes.

What “Substantially Identical” Means

The IRS has never published a hard definition of substantially identical, which is why this term causes so much confusion. Publication 550 and guidance like the Schwab wash-sale primer say you must use reasonable judgment. As a rule, the same company’s common stock is substantially identical to itself, and that includes shares, options to buy it, and contracts to acquire it.

Stocks of two different companies are normally not substantially identical, even in the same industry. So selling Coca-Cola and buying PepsiCo is generally fine, but selling and rebuying the same S&P 500 index fund is a wash sale. The consequence of guessing wrong is that the IRS disallows your loss on audit and may add interest. The safe move is to swap into a clearly different security — a different issuer or a fund that tracks a different index — if you want to stay invested.

What Actually Happens to the Disallowed Loss

When your loss is disallowed, two things happen at once, and both protect your money in the normal case. First, you cannot deduct the loss in the year of the sale. Second, the disallowed amount is added to the cost basis of the replacement shares you bought, per IRC Section 1091(d) and as confirmed in plain terms by the H&R Block wash sale guide. A higher basis means a smaller gain — or a bigger loss — when you eventually sell those replacement shares.

There is a second, easy-to-miss benefit: your holding period transfers too. The time you held the original shares is tacked onto the replacement shares. This matters because it can turn what would be a short-term gain into a long-term gain, which is taxed at lower rates. So the rule defers your loss but hands you a longer holding period as partial compensation.

The misconception here is that “disallowed” means “denied forever.” For ordinary taxable-account wash sales, that is false — the loss is deferred and recovered later. The action step is to record the new, higher basis and the transferred holding period in your records the moment a wash sale happens, because your broker tracks this only within a single account and may not catch trades spread across accounts.

A Fully Worked Example

Say you buy 100 shares of XYZ at $50, for a $5,000 cost. The price drops and you sell all 100 on March 1 at $40, for $4,000 — a $1,000 loss. On March 20, still inside the 30-day window, you buy 100 shares of XYZ back at $42, for $4,200.

That $1,000 loss is disallowed as a wash sale. It does not disappear: you add it to the $4,200 you paid, giving the new shares an adjusted basis of $5,200. Your holding period also includes the original holding time. If XYZ later climbs to $60 and you sell for $6,000, your taxable gain is only $800 ($6,000 minus $5,200), not the $1,800 you would have owed tax on without the basis bump — so the $1,000 came back to you.

The Trap: When a Disallowed Loss Is Gone Forever

The deferral promise breaks in a few specific situations, and these are the costliest. The most important is the IRA wash sale. If you sell a stock at a loss in your taxable account and buy the same stock in your IRA or Roth IRA within the 61-day window, Revenue Ruling 2008-5 says the loss is disallowed and your IRA basis is not increased. Because an IRA does not track basis for individual trades, the loss has nowhere to go — it is permanently lost.

This is uniquely harsh. In a normal wash sale you get the loss back later through basis; here you get nothing, ever. As the Bogleheads community summary of the ruling puts it, the loss is gone and you cannot recover it by adjusting the IRA trade. The action step is firm: never repurchase, in any IRA or Roth IRA, a security you just sold at a loss in a taxable account — wait at least 31 days, or buy a different security.

The Spouse and Controlled-Entity Trap

The wash sale rule also reaches across to your spouse and to entities you control. If you sell a stock at a loss and your spouse (or a corporation you control) buys a substantially identical security within the window, the loss is still disallowed under the IRS interpretation in Publication 550. The tax law treats a married couple’s economic position as one for this purpose.

The consequence depends on the account: if the replacement buy is in a regular taxable spouse account, the loss usually shifts to that account’s basis, but if the buy lands in a spouse’s IRA, you can hit the same permanent-loss problem as above. People often assume “different account, different person, no problem” — that assumption can cost the entire deduction. The fix is to coordinate trades across the whole household and treat all family accounts as one when harvesting losses.

