How Do You Fix a Wash Sale Your Broker Missed? (w/Examples) + FAQs

This article reflects federal IRS rules as of June 2026 and covers tax year 2025 (the 2026 filing season). It also notes state treatment in general terms. Tax law changes — confirm current figures with IRS.gov before you file.

Quick Answer

You fix a broker-missed wash sale by reporting the trade yourself on Form 8949, entering code “W” in column (f) and the disallowed loss as a positive number in column (g). This adds the loss back, then rolls it into the cost basis of the replacement shares. For tax year 2025, file Form 8949 with Schedule D.

A wash sale your broker missed is not an error you caused — it is a gap in what brokers are required to track. A broker only watches for wash sales inside one account, holding the same CUSIP, at that one firm. The moment your replacement shares land in a different account, an IRA, a spouse’s account, or show up as a “substantially identical” fund or option, the broker’s software goes blind. The loss is still disallowed under Section 1091, and the duty to report it shifts to you.

The stakes are real and time-sensitive. The IRS receives a copy of every Form 1099-B, so if your return claims a loss the rules disallow, the matching system can flag it, recompute your tax, and send a CP2000 notice with interest. Whether you are filing on a deadline this spring or you already filed and just realized the mistake, the fix is the same set of steps — done now on a fresh return, or later on an amended one.

🧩 What a “missed” wash sale is and the five blind spots that cause brokers to skip it.
🛠️ The exact Form 8949 columns, codes, and math to correct it yourself, step by step.
💵 Three fully worked dollar examples you can copy for your own numbers.
⏰ How to amend a return you already filed, the deadline, and what it costs.
🚫 Seven mistakes that turn a small fix into an audit headache — and how to dodge each.

What a “Wash Sale” Actually Is

A wash sale is a tax rule that stops you from claiming a loss on paper while you stay invested in the same thing. Under IRC Section 1091, the loss is disallowed if, within 30 days before or after the sale, you buy “substantially identical” stock or securities. The window is 61 days total — 30 days on each side, plus the day of the sale.

The loss is not gone forever. It is deferred. You add the disallowed loss to the cost basis of the replacement shares, as IRS Publication 550 explains. When you later sell those replacement shares (outside a new wash window), you finally get the benefit. Your holding period also carries over, so the old waiting time toward long-term status counts.

Here is why the rule exists: without it, you could sell a stock at a $5,000 loss on December 31, buy it right back on January 2, claim the loss against your income, and never actually change your investment. Congress closed that door in 1921. The consequence of ignoring it today is that the IRS recomputes the loss, raises your tax, and adds interest from the original due date — so a $5,000 “loss” you wrongly claimed can cost you real money plus a penalty if it looks careless.

The common misconception is that a wash sale is a penalty or that the money vanishes. It is neither. It is a timing rule. What you should do about it: keep the disallowed amount tied to the replacement lot in your own records, because that is the basis you will use when those shares finally sell.

Why Brokers Miss Wash Sales (The Five Blind Spots)

Brokers are required to report wash sales only in narrow conditions, set by the cost-basis rules in Section 6045. They must flag a wash sale when the loss sale and the replacement buy involve the same security (identical CUSIP), in the same account, at the same firm. Step outside any one of those three boxes and the broker has no legal duty — and usually no ability — to catch it.

That single-account, same-CUSIP limit is the root of every “missed” wash sale. The broker is not making a mistake; it simply cannot see the rest of your financial life. You are the only person who sees all of your accounts at once, which is exactly why the IRS puts the reporting duty on you.

Blind Spot 1: Two Different Brokers

If you sell a stock at a loss in your Schwab account and buy it back within 30 days in your Fidelity account, neither broker sees the other. According to TaxSlayer’s guidance, these “won’t have a wash sale indicated on Form 1099-B, but they are wash sales nonetheless.” The consequence: both 1099-Bs show a clean loss, your return claims it, and the IRS later disallows it. What to do: pull every 1099-B together and scan for the same ticker bought within 30 days across firms.

Blind Spot 2: A Taxable Sale Paired With an IRA or Roth Buy

This is the harshest version. If you sell at a loss in your taxable account and buy the same security in your IRA or Roth IRA within 30 days, Revenue Ruling 2008-5 confirms the loss is disallowed — and you do not get to add it to the IRA’s basis. The loss is permanently lost, because IRAs have no capital-gain basis to carry it. What to do: never repurchase a sold-at-a-loss security in a retirement account inside the window.

