2026 tax-loss harvesting: the dates that matter
| Thursday, December 31, 2026 | Last trade date for a sale to count in tax year 2026. For stocks and ETFs the trade date, not the settlement date, decides the year. |
| December 1, 2026 | A loss sale on Dec 1 has a wash-sale window that ends Dec 31: buying the same security from Nov 1 through Dec 31 (in any account) disallows the loss. |
| 30 days before and after | The wash-sale window runs 30 calendar days on each side of the sale date, 61 days in total. |
| Early January 2027 | Buys of the same security in the first days of January can still disallow a loss sold in late December, and the disallowed loss moves into 2027. |
| Mid-February 2027 | Brokers send Forms 1099-B. They only flag wash sales inside one account. |
| April 15, 2027 | Filing deadline for 2026 returns. |
Three traps
- The IRA buy. Selling at a loss in a taxable account and buying the same security in an IRA within 30 days loses the deduction for good.
- Dividend reinvestment. An automatic reinvestment within 30 days is a purchase and can wash part of the loss.
- The 300-364 day gain. A winning lot sold a few weeks before its one-year mark is taxed at short-term rates. See the difference.
Run the Year-End Check Free wash-sale calculator
General information, not advice. Confirm your situation with a tax professional.