Can a Wash Sale Raise Your Tax Bill? (w/Examples) + FAQs

This article reflects federal rules (IRC §1091) and general state conformity as of June 2026 and covers tax year 2025 (the 2026 filing season). Tax law changes — confirm current figures before you file. This is educational information, not personal tax advice; for your specific situation, see a licensed CPA or tax attorney.

Quick Answer

Yes — a wash sale can raise your tax bill for the year. When you sell at a loss and rebuy a substantially identical security within 30 days, the IRS disallows that loss for now under IRC Section 1091. You lose the deduction you expected, so your taxable income — and your tax — goes up.

Most investors think a loss is always a loss they can write off. But if you buy the same stock, ETF, or fund back too soon, the tax break you counted on vanishes from this year’s return, and you owe more than you planned. In some cases — like rebuying inside an IRA — that loss is gone for good.

The timing matters because the wash sale window is wider than people expect: it covers 30 days before and 30 days after the sale, a 61-day trap. Active traders, year-end tax-loss harvesters, and anyone with automatic dividend reinvestment turned on are most at risk. Tax-loss harvesting is big business — in 2025, Parametric harvested over $8.8 billion in losses for clients, with a potential tax benefit topping $3.3 billion. A single wash sale slip can wipe out that benefit for you.

Here is what you will learn:

📉 How a disallowed loss directly raises the tax you owe this year, with the exact math.
🔒 Why a wash sale inside an IRA destroys your loss permanently — not just for one year.
🗓️ How the 61-day window works and the three ways people trip it without knowing.
🪙 Whether the rule hits crypto in 2025 and 2026 — and how that is changing.
🧾 How to report a wash sale on Form 8949 with Code W, step by step, so the IRS math is right.

What a Wash Sale Actually Is

A wash sale happens when you sell a stock or security at a loss and buy a “substantially identical” one within a set window around that sale. The rule lives in IRC Section 1091 and is explained for filers in IRS Publication 550. Its purpose is to stop you from claiming a tax loss while never really giving up your investment position.

The window is 61 days long. It covers the 30 days before you sell, the day of the sale, and the 30 days after you sell, as Form 8949 guidance confirms. Many people assume the clock only runs forward from the sale. It runs both ways, which is why a buy you made before the loss sale can still trigger the rule.

When a wash sale triggers, the IRS does not let you deduct the loss in the current year. Instead, the disallowed loss is added to the cost basis of the replacement shares you bought, and the holding period of the old shares carries over too. The consequence is a higher taxable income now and a deferred (not destroyed) loss later — unless the replacement shares sit in an IRA, where the loss disappears for good.

A common misconception is that a wash sale is illegal or triggers a penalty. It is neither. It is a timing rule, and the only “punishment” is losing the deduction this year. What you should do about it: track every buy and sell of the same security across a 61-day window, and if you want to keep the loss, wait at least 31 days before rebuying the identical security.

What Counts as “Substantially Identical”

The tax law never defines “substantially identical,” which is exactly why investors get tripped up. Selling and rebuying the same security clearly counts, as Fidelity explains for ETFs. The same ticker bought back in any of your accounts — even a different broker — meets the definition.

The consequence of guessing wrong is a denied loss you thought was safe. Two S&P 500 funds tracking the same index are a danger zone; VOO and VOO futures are treated as identical, while VOO and SPY are generally viewed as not identical because they are different funds from different issuers. Stocks of two different companies are not identical, even in the same industry.

What you should do: to harvest a loss and stay invested, swap into a similar but not identical holding. Fidelity’s example is selling a single drug stock and buying a pharmaceutical-sector ETF instead — close exposure, but not substantially identical, so the loss survives.

How a Wash Sale Raises Your Tax Bill

The increase is simple in concept: a loss you planned to deduct gets removed from this year’s return, so your taxable income rises by that amount. If you are in the 24% federal bracket and a $5,000 loss is disallowed, you lose a deduction worth about $1,200 in tax savings this year. The money is not a fine — it is the tax break you expected but no longer get.

