What the Wash-Sale Rule Actually Blocks
Sell a losing stock and buy it back within 30 days, and the IRS wipes out your tax deduction for the year, not just on the sale date but across a 61-day window surrounding it. The loss doesn't vanish forever. But where does it actually go, and when does it come back to help you?
- The 61-day window covers 30 days before the sale, 30 days after, plus the sale date itself.
- There's a $3,000 annual limit on how much in capital losses can offset ordinary income once they exceed capital gains.
- "Substantially identical security" is the IRS standard here, and it covers more than just the same stock. Options and convertible bonds tied to it often count too.
- Tax-loss harvesting, the broader strategy of selling losers to offset gains, runs straight into this rule at every turn.
Investors who actually track this 61-day window can time trades to keep their deductions instead of losing them to a careless mistake. Skip that step and a legitimate tax strategy turns into a wasted transaction, no deduction, nothing to show for it on this year's return. The good news: that deduction isn't gone for good. It's postponed. Figuring out where it goes is what separates people who use the rule from people who keep getting burned by it.
How the Disallowed Loss Follows Your Money
A wash sale defers the loss, it doesn't destroy it. The IRS tacks the disallowed amount onto the cost basis of your replacement security, and the holding period from the original shares carries over too. The tax benefit comes back eventually, just not on the return you were hoping to file this year.
- The cost basis adjustment raises your replacement security's basis by roughly the disallowed amount, which shrinks your taxable gain down the road.
- Holding period carryover means the clock from your original shares transfers to the new ones, so you keep long-term capital gains treatment if you'd already earned it.
- None of it helps you this year. The loss can't offset capital gains or chip away at that $3,000 ordinary income limit on the return you're filing now.
- Brokerages report wash sales on Form 1099-B, and this is exactly where a lot of investors get blindsided at tax time, expecting a deduction that's already been disallowed.
- Buy the same security inside a retirement account during that window and there's no basis adjustment waiting for you. The loss just disappears, full stop.
Say you're harvesting losses to shelter gains from a strong market year. An accidental wash sale means that deduction vanishes from this year's tax bill and shows up later, worth less in practical terms, whenever you eventually sell the replacement shares. The rule rewards patience. Wait out the 30 days, or buy something correlated but not identical, and your deduction stays right where you wanted it, on this year's return. So where does the loss go? It moves into the cost basis of your new position and sits there waiting. The only way to lose it for real is to keep repeating the mistake inside a retirement account, where there's no basis adjustment left to bail you out.