The IRA Wash-Sale Trap That Erases Your Tax Loss for Good

Priya harvested a $9,000 loss last December, filed her taxes in April, and learned the loss was worth nothing. Not deferred to next year. Gone. She had sold a total-market index fund in her taxable brokerage to cancel out a $9,000 gain she'd taken earlier in 2025, a move worth about $1,350 at her 15% capital-gains rate. Then, a week later, she bought the exact same fund back inside her Roth IRA, because she still liked it and figured her retirement account was the smarter place to hold it.

That second decision, the one that felt tidy and tax-smart, is what killed the deduction. Permanently.

Most people who tax-loss harvest know the wash-sale rule exists. What almost nobody knows is that the rule has a special, much nastier version when an IRA is involved. In a normal wash sale, your loss is only paused. In the IRA version, it's destroyed. And because your brokerage will never warn you, this is one of those mistakes you only find out about long after it's too late to fix.

The rule everyone half-remembers

The wash-sale rule lives in Section 1091 of the tax code. It says you can't claim a loss on a security if you buy the same or a "substantially identical" security within 30 days before or 30 days after the sale. Add the two 30-day sides plus the day of the sale itself and you get a 61-day danger zone.

The point of the rule is to stop you from selling purely for the tax deduction while never actually giving up your position. If you dump a fund on Monday and rebuy it Wednesday, you never really left the market, so the IRS won't let you book the loss.

Here's the part that matters: "substantially identical" is the phrase carrying the whole rule, and the IRS has never drawn a bright line around it. Publication 550 states the principle and leaves the edges blurry. In practice, selling one company's total-market fund and buying a different company's S&P 500 fund is widely treated as safe, because they track different indexes. Selling a fund and buying the identical fund back, in any account you or your spouse control, is not.

Where the loss usually goes

In an ordinary wash sale, the loss isn't lost. It moves.

Say you buy a fund for $10,000, sell it at $6,000 for a $4,000 loss, then rebuy the same fund in your regular taxable account inside the window. The IRS disallows the $4,000 loss for now, but it adds that $4,000 to the cost basis of your replacement shares. When you eventually sell those, your taxable gain is $4,000 smaller. You get the benefit back later. It's a timing penalty, not a death sentence.

This is exactly how the standard guides describe it, and for a taxable-to-taxable rebuy, they're right. The disallowed loss rides along inside your new basis, waiting for you.

That safety valve is the whole reason a normal wash sale is survivable. And it's the exact thing that disappears the moment the replacement shares land in an IRA.

The IRA version: the loss just dies

In 2008 the IRS closed a loophole with Revenue Ruling 2008-5. People had figured out they could sell a loser in their taxable account to harvest the loss, then rebuy it inside their IRA to keep the exposure, dodging the wash-sale rule on a technicality. The IRS said no. A loss sale in your taxable account paired with a purchase of the same security in your IRA is a wash sale, same as any other.

But then the ruling went further, and this is the sharp edge. Under Section 1091(d), the disallowed loss is supposed to attach to the basis of the replacement shares. The problem is that shares held inside a traditional or Roth IRA don't carry a cost basis that ever does you any good. Your IRA is a tax shelter; gains and basis inside it are invisible to your tax return. So there's no usable basis for the loss to attach to. It doesn't defer. It vanishes.

Michael Kitces, the financial planner behind kitces.com, put it plainly when the ruling came out: the loss is "permanently forfeited." There's no later sale that recovers it, no carryforward, no basis bump you can ever cash in. The money is simply gone.

That table is Priya's whole story in four rows. Had she rebought her fund in a second taxable account, she'd have simply waited to claim the $1,350. Because she rebought it in her Roth, the $1,350 evaporated.

Three ways people trigger it without meaning to

The deliberate version, harvesting in taxable and rebuying in the IRA on purpose, is what the ruling was written to stop. But the accidental versions catch far more people, and they're getting more common as automated investing spreads.