Which Situation Applies to You?

The answer to “where did my loss go” depends on where you bought the replacement. Use this to find your case:

You rebought in the same taxable account: Your loss is deferred and added to the new shares’ basis. This is the normal, recoverable case.
You rebought in a different taxable account (yours or your spouse’s): Loss is still disallowed but generally shifts to the basis in that other taxable account. Track it yourself — the broker won’t.
You rebought inside any IRA or Roth IRA: Worst case. The loss is permanently disallowed under Revenue Ruling 2008-5 with no basis recovery.
You sold crypto at a loss and rebought it: As of 2026, Section 1091 does not apply to crypto, so the loss is generally allowed — but watch the economic substance doctrine (covered below).
You stayed out 31+ days, or bought a clearly different security: No wash sale. Your loss is fully deductible now.

How the 61-Day Window Works

The window is 61 days total: the 30 days before your loss sale, the sale day itself, and the 30 days after. A purchase anywhere in that span — even one made before you decided to sell — can trigger the rule. This is why automatic reinvestment and dollar-cost-averaging buys so often cause accidental wash sales, as flagged in the Fidelity wash-sale overview.

A frequent misconception is “30 days means a full month, so I’ll wait to the first of next month.” Calendar months vary in length, and counting must be by actual days, not months. To be safe, count 31 days from the trade date and only buy back after that day passes. Set a reminder, because a single early purchase can disallow the whole loss.

Crypto and the Wash Sale Rule in 2026

Cryptocurrency sits in a different bucket. Under IRS Notice 2014-21, the IRS treats crypto as property, not as “stock or securities.” Because Section 1091 specifically names stock and securities, the wash sale rule does not apply to direct crypto holdings as of tax year 2026, so an investor can sell Bitcoin at a loss and rebuy it immediately and still claim the loss.

That said, this is not a free pass. The IRS can still challenge a trade with no real economic purpose under the economic substance doctrine in IRC Section 7701(o). And the gap is widely expected to close — Congress has repeatedly proposed extending wash sale rules to digital assets. The practical step: if you harvest crypto losses, keep records showing a genuine change in market exposure or timing, and watch for new legislation before relying on the loophole next year.

Three Common Scenarios and Their Results

The first scenario is the everyday taxable rebuy, where the loss is simply deferred.

What You Did	What Happens to Your Loss
Sold 100 shares at a $1,000 loss, rebought the same stock 10 days later in the same brokerage account	Loss disallowed now, added to new shares’ basis; you recover it when you sell the replacement shares

The second scenario is the silent IRA trigger that destroys the loss.

What You Did	What Happens to Your Loss
Sold a stock at a $2,000 loss in your taxable account, bought the same stock in your Roth IRA 5 days later	Loss permanently disallowed under Revenue Ruling 2008-5; no basis increase, no future recovery

The third scenario is the accidental dividend-reinvestment wash sale.

What You Did	What Happens to Your Loss
Sold 200 shares of a fund at a loss, but the fund auto-reinvested a dividend into new shares 8 days earlier	A portion of the loss equal to the reinvested shares is disallowed and added to those shares’ basis

Three Named Examples

Maria, the RSU recipient. Maria sold 50 shares of her employer’s stock at an $800 loss in February 2026. She forgot that her vesting schedule released new RSU shares 12 days earlier. Because the vesting counts as acquiring identical stock inside the window, her $800 loss is disallowed and added to the basis of the vested shares — a scenario many employees discover only when they read Box 1g, as in this taxpayer’s 1099-B surprise.

David, the IRA mistake. David sold ABC stock at a $3,500 loss in his taxable account, then bought ABC in his traditional IRA a week later, thinking the accounts were separate. Under Revenue Ruling 2008-5, his $3,500 loss is permanently disallowed with no basis bump anywhere. He lost the entire deduction — about $770 in tax value at a 22% bracket.