There are four distinct ways a wash sale costs you more. First, a disallowed loss can no longer offset capital gains you realized, so those gains stay fully taxable. Second, it can no longer offset up to $3,000 of ordinary income for the year. Third, if the rebuy lands in an IRA, the loss is permanently disallowed and never comes back. Fourth, a year-straddling wash sale can push the deduction into a later tax year when you may get less value from it.

The key nuance most people miss: in a normal taxable-account wash sale, the loss is only deferred, not lost. The disallowed amount is added to your replacement shares’ basis, so you recover it when you finally sell those shares for good, as Form8949.com explains. The real permanent damage happens with IRAs, which the next section covers.

The Disallowed-Loss-to-Basis Mechanic

When the loss is disallowed, it is not deleted — it is added to the cost basis of the replacement shares, per IRS Form 8949 rules. A higher basis means a smaller taxable gain (or a bigger loss) when you eventually sell those replacement shares. The holding period of the original shares also tacks on.

The consequence is that you keep the tax benefit eventually, but not this year — a cash-flow and timing hit, not a total loss. If you sold at a $2,000 loss and rebought, your new shares carry an extra $2,000 of basis. When you sell them later with no wash sale, that $2,000 finally reduces your taxable gain.

What you should do: keep careful records of the adjusted basis your broker reports in Box 1e of your 1099-B, which already folds in deferred wash-sale losses, as noted by Form8949.com. If you change brokers, the new broker may not know the adjusted basis, so save your statements.

A Fully Worked Example (Copy the Math)

Here is the exact math so you can follow it dollar for dollar. Assume tax year 2025, the 24% federal bracket, and no other capital gains.

Step 1: On November 3, 2025, you buy 100 shares of Stock XYZ at $50 each, for a $5,000 cost. Step 2: On December 10, 2025, the price drops to $35, and you sell all 100 shares for $3,500, locking in a $1,500 loss. Step 3: On December 22, 2025 — only 12 days later — you buy 100 shares of XYZ again at $36, for $3,600.

Because you rebought within 30 days, the $1,500 loss is a wash sale and is disallowed for 2025. You expected the $1,500 loss to cut your taxable income, saving roughly $360 in tax (24% × $1,500). Instead, that $360 of savings disappears from your 2025 return, so your tax bill is $360 higher than you planned.

The $1,500 is not gone, though. It is added to your replacement shares’ basis: your new 100 shares cost $3,600 but get an adjusted basis of $5,100 ($3,600 + $1,500). When you later sell those shares with no rebuy, the extra $1,500 of basis reduces your future taxable gain — so in a taxable account, the benefit is deferred, not destroyed.

The IRA Trap: When the Loss Is Gone Forever

The single most damaging wash sale is one where you sell at a loss in a taxable account and buy the same security inside your IRA within the window. Here, the loss is not just deferred — it is permanently disallowed. The IRS confirmed this in Revenue Ruling 2008-5.

The reason is brutal in its logic. Normally the disallowed loss attaches to the replacement shares’ basis. But an IRA does not recognize capital gains or losses, so that basis adjustment has no effect, as multiple advisors confirm. The Bogleheads community summarizes the outcome bluntly: “the loss is gone” and you can never recover it.

The consequence is total: a $3,500 taxable-account loss rebought in your IRA vanishes from every tax year, forever. J.P. Morgan warns that “the loss would be lost completely, because the position in the IRA has no basis.” This even includes a Roth IRA.

A common misconception is that the wash sale rule does not apply across different account types. It absolutely does — the rule reaches into your IRA, your spouse’s accounts, and accounts at other brokers. What you should do: never buy a security in any IRA within 30 days of selling that same security at a loss in a taxable account. Turn off automatic investing in your IRA if you are harvesting losses elsewhere.

Which Situation Applies to You?

The answer depends on where you rebought and what you bought. Use this to find your case.