Your automatic contributions keep buying

This is the modern trap. You harvest a loss on a broad index fund in your brokerage. Meanwhile, your IRA has a standing instruction, set up years ago and forgotten, to invest each monthly contribution into that same index fund. A buy lands nine days after your sale, and part of your loss is washed. Direct indexing and robo-advisors, which now run automated harvesting across more than a trillion dollars in U.S. assets and are projected to hit roughly $800 billion in direct-indexed portfolios in 2026, make this collision far easier, because the buying and selling happen on schedules you're not watching.

Worth knowing: only the loss on the number of shares actually repurchased gets disallowed. If your automatic IRA buy was small relative to what you sold, only a slice of the loss dies. Small comfort, but it means a $50 recurring buy doesn't nuke a $9,000 harvest, just the piece that matches.

Your spouse buys it in their account

The rule reaches across your household. If you sell a fund at a loss and your spouse buys the same fund inside the window, the IRS treats it as your wash sale, whether you file jointly or separately. If your spouse's purchase happens inside their IRA, you're back in permanent-loss territory. Two people managing two sets of accounts and never comparing notes is all it takes.

You "relocate" the fund to shelter it

This was Priya's exact mistake, and it comes from good instincts. You harvest the loss, and separately you decide the fund really belongs in your tax-advantaged account where its future growth won't be taxed. Both moves make sense alone. Done within 61 days of each other on the identical fund, they combine into a permanently forfeited loss.

Why your broker won't save you

You might assume your brokerage flags wash sales for you. It does, but only partly. Firms are required to track and report wash sales within a single account at a single firm for identical securities. They do not track across your different accounts, across account types, across firms, or across your spouse's login.

So the taxable-to-IRA wash, the exact one that triggers permanent loss, is the one your 1099 is least likely to catch. It falls in the blind spot between two systems that don't talk to each other. The responsibility to identify it is yours, and if you miss it, you may claim a loss you weren't entitled to and quietly overstate a benefit that the rules already erased.

How to harvest without stepping on the mine

None of this means tax-loss harvesting is a trap to avoid. It's a good strategy, and losses are valuable. A harvested loss offsets your capital gains dollar for dollar, and up to $3,000 of leftover loss each year comes straight off your ordinary income. That $3,000 cap, by the way, hasn't moved since 1978 and isn't indexed to inflation, according to the Congressional Research Service, so a big loss can take a decade to fully use. A $30,000 loss with no gains to offset would need ten years of $3,000 deductions to burn off. Every dollar of that is worth protecting from an accidental wash.

The fix is coordination, not avoidance. When you harvest, treat the 61-day window as covering every account you and your spouse touch, not just the one you sold from. Pause any automatic investments and dividend reinvestment on the harvested fund across your IRAs and 401(k)s for the window. When you reinvest to stay in the market, buy a similar-but-not-identical fund, a different provider's fund tracking a different index, so you keep your exposure without tripping the rule. And if you truly want the fund in your IRA, wait until day 31 has cleared before buying it there.

The Bottom Line

The wash-sale rule is survivable in a taxable account and lethal in an IRA. Treat the two very differently, and do these four things before you harvest your next loss:

• Map every account first. List your taxable accounts, both spouses' IRAs and 401(k)s, and any robo or direct-indexing account. The 61-day window covers all of them at once.
• Freeze the autopilot. Turn off recurring contributions and dividend reinvestment on the specific fund you're harvesting, in every account, for the 61 days around your sale.
• Reinvest into a cousin, not a twin. Swap into a fund that tracks a different index from a different provider so you stay invested without buying something "substantially identical."
• Never rebuy the harvested fund in an IRA inside the window. If you want it there, wait past day 31. Inside the window, that one purchase turns a delayed benefit into a deleted one.

Priya's $1,350 is gone, and there's no form to get it back. Yours doesn't have to go the same way. Spend ten minutes checking your automatic buys before you sell, and the loss you harvest stays yours to keep.