Priya, the index-fund swapper. Priya sold an S&P 500 fund at a $4,000 loss in 2026 and immediately bought a total market fund tracking a different index. Because the two funds are not substantially identical, there is no wash sale and Priya keeps her full $4,000 loss while staying invested — the textbook legal harvest described by Investopedia’s legal wash sale guide.

How to Report a Disallowed Wash Sale Loss

You report wash sales on Form 8949, which flows into Schedule D. Your broker reports the disallowed amount in Box 1g (“Wash sale loss disallowed”) of your Form 1099-B. The figures must match what the IRS already has on file.

Follow these steps for each wash sale transaction:

List the sale on Form 8949, Part I for short-term holdings or Part II for long-term, with proceeds in column (d) and cost basis in column (e).
In column (f), enter code W to flag the transaction as a wash sale, per the IRS Form 8949 code table.
In column (g), enter the disallowed loss from Box 1g as a positive number, which reduces the loss you claim, as explained in this Code W reporting guide.
Add the disallowed amount to the cost basis of your replacement shares in your own records, and note the transferred holding period.
If you need step-by-step form help, see our internal guide How to Fill Out Form 8949 and the companion Schedule D Walkthrough.

The deadline is your normal return due date — April 15, 2026 for tax year 2025 (or October 15 with an extension). The cost is low if you do it yourself with the 1099-B in hand; expect roughly $150–$400 for a CPA if you have many trades or cross-account wash sales the broker did not catch.

Federal vs. State Treatment

The wash sale rule is federal, set by IRC Section 1091. Most states with an income tax start from your federal capital gain or loss numbers, so they automatically follow the same wash sale outcome — your deferred or disallowed loss carries through to the state return without a separate calculation.

The key difference is for no-income-tax states such as Florida, Texas, Washington, and Nevada. In those states there is no state-level capital gains tax at all for individuals, so the wash sale rule has no state consequence — it only affects your federal return. A common misconception is that you must do a separate state wash sale adjustment; in conforming states you do not, and in no-tax states there is nothing to adjust. Confirm your specific state’s conformity on your state Department of Revenue website before filing.

Treatment	Where It Applies
Follows federal wash sale result automatically	Most income-tax states that start from federal AGI or capital gains
No state effect at all	No-income-tax states (e.g., Florida, Texas, Washington, Nevada)

Mistakes to Avoid

These errors turn a recoverable loss into a lost or misreported one:

Rebuying in an IRA after a taxable loss sale. The loss is permanently destroyed under Revenue Ruling 2008-5 with no basis recovery.
Ignoring your spouse’s trades. A spouse buying the same security disallows your loss, often without you realizing it.
Forgetting dividend reinvestment. Auto-reinvested shares inside the window trigger partial wash sales and shrink your deduction.
Counting 30 days as one calendar month. You must count actual days; an early rebuy disallows the whole loss.
Assuming separate brokers are safe. Cross-account wash sales are not always caught on the 1099-B, leaving you to track them, as warned in this multi-account wash sale guide.
Not adjusting basis on replacement shares. Skipping this means you pay tax twice on the same money when you sell.
Treating two index funds tracking the same index as different. They are substantially identical and trigger a wash sale.
Selling at year-end and rebuying in early January. The window crosses the new year, so the loss is still disallowed.

Do’s and Don’ts

Do:

Wait 31 days before rebuying the same security, because that fully clears the window.
Swap into a non-identical security to stay invested, since a different issuer or index avoids the rule.
Track basis and holding period on replacement shares, because that is how you recover the loss later.
Coordinate household accounts, because spouse and IRA buys count against you.
Reconcile your 1099-B Box 1g with your own records, since brokers miss cross-account triggers.

