More or less stock bought than sold.
If the number of shares of substantially identical stock or securities you buy within 30 days before or after the sale is either more or less than the number of shares you sold, you must determine the particular shares to which the wash sale rules apply. You do this by matching the shares bought with an equal number of the shares sold. Match the shares bought in the same order that you bought them, beginning with the first shares bought. The shares or securities so matched are subject to the wash sale rules.
Example 1. You bought 100 shares of M stock on September 21, 2020, for $5,000. On December 14, 2020, you bought 50 shares of substantially identical stock for $2,750. On December 21, 2020, you bought 25 shares of substantially identical stock for $1,125. On January 4, 2021, you sold for $4,000 the 100 shares you bought in September. You have a $1,000 loss on the sale. However, because you bought 75 shares of substantially identical stock within 30 days before the sale, you cannot deduct the loss ($750) on 75 shares. You can deduct the loss ($250) on the other 25 shares. The basis of the 50 shares bought on December 14, 2020, is increased by two-thirds (50 ÷ 75) of the $750 disallowed loss. The new basis of those shares shares bought on December 21, 2020, is increased by the rest of the loss to $1,375 ($1,125 + $250).
Example 2. You bought 100 shares of M stock on September 17, 2020. On January 29, 2021, you sold those shares at a $1,000 loss. On each of the 4 days from February 2, 2021, to February 5, 2021, you bought 50 shares of substantially identical stock. You cannot deduct your $1,000 loss. You must add half the disallowed loss ($500) to the basis of the 50 shares bought on February 2. Add the other half ($500) to the basis of the shares bought on February 3.