You rebought the identical security in the same taxable brokerage account: Your loss is deferred and added to the new shares’ basis. You recover it later. Jump to the worked example above.
You rebought the identical security inside an IRA or Roth IRA: Your loss is permanently disallowed. This is the worst case. See the IRA Trap section.
You sold crypto at a loss and rebought it immediately: For tax year 2025, the wash sale rule does not apply to crypto. See the crypto section below.
You bought a similar-but-not-identical fund (different issuer/index): No wash sale, loss is fully deductible now. This is the safe harvesting move.
Your dividend reinvestment bought shares within 30 days of a loss sale: A partial wash sale applies to the reinvested shares. See Mistakes to Avoid.

Crypto and the Wash Sale Rule (2025 vs. 2026)

For tax year 2025, the wash sale rule does not apply to cryptocurrency. Because the IRS treats crypto as property — not “stock or securities” — Section 1091 does not reach it, as a CPA analysis confirms. You can sell Bitcoin at a loss and rebuy it the next day and still deduct the loss.

This is a genuine, current advantage for crypto investors, and TurboTax confirms that “the wash-sale rule typically doesn’t apply to crypto”. The exception is crypto held through stock-like products — for example, a crypto ETF that is itself a security can fall under the rule.

This area is unsettled and changing, so watch it closely. Lawmakers have repeatedly proposed extending wash sale treatment to digital assets, and tax-software providers are already preparing for a future where the 30-day window applies to crypto. As of June 2026, no federal statute has imposed wash sale treatment on ordinary crypto. What you should do: if you harvest crypto losses, do it under 2025 rules while they last, and confirm the law before you file, because Congress could change it.

Three Common Scenarios

These are the three most frequent ways a wash sale plays out.

Trader Move	Tax Result
Sell a stock at a loss, rebuy the same ticker in 10 days in a taxable account	Loss disallowed this year, added to new shares’ basis, recovered when you finally sell
Sell a stock at a loss in taxable, rebuy the same ticker in your IRA within 30 days	Loss permanently disallowed — never recoverable in any year
Sell a stock at a loss, buy a different-issuer sector ETF instead within 30 days	No wash sale — loss is fully deductible now

A second table shows how timing changes the outcome.

Rebuy Timing	What Happens to Your Loss
Rebuy identical security on day 31 or later	Loss is allowed in full — no wash sale
Rebuy identical security on day 1–30 after the sale	Loss disallowed (deferred or permanent)
Bought identical security 1–30 days before the loss sale	Loss still disallowed — the window runs backward too

A third table separates the asset types.

Asset Sold and Rebought	2025 Wash Sale Treatment
Stocks, ETFs, mutual funds, options	Wash sale rule applies — loss disallowed if rebought in window
Cryptocurrency (direct holdings)	Rule does not apply — loss deductible even if rebought next day
Crypto held as a security/ETP	Rule can apply — treated like a security

Three Named Examples

Maria, the active trader. Maria sells 200 shares of TechCo at a $4,000 loss on December 5, 2025, then rebuys 200 shares on December 18 because the price looked cheap. The wash sale disallows her $4,000 loss for 2025. She expected to offset $4,000 of gains; instead those gains stay taxable, raising her 2025 tax by about $960 at a 24% rate. The loss attaches to her new shares’ basis, so she recovers it only when she sells them later.

David, the IRA mistake. David sells a mutual fund at a $3,500 loss in his taxable account on November 20, 2025. Two weeks later, his IRA’s automatic monthly investment buys the same fund. Per Revenue Ruling 2008-5, his $3,500 loss is permanently disallowed — it never reduces his taxes in any year. A single automatic purchase cost him the entire deduction.

Priya, the smart harvester. Priya sells an S&P 500 mutual fund at a $6,000 loss on December 10, 2025, and immediately buys a total-market ETF from a different issuer. Because the two are not substantially identical, there is no wash sale. She keeps her market exposure, claims the full $6,000 loss for 2025, and offsets her capital gains — saving about $1,440 at a 24% rate.