Blind Spot 3: RSU Vesting

Vesting in restricted stock units counts as an acquisition of substantially identical stock. As Financial Finesse explains, if you sell older company shares at a loss within 30 days of an RSU vest, the loss can be disallowed — and “firms are not required to add disallowed losses to the cost basis of equity compensation.” What to do: track your vest dates against any loss sales of company stock.

Blind Spot 4: Your Spouse’s Account or a Controlled Company

The rule treats you and your spouse, and any corporation you control, as one person for wash sale purposes. If you sell at a loss and your spouse buys the same stock within 30 days — even in a separate account at a separate firm — it is a wash sale. The consequence is identical: the loss is disallowed and no broker will flag it. What to do: coordinate trades with your spouse around any tax-loss selling.

Blind Spot 5: “Substantially Identical” Funds and Options

Brokers match on exact CUSIP, so they miss losses paired with a substantially identical — not identical — security. Selling one S&P 500 index fund at a loss and buying a near-clone, or buying a call option on the same stock, can trigger the rule. As Financial Finesse notes, firms are “not required to calculate wash sales on options trading.” What to do: when in doubt, treat a close substitute bought in the window as a wash trigger.

Which Situation Applies to You?

The fix depends on where you are in the process and which blind spot caused the miss. Use this branch to jump to your path.

You are filing your 2025 return right now and just spotted the missed wash sale. Go to the Form 8949 walkthrough below and report it correctly the first time — no amendment needed.
You already filed your 2025 (or an earlier) return and claimed a loss that should have been disallowed. You need to amend with Form 1040-X — see “How to Fix a Return You Already Filed.”
The replacement shares went into an IRA or Roth. Your loss is permanently disallowed and cannot be added to basis — see Blind Spot 2 and Example 3.
The trigger was RSU vesting, a spouse’s buy, or a substantially identical fund/option. The reporting steps are the same; only your record-keeping differs.

How to Fix It on Form 8949 (Step by Step)

Form 8949 is where you list each sale, and its totals flow to Schedule D. To correct a missed wash sale, you report the trade with an adjustment that adds the disallowed loss back. The Form 8949 instructions lay out the columns and the “W” code.

Follow these steps for the lot whose loss is disallowed:

Pick the right part and box. Short-term sales go in Part I; long-term in Part II. Check the box (A, B, D, or E) that matches whether basis was reported to the IRS on your 1099-B.
Column (a) – Description. Enter the security, such as “100 sh XYZ Inc.”
Columns (b) and (c) – Dates. Enter the date acquired and the date sold from your 1099-B.
Column (d) – Proceeds. Enter the sales price (Box 1d).
Column (e) – Cost basis. Enter your basis (Box 1e).
Column (f) – Code. Enter W for wash sale.
Column (g) – Adjustment. Enter the disallowed loss as a positive number. Per TaxSlayer’s instructions, the nondeductible loss goes in as a positive figure.
Column (h) – Gain or loss. Compute (d) minus (e), then add column (g). The positive (g) cancels the disallowed portion of the loss.

The consequence of skipping column (g) is that you claim the full loss and risk a CP2000. The consequence of getting it right is a clean, audit-proof return. Your next step after filing: write the disallowed amount onto the replacement lot’s basis in your own records, because Publication 550 requires you to carry it there. For the mechanics of every line, see our guide on how to fill out Form 8949 and the companion Schedule D walkthrough.

Worked Example: The Math, Step by Step

Numbers make this concrete. Below is a fully worked case you can copy with your own figures, anchored to tax year 2025.

Maria’s cross-broker wash sale. Maria sells 100 shares of XYZ at Schwab on November 10, 2025. She paid $5,000 (basis) and sells for $3,000 (proceeds), a $2,000 loss. Eight days later, on November 18, she buys 100 shares of XYZ at Fidelity for $3,100. Neither broker flags a wash sale, because they are different firms.

Maria’s full loss is disallowed because the replacement buy fell inside the 30-day window. On Form 8949 she reports: column (d) $3,000, column (e) $5,000, column (f) “W”, column (g) $2,000, column (h) $0. The $2,000 is not deductible in 2025.

