Wash Sale Rule
Also called: wash sale, bed and breakfasting rule
The wash sale rule disallows a capital loss if you buy a substantially identical security within 30 days before or after the sale. The loss isn't lost — it's added to the new position's cost basis and deferred. It applies across your accounts, including an IRA purchase, where the loss is permanently forfeited rather than deferred. Buying a different fund tracking a different index is the usual way to stay invested without triggering it.