How to Report a Wash Sale on Form 8949

A disallowed wash sale is reported on Form 8949 using Code W, which flows into Schedule D. Your broker flags it for you with an amount in Box 1g, “Wash sale loss disallowed,” on your 1099-B. (For a full walkthrough, see our How to Fill Out Form 8949 guide and our Schedule D guide.)

Step 1: Report the sale on Form 8949 with the proceeds and original cost basis as normal. Step 2: In column (f), enter the code “W” to mark the transaction as a wash sale. Step 3: In column (g), enter the disallowed loss amount from Box 1g of your 1099-B as a positive number, which reduces the loss you can claim.

The consequence of skipping this is an inaccurate return. If you ignore the broker’s Box 1g flag and claim the full loss, you understate your income, and the IRS — which receives a matching copy of your 1099-B — can send a notice (a CP2000) proposing more tax plus interest. What you should do: match every Code W and Box 1g amount on your return to your 1099-B, and keep the statement showing your adjusted basis in Box 1e for the replacement shares.

Mistakes to Avoid

Forgetting dividend reinvestment (DRIP). Auto-reinvested dividends within 30 days of a loss sale create a partial wash sale, disallowing part of your loss. Turn off DRIP before harvesting.
Rebuying in your IRA or Roth IRA. This permanently destroys the loss, the single costliest error, per IRS Revenue Ruling 2008-5.
Ignoring the 30 days before the sale. A purchase you made earlier can still trigger the rule; the window runs both directions, covering 61 total days.
Assuming different accounts are safe. The rule applies across all your accounts and your spouse’s accounts; using a second broker does not avoid it.
Buying back on day 30 instead of day 31. Day 30 is still inside the window, so the loss is disallowed. You must wait the full 31 days.
Treating two index funds as different. Two funds tracking the same index can be substantially identical, voiding the loss; only different-issuer or different-index swaps are clearly safe.
Overlooking options and contracts. Buying a call option on the same security within the window also triggers the rule, not just buying shares.
Not adjusting your records after a broker switch. A new broker may not carry your deferred wash-sale basis, so you must track it yourself or risk overpaying later.

Do’s and Don’ts

Do’s

Do wait at least 31 days to rebuy an identical security, because that fully clears the 61-day window and preserves your loss.
Do swap into a similar-but-not-identical fund if you want to stay invested, since that keeps exposure without triggering the rule.
Do turn off automatic dividend reinvestment during harvesting, because a single auto-buy can disallow part of your loss.
Do check every account, including IRAs and a spouse’s, because the rule reaches across all of them.
Do reconcile Box 1g of your 1099-B to your return, because the IRS gets a matching copy and flags mismatches.

Don’ts

Don’t rebuy the loss security in any IRA, because the loss becomes permanently unrecoverable.
Don’t assume crypto is risky in 2025, because the rule does not apply to direct crypto holdings this year.
Don’t rely on a different broker to dodge the rule, because the rule is per-taxpayer, not per-account.
Don’t ignore options and short sales, because contracts on the same security also trigger the rule.
Don’t forget the loss is usually only deferred, because in a taxable account you recover it through the basis adjustment.

Pros and Cons of the Wash Sale Rule

Pros

It only defers most losses, so in a taxable account you eventually recover the deduction through a higher basis.
It is a timing rule, not a penalty, meaning there is no fine — just a delay in claiming the loss.
It is easy to avoid, because simply waiting 31 days or swapping funds keeps your loss intact.
Brokers track it for you via Box 1g, reducing the chance of an error on simple cases.
It does not touch direct crypto in 2025, giving digital-asset investors more harvesting flexibility this year.

Cons

It can permanently destroy IRA-related losses, the harshest outcome with no recovery.
The 61-day window is wider than people expect, catching trades made before the sale.
It can raise your current-year tax by removing a deduction you counted on.
“Substantially identical” is undefined, leaving gray areas that create risk.
Cross-account reach is easy to miss, especially with automatic investing or a spouse’s trades.

