Wash sale rule: the 30-day ETF window (2026)

If you sell a stock or ETF at a loss and buy the same or a substantially identical security within 30 days before or after the sale, the wash sale rule disallows the loss. The disallowed amount is added to the basis of the replacement shares, so the loss is deferred.

The window is 61 days in total: 30 days before the sale, the sale date, and 30 days after. A near-clone ETF can fall inside that window. Dividend reinvestment and options can too. A Form 1099-B can flag some wash sales across accounts and miss others.

Wash-sale disallowance currently applies more clearly to stocks and securities than to cryptocurrency treated as property. That distinction matters for loss harvesting, but tax law can change. Verify current IRS guidance before relying on crypto-specific harvesting.

The stocks calculator includes an optional wash-sale checkbox so you can see a planning warning. It is not a substitute for tracking replacement purchases across every account.