Maria then adds the $2,000 disallowed loss to her Fidelity basis: $3,100 + $2,000 = $5,100 adjusted basis. Her holding period also carries over from the original lot. When she sells those Fidelity shares later (outside any new wash window) for, say, $4,000, her loss is $4,000 − $5,100 = $1,100 — and that loss is finally deductible. The $2,000 was deferred, not destroyed.

Three Common Scenarios

Below are the three situations that send the most readers searching for this fix. Each shows the move and what it costs you.

Scenario A — Same stock, two brokers

What Happened	What It Means for Your Taxes
Sold ABC at a $2,000 loss at Broker 1; rebought ABC at Broker 2 within 30 days	Loss disallowed; report on Form 8949 with code “W”; add $2,000 to the Broker 2 lot’s basis

Scenario B — Taxable loss, IRA repurchase

What Happened	What It Means for Your Taxes
Sold DEF at a $1,500 loss in a taxable account; bought DEF in a Roth IRA within 30 days	Loss disallowed under Rev. Rul. 2008-5; loss is permanently lost — no basis carryover to the IRA

Scenario C — RSU vest triggers it

What Happened	What It Means for Your Taxes
Sold older company shares at a $3,000 loss; RSUs vested within 30 days	Vest counts as an acquisition; loss disallowed and added to the vested shares’ basis

Two More Named Examples

David’s IRA mistake. David sells GHI in his brokerage account on March 3, 2025, locking in a $1,500 loss. On March 20, he buys GHI in his Roth IRA, not realizing the rule reaches across account types. His $1,500 loss is disallowed, and because IRAs have no capital-gain basis, the loss is gone for good. David reports the sale with code “W” and a $1,500 adjustment in column (g), claiming $0 loss — and learns the costliest version of this rule.

Priya’s spouse trap. Priya sells JKL at a $900 loss in her own account on June 5, 2025. Her husband, in his separate account at another firm, buys JKL on June 12 to “average down.” Because spouses are treated as one taxpayer, Priya’s loss is disallowed. She reports it on her Form 8949 with code “W” and adds the $900 to her husband’s basis in JKL, tracking it in their joint records.

How to Fix a Return You Already Filed

If you already filed and claimed a loss that should have been disallowed, you correct it with Form 1040-X, the Amended U.S. Individual Income Tax Return. You attach a corrected Form 8949 and Schedule D showing the “W” adjustment, and you explain the change in Part II.

The deadline matters. You generally have three years from the date you filed, or two years from when you paid the tax, whichever is later, to amend and claim a refund — though here you are usually adding tax, so file as soon as you can to limit interest. The consequence of waiting: interest keeps running from the original due date, and a long delay can look careless if the IRS finds it first.

Timing and cost: e-filed 1040-X amendments for tax years 2021 and later are accepted electronically, and the IRS says they can take up to 16 weeks to process. Doing it yourself is free aside from software; a CPA typically charges a few hundred dollars for a simple amendment. If multiple years or large dollar amounts are involved, that fee is usually worth it.

Mistakes to Avoid

Each of these errors carries a specific cost. Learn them before you file.

Trusting the 1099-B blindly. Brokers only catch same-account, same-CUSIP wash sales, so a “clean” 1099-B can hide a disallowed loss — and the IRS still expects the adjustment.
Forgetting to add the loss to the replacement basis. Skip this and you lose the deferred deduction forever when you eventually sell.
Repurchasing in an IRA or Roth. This permanently destroys the loss with no basis carryover, the worst outcome of all.
Ignoring your spouse’s trades. Spouses count as one taxpayer; an uncoordinated buy disallows your loss with no warning.
Entering the column (g) adjustment as a negative. It must be a positive number, or your math overstates the loss.
Missing “substantially identical” substitutes. A near-clone fund or an option on the same stock triggers the rule even with a different CUSIP.
Aggregating wash sale trades into a summary total. Wash sale lots must be listed separately on Form 8949, not lumped into a 1099-B summary line.

Do’s and Don’ts

Do’s

Do gather every 1099-B from every firm, because cross-broker wash sales only surface when you see all accounts together.
Do track RSU vest dates, since a vest inside the window can quietly disallow a loss.
Do add disallowed losses to replacement basis, so you recover the deduction later.
Do keep your own wash sale log, because brokers will not do it for cross-account trades.
Do amend promptly if you already filed, to stop interest from compounding.

