Deferred losses

Yes, when you are allowed and able to enter it correctly. A deferred loss happens when you have a wash sale. The deferred loss is added to the basis of the stock that was repurchased. It is your responsibility to ensure you keep up with your basis.

For example:

Buy ABC 100 shares for $4,000 - date irrelevant

Sell ABC  100 shares April 1 for $2,000 0 could be a $2k loss

Buy ABC 50 shares  April 28 for $1,200

A purchase between April 2 and May 1, that is 30 days either side of the sale, you have a wash sale. So the wash is added to the basis and the most recent purchase is your purchase date.

However, only half the shares were purchased a second time. So half is a loss and half is a wash (deferred loss). The outcome here is: 

• $1,000 loss on 50 shares bought and sold
• $1,000 wash is added to the basis of the new stock, new basis is $2200 and purchase date is the new one 4/28.

I want to urge you to create a financial notebook that is kept separate from your tax return. Keep it safe and each year, add your year-end statements from all your financial accounts plus a copy of your W2’s, your  carryover information, and proof of your basis in your various investments. You must keep tax records  from the time you purchase until sold/ loss used plus 3 years. It is very easy to lose track of disallowed losses, wash sales, carryforwards,  and basis. This can be a digital or paper notebook.

Reference: About Publication 550, Investment Income and Expenses