What to Do Next

Map your 61-day windows now. List every loss sale and check for any purchase of the same security 30 days before or after — in every account, including IRAs and your spouse’s.
Turn off automatic investing and DRIP in accounts holding securities you plan to sell at a loss this year.
If you want to harvest, swap into a different-issuer fund with similar exposure, or wait the full 31 days before rebuying.
Gather your 1099-B and check Box 1g (disallowed loss) and Box 1e (adjusted basis) before filing.
Report disallowed losses on Form 8949 with Code W and a positive column (g) adjustment, flowing to Schedule D.
Call a professional if you have IRA wash sales, large harvested losses, options, multiple brokers, or a state that diverges — a CPA visit typically runs a few hundred dollars and can save far more.

Federal vs. State Treatment

Federal law under IRC §1091 sets the wash sale rule, and it applies on your federal return for tax year 2025. The disallowed loss raises your federal taxable income for the year it is denied.

Most states that tax capital gains start from your federal taxable income or federal capital gain figure, so they automatically pick up the wash sale adjustment — meaning the disallowed loss raises your state tax too. States with no income tax, such as Florida, Texas, Washington, Nevada, South Dakota, Wyoming, Alaska, Tennessee, and New Hampshire (on wages), do not tax this gain at all, so the wash sale has no state effect there.

Because state conformity to federal rules varies and some states have their own adjustments, never assume your state matches federal treatment exactly. What you should do: check your state’s capital gains rules on your state Department of Revenue’s specific page, and if your state diverges or you live in a high-tax state like California, confirm the treatment with a local CPA.

FAQs

Can a wash sale raise my taxes? Yes. A disallowed loss is removed from your current-year return, so your taxable income rises. In a taxable account the loss is deferred to the replacement shares’ basis; in an IRA it is lost forever.

How long is the wash sale window? 61 days. It covers 30 days before the sale, the sale day, and 30 days after. A purchase in any part of that window can trigger the rule, even one made before you sold.

Is a wash sale illegal? No. It is a tax timing rule, not a crime, and there is no penalty. You simply cannot deduct the loss in the current year if you rebuy a substantially identical security in the window.

Do I lose the wash sale loss forever? Usually no. In a taxable account, the loss is added to your replacement shares’ basis and recovered when you sell them. The exception is an IRA repurchase, where the loss is permanently disallowed.

Does the wash sale rule apply to crypto in 2025? No. For tax year 2025, the IRS treats crypto as property, not securities, so Section 1091 does not apply. You can sell and rebuy crypto and still claim the loss.

Will crypto wash sale rules change? Possibly. Congress has repeatedly proposed extending wash sale rules to digital assets. As of June 2026, no statute does so for direct crypto, but this is unsettled — confirm the current law before filing.

Does the rule apply across different brokerage accounts? Yes. The rule is per taxpayer, not per account. It reaches purchases in all your accounts, your IRAs, and your spouse’s accounts, so a second broker does not help you avoid it.

What is “substantially identical”? The same or nearly the same security. The same ticker clearly qualifies. Two funds tracking the same index can qualify; a different-issuer fund or a sector ETF instead of a single stock generally does not.

How do I report a wash sale on my tax return? Form 8949 with Code W. Enter “W” in column (f) and the disallowed amount from Box 1g of your 1099-B as a positive number in column (g). The total flows to Schedule D.

How do I avoid a wash sale? Wait 31 days or swap funds. Either wait at least 31 days before rebuying the identical security, or buy a similar-but-not-identical fund right away to keep your loss and your market exposure.

Does the wash sale rule apply to gains? No. It only disallows losses. If you sell at a gain, the gain is fully taxable and the wash sale rule has no effect on it.

Do dividend reinvestments trigger wash sales? Yes. Auto-reinvested dividends that buy the same security within the 61-day window create a partial wash sale, disallowing the loss tied to those reinvested shares.

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