| 1. | a sale of a stock at a loss and repurchase of the same or substantially identical stock within 30 days, for which the capital loss is disallowed for tax purposes. |
| 2. | the simultaneous purchase and sale of large amounts of a stock or commodity by the same speculator so as to give a false appearance of wide market activity and interest in the stock or commodity. |

| wash sale n. The illegal buying of stock by a seller's agents to give the impression of an active market. |
Wash Sale
An illegal transaction an investor makes by simultaneously buying and selling a security through two different brokers, thereby creating the illusion of activity. Investors do this to try and recognize a tax loss without actually changing their position.
Investopedia Commentary
The effectiveness of this strategy has been greatly diminished with the implementation of the IRS 30-day wash rule, where a taxpayer cannot recognize a loss on an investment if that investment was purchased withing 30 days of sale (before or after sale).
Related Links
Selling Losing Securities for a Tax Advantage
Five Tips for the Tax-Smart Investor
See also: Crystallization, Daisy Chain, Paper Profit (or Loss), Wash, Wash Sale Rule
wash sale