Tax-loss harvesting deadline for 2026: the dates that matter
By Wash-Sale Guardian (who's behind it) · Published 2026-10-02 · Last updated 2026-10-02 · How the checker works
The last trading day of 2026 is Thursday, December 31, and the trade date, not the settlement date, decides the tax year. If you want to realize a loss and buy the same stock back before year-end, the last loss sale that works is Monday, November 30. Every later sale has a wash-sale window that runs into January 2027.
The dates for tax year 2026
| Date | What it means |
|---|---|
| Mon Nov 30, 2026 | Last day to sell at a loss and still re-buy the same stock within 2026 without a wash sale. The 30-day window after a Nov 30 sale ends Dec 30, so a Dec 31 re-buy falls outside it. |
| Thu Dec 31, 2026 | Last trading day of 2026. A sale belongs to tax year 2026 if its trade date is on or before today; settlement date does not matter (IRS Publication 550). |
| Dec 1 or later | A loss sold on Dec 1 or any later date has its first re-buy date with no overlap from that sale in January 2027. |
| Dec 31 → Jan 30, 2027 | The window does not stop at New Year’s. A late-December loss is washed by a same-ticker re-buy for 30 days after its own sale date, and that runs into January 2027. The window for a Dec 31 sale ends Jan 30; a Dec 18 sale’s ends Jan 17. It counts in any account, including IRAs and a spouse’s accounts. |
All of these follow from the 61-day window: 30 days before the loss sale, the sale day, and 30 days after, counted in calendar days across the year boundary.
The December-to-January trap
The window does not reset on January 1. A loss sold on Monday, December 21, 2026 is washed by a same-ticker re-buy on Monday, January 11, 2027, and the loss comes off the 2026 return. For a December 31 sale the window runs through Saturday, January 30, 2027; a December 18 sale's window ends January 17. The re-buy counts in any account you own, including an IRA, and in a spouse's account (why every account counts).
Deferred, not lost, except in an IRA
In an ordinary wash sale the disallowed loss is not gone: it is added to the basis of the replacement shares and comes back when those shares are sold (IRS Publication 550). The exception is a replacement purchase inside your own traditional or Roth IRA. Under Rev. Rul. 2008-5 that loss is disallowed permanently, with no basis adjustment, and a 1099-B is not required to show it (the IRA explainer).
Before you harvest
- Look back 30 days in every account, yours, your IRAs and your spouse's, for a buy of the same ticker, including dividend reinvestment and scheduled purchases.
- Note which scheduled buys and dividend reinvestments could fire in any account before the window closes.
- Write down the sale date plus 31 days as the first date with no overlap from that sale (the first clean re-buy date), and check whether any replacement is substantially identical, which includes a call option on the same stock.
The year-end wash-sale checklist has the full one-page version, including the January reconciliation, as a page and a printable PDF.
Why the checker exists: your other accounts
Each broker sees only its own account, so none of them can tell you that your IRA, your spouse's account or a second brokerage bought the stock you just sold. The IRS counts all of them. Our free checker reads your brokers' CSV exports in your browser, nothing uploaded, and lists the cross-account wash sales it finds in the trades you import and the open 30-day windows.
Run the free checker → See it on example trades
Not tax advice. Sources: IRS Publication 550 · IRC §1091 · Rev. Rul. 2008-5. Confirm your own situation with a CPA.
Frequently asked questions
What is the deadline for tax-loss harvesting in 2026?
Thursday, December 31, 2026, the last trading day of the year. The trade date, not the settlement date, decides the tax year (IRS Publication 550). If you want to sell at a loss and re-buy the same stock within 2026 without a wash sale, the last loss-sale date is Monday, November 30, 2026.
Can I sell at a loss on December 31 and re-buy right away?
A same-ticker re-buy inside the 61-day window makes it a wash sale. For a December 31 sale the window runs through Saturday, January 30, 2027. The first calendar day after it is Sunday, January 31, 2027, and the first trading day is Monday, February 1, 2027. Each sale’s own window ends 30 days after that sale (a December 18 sale’s ends January 17, 2027). A re-buy in any of your accounts, including IRAs and a spouse’s accounts, counts.
Is a wash-sale loss lost forever?
Usually not. The disallowed amount is added to the basis of the replacement shares and comes back when they are sold (IRS Publication 550). The exception is a replacement bought inside your own traditional or Roth IRA, where Rev. Rul. 2008-5 disallows the loss permanently with no basis adjustment.
Get the year-end wash-sale reminders
Short emails at the moments that matter: before Nov 30 (the last day to sell at a loss and still re-buy within 2026); before Dec 31; when 1099-Bs arrive in February; and the day Guardian Pro goes on sale. The one-page year-end checklist PDF comes with it.
Sign up and a link to the PDF appears right here. Confirm the email we send and you're on the list: about four to six emails a year, and you can unsubscribe in one click from any of them. Your trades stay in your browser. The form sends Kit only your email address and the page you signed up from — nothing else (see Privacy).