Don’t:

Don’t rebuy in an IRA after a taxable loss, because the deduction dies permanently.
Don’t rely on calendar months, since the rule counts exact days.
Don’t ignore options and contracts, because acquiring an option to buy the stock also triggers the rule.
Don’t assume crypto rules will stay, since Congress may extend wash sales to digital assets soon.
Don’t skip Code W on Form 8949, because a mismatch with the 1099-B invites an IRS notice.

Pros and Cons of How the Rule Works

Pros for the taxpayer:

The loss is usually preserved, because basis adjustment defers rather than destroys it.
Your holding period transfers, which can convert a short-term gain into lower-taxed long-term gain.
You can stay invested, since buying a non-identical security keeps market exposure while harvesting the loss.
Brokers report Box 1g for you, which simplifies same-account reporting.
Gains are never affected, so the rule only ever touches loss sales.

Cons for the taxpayer:

Timing is lost, because you forfeit the deduction in the year you wanted it.
IRA rebuys destroy the loss, with no recovery mechanism at all.
Cross-account tracking is on you, since brokers don’t combine accounts.
“Substantially identical” is vague, leaving room for IRS disputes.
Accidental triggers are common, from dividends, RSUs, and recurring buys.

What to Do Next

Take these steps in order once you spot a disallowed wash sale:

Pull every Form 1099-B and check Box 1g for disallowed amounts across all your accounts.
Identify where each replacement purchase landed — taxable account, spouse account, or IRA — to learn whether the loss is deferred or permanent.
Add each disallowed amount to the basis of the matching replacement shares and record the transferred holding period in writing.
Report each wash sale on Form 8949 with Code W and carry the totals to Schedule D before the April 15, 2026 deadline.
Call a CPA or enrolled agent if you have cross-account or IRA wash sales, large dollar amounts, or trader-status questions, since these are where costly permanent losses hide.

FAQs

Does a disallowed wash sale loss disappear? No. In a normal taxable account the loss is deferred — it is added to the basis of your replacement shares and recovered when you sell them. Only IRA-triggered wash sales destroy the loss permanently.

Where does the disallowed loss go? Onto the cost basis of your replacement shares. Under Section 1091(d), the disallowed amount raises your basis, lowering future gain or increasing future loss when you sell those shares.

Can I ever deduct a wash sale loss? Yes, usually later. You recover it when you sell the replacement shares, because the added basis reduces your taxable gain at that time. The IRA exception is the main case where you never can.

What happens if I rebuy inside my IRA? The loss is permanently lost. Revenue Ruling 2008-5 disallows the loss and bars any basis increase in the IRA, so there is no future recovery — the entire deduction is gone.

How long must I wait to avoid a wash sale? 31 days. Buying substantially identical securities within 30 days before or after the loss sale triggers the rule, so waiting a full 31 days after the sale clears the window.

Does the wash sale rule apply to crypto in 2026? No, not directly. The IRS treats crypto as property, not securities, so Section 1091 does not apply as of 2026. The economic substance doctrine can still challenge purely tax-motivated trades.

Does selling at a gain ever trigger a wash sale? No. The rule applies only to loss sales. If you sell at a gain, there is no wash sale no matter how quickly you rebuy.

Are two different companies’ stocks substantially identical? No, generally. Stocks of different companies are usually not substantially identical, so selling one and buying a competitor avoids the rule. Two funds tracking the same index, however, are identical.

Does my spouse’s purchase count against me? Yes. If your spouse buys a substantially identical security within the window, your loss is disallowed because the IRS treats the married couple as one economic unit.

How do I report it on my tax return? On Form 8949 with code W. Enter the disallowed loss from Box 1g of your 1099-B as a positive number in column (g), then carry the totals to Schedule D.

Will my state also disallow the loss? Usually yes. Most income-tax states start from your federal numbers, so the disallowance carries through. No-income-tax states like Florida and Texas have no state effect at all.

Does the holding period transfer to the new shares? Yes. The time you held the original shares is added to the replacement shares, which can turn a short-term position into a lower-taxed long-term one.

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