7. Form 1099-B, which you receive from your broker by mid-February, reports all your stock sales from the prior year. It shows (in Box 1g) the amount of any nondeductible loss stemming from a wash sale involving covered securities (at least for those in the same account). Note that many brokerage firms reformat Form 1099-B into their own substitute statement that has columns labeled same as the boxes on the IRS form.