Financial institutions report sales of investment property to the IRS and their clients on Form 1099-B, Proceeds From Broker and Barter Exchange Transactions or a substitute statement. Form 1099-B may show either gross proceeds or net proceeds.
If gross proceeds and selling expenses are separately stated on Form 1099-B, include on Schedule D the gross proceeds amount in column (d) and add the selling expenses to the cost basis in column (e).
If only net proceeds are reported on Form 1099-B, report the net amount as the sales price in column (d) of Schedule D.
Do not include selling expenses in column (e).
List Form 1099-B transactions on Form 8949 before completing Schedule D.
Form 8949 provides two sections:
In addition, in each section of Form 8949, you must check one of three boxes (Box A, B, or C).
Keep in mind, you checkmark only one of the three boxes shown in Part 1 and Part II of Form 8949.
If the cost or other basis of securities you've sold is not reported on Form 1099-B, in other words, box 3 is blank, you must use a separate Form 8949 to list these types of transactions.
If instead of Form 1099-B for each individual transaction, you receive a substitute statement showing multiple transactions, the broker will indicate on the substitute statement whether basis for a transaction was reported to the IRS or was not reported to the IRS.
You must complete a separate Form 8949 to cover each of the three situations described above.
In other words...
You receive a Form 1099-B substitute statement showing multiple transactions:
For these transactions you need two Forms 8949: one to report the two transactions with basis reported by the broker to the IRS. And a second Form 8949 to report the transaction where no basis was reported to the IRS.
If you had gains and losses from capital transactions that were not reported to you on Form 1099-B, you would have to prepare another Form 8949 to report such transactions.