Wash trading occurs when an investor sells a security at a loss, then purchases the same or a substantially similar security within 30 days of the sale.
Let's assume an investor owns 100 shares of XYZ Company and sells these shares on May 1 for a $1,000 loss. Then the investor purchases 100 new shares of XYZ Company on May 5 and sells those shares for a $2,000 gain.
In this situation, the investor might attempt to claim a tax deduction for the initial $1,000 loss. The would offset the tax due on the subsequent $2,000 gain, meaning that the investor would pay less tax on the gain even though his position in the never materially changed. However, because the investor purchased the second set of shares within 30 days of the sale of the first set of shares, the IRS tax the investor on the full $2,000 gain from the second transaction.
The window spans 61 days: 30 days before the sale, the day of the sale, and 30 days after the sale.
Claiming deductible, selling securities at a loss in order to get a and then buying the back right away allows tax evaders to create synthetic tax deductions without really changing their economic positions in a security. Thus, the Tax Reform Act of 1984 allows the to prohibit from deducting losses on the sale of an investment if the repurchases the same security 30 days before or after the sale. This is called the thirty-day rule.
The Exchange Act has similar prohibitions regarding wash trading, and wash trading also violates Section 9(a)(1)(A) and Rule 10b-5 of the Securities Exchange Act of 1934. The focus of these rules is on preventing conspiracies to artificially inflate a security's price by engaging in wash trading, which increase the perceived trading of a security and therefore induce legitimate trades by other investors.
The IRS rule applies to very similar securities, meaning that transactions involving options, warrants, certain types of preferred stock, and short sales on the security in question within the thirty-day period may count as wash trading. The rule also applies to a taxpayer's spouse, meaning that a loss-generating sale by one and subsequent purchase by the other may be considered a wash trade, as may agreements among friends to repurchase securities from each other when the period ends. Further, the IRS does not require that the same number of similar securities be traded in each part of the transaction to count as a wash trade.
There is some controversy regarding whether using two or more to execute a wash transaction (that is, using one broker for the sale and a different broker for a purchase within the 30-day window) is legal, and many financial consultants and tax professionals advise against this situation.
When a wash trade does occur, the investor must add the loss to the basis of the most recently purchased, substantially similar securities. This addition increases the cost basis of the purchased securities and reduces the size of any future as a result. Thus, the investor still receives "credit" for those losses, but at a later time.