Don’ts

Don’t rebuy a loss security in an IRA, because the loss disappears with no recovery.
Don’t assume different brokers are “safe,” since the rule ignores firm boundaries.
Don’t claim a loss the rules disallow, or you invite a CP2000 and interest.
Don’t forget the carried-over holding period, which affects long-term versus short-term treatment.
Don’t guess on “substantially identical,” because the IRS reads it broadly.

Pros and Cons of the Wash Sale Rule

Pros

It defers, not destroys, most losses, so you usually still get the deduction eventually.
The holding period carries over, which can push you into lower long-term rates.
It prevents abusive paper losses, keeping the tax system fair.
The fix is mechanical, a single code and adjustment on Form 8949.
Self-reporting puts you in control, since you see all accounts the broker cannot.

Cons

It can permanently kill a loss when the rebuy lands in an IRA or Roth.
It creates a heavy record-keeping burden across brokers, RSUs, and spouses.
Brokers’ partial reporting misleads taxpayers into thinking they are covered.
“Substantially identical” is vague, leaving gray areas the IRS can challenge.
Errors can trigger notices and interest, even when honest.

What to Do Next

Take these steps in order, starting today.

Collect every 2025 Form 1099-B from all brokers, plus RSU vesting statements and your spouse’s trade history.
Scan for any loss sale with a matching buy within 30 days across all accounts, funds, options, and IRAs.
Report each disallowed loss on Form 8949 with code “W” in column (f) and the loss as a positive number in column (g).
Write the disallowed amount onto the replacement lot’s basis in your own records for future sales.
If you already filed, prepare Form 1040-X with a corrected 8949 and Schedule D, and file it promptly.
Call a CPA or tax attorney if you have many trades, IRA-crossed losses, or multiple amended years — this is when professional help pays for itself.

This article is educational and is not a substitute for advice from a licensed tax professional about your specific situation.

FAQs

Do brokers always report wash sales?

No. Brokers only report wash sales within the same account, at the same firm, for the same security (CUSIP) under the cost-basis rules. Cross-broker, IRA, spouse, RSU, and substantially-identical-fund wash sales are your responsibility for tax year 2025.

What code do I use on Form 8949 for a wash sale?

Code “W.” Enter it in column (f), then put the disallowed loss as a positive number in column (g) so it offsets the loss in column (h). This applies for the 2025 tax year and every year.

Is the disallowed loss gone forever?

No, usually it is deferred. You add it to the replacement shares’ cost basis and claim it when you later sell them outside a wash window. The exception is a repurchase inside an IRA, where it is lost permanently.

Does a wash sale apply across two different brokers?

Yes. The rule follows you, not the account. Selling at a loss at one firm and buying the same security at another within 30 days is a wash sale, even though neither 1099-B will flag it.

Can buying in my IRA trigger a wash sale on a taxable loss?

Yes. Under Revenue Ruling 2008-5, selling at a loss in a taxable account and buying the same security in your IRA or Roth within 30 days disallows the loss — and you cannot add it to the IRA basis.

Do RSUs cause wash sales?

Yes. Vesting in RSUs counts as acquiring substantially identical stock. Selling older company shares at a loss within 30 days of a vest can disallow that loss, and brokers do not adjust RSU basis for it.

How do I fix a wash sale on a return I already filed?

File Form 1040-X. Attach a corrected Form 8949 and Schedule D showing the code “W” adjustment, and explain the change. Do it promptly, since interest runs from the original due date.

How long do I have to amend?

Generally three years. You have three years from filing or two years from paying the tax, whichever is later, to amend. Because a wash sale fix usually adds tax, file as soon as possible to limit interest.

What happens if I ignore a missed wash sale?

The IRS can disallow it. Its matching system compares your 1099-B to your return; an overstated loss can trigger a CP2000 notice that recomputes your tax and adds interest, and possibly a penalty.

Does my state follow the federal wash sale rule?

Most do. States that base income tax on federal adjusted gross income generally honor the wash sale rule automatically. Confirm with your state tax agency, since conformity and timing can vary, especially in states with their own basis rules.

What counts as “substantially identical”?

Same or near-clone securities. Identical stock, options on it, and very similar index funds can qualify; different companies in the same sector usually do not. The IRS reads it broadly, so treat close substitutes as triggers.

Can I just lump wash sale trades into a 1099-B summary?

No. Wash sale transactions must be listed separately on Form 8949 with the “W” code; they cannot be folded into an aggregated summary line for tax year 2025.

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