Form 1099-B reports the sale of stocks, bonds, mutual funds, and other securities you sold through a brokerage account during the tax year.

Your brokerage firm — whether that is Fidelity, Charles Schwab, E-Trade, or your bank's investment division — sends you a 1099-B for every sale you made. The form shows what you sold, when you sold it, how much you received, and sometimes what you originally paid for it. The IRS gets a copy too, which is why the numbers on your 1099-B need to match what you report on your tax return.

You use 1099-B information to calculate capital gains or losses on Schedule D of your tax return. A capital gain happens when you sell something for more than you paid for it; a capital loss happens when you sell it for less. The IRS taxes gains and allows you to deduct losses (within limits), so getting the numbers right matters.

Key Takeaways

  • Your brokerage sends 1099-B for every stock, bond, mutual fund, or security sale you made during the year.
  • The form shows the sale price, the date sold, and sometimes the cost basis — what you originally paid.
  • You report 1099-B sales on Schedule D to calculate capital gains or losses for your tax return.
  • If your brokerage did not report cost basis, you must find your original purchase records to calculate the gain or loss yourself.
  • You must report all sales even if you did not receive a 1099-B, so keep your own records of trades.

What Information Appears on Form 1099-B

Box 1a on the form shows the gross proceeds — the total amount of money you received when you sold the security. This is not your profit; it is the full sale price before any costs or taxes.

Box 1b shows the cost basis if your brokerage calculated it. Cost basis is what you originally paid for the security, including any commissions or fees. If this box is blank, your brokerage either did not have the information or you bought the security before they started tracking it, and you will need to find your own records.

Box 2 shows the date you sold the security. This matters because the IRS treats sales held for more than one year (long-term capital gains) differently from sales held one year or less (short-term capital gains). Long-term gains usually have lower tax rates.

Boxes 3 through 6 contain details about the security itself — the description, the quantity, and sometimes the CUSIP number (a unique identifier for the security). These help you match the 1099-B to your own records.

How to Match Your 1099-B to Your Brokerage Records

Before you report anything on your tax return, pull up your brokerage account statements for the year and compare them to the 1099-B. Check that the sale dates, quantities, and sale prices match. If your brokerage shows a sale on December 15 but the 1099-B says December 20, contact the brokerage — one of them is wrong.

If cost basis appears on the 1099-B, verify it against your purchase confirmations. Some brokerages calculate basis incorrectly, especially if you reinvested dividends, received a stock split, or bought the same security at different times. If the basis looks wrong, note the discrepancy and use your own records instead.

Keep the 1099-B and your brokerage statements together in your tax file. You do not send the 1099-B to the IRS — your brokerage does — but you need it to fill out Schedule D, and you should keep it for at least three years in case the IRS asks questions.

Reporting Sales on Schedule D When You Have Cost Basis

If your 1099-B shows cost basis in Box 1b, you have the information you need. On Schedule D Part I (for short-term sales) or Part II (for long-term sales), enter the sale date, the description of the security, the quantity, the sale price from Box 1a, the cost basis from Box 1b, and the gain or loss (sale price minus cost basis).

The IRS matches the numbers on your Schedule D to the 1099-B your brokerage filed, so they must be exact. If you round or estimate, the IRS computer will flag the discrepancy. Use the exact figures from the 1099-B.

At the bottom of Schedule D, you total all your short-term gains and losses and all your long-term gains and losses. The net result — your overall capital gain or loss for the year — transfers to your Form 1040.

What to Do If Cost Basis Is Missing or Wrong

If Box 1b is blank, you must find your original purchase confirmation or brokerage statement showing what you paid. If you bought the security years ago and no longer have the statement, contact the brokerage and ask for a historical account statement or trade confirmation. Most brokerages keep records for at least seven years.

If you cannot find the original cost, you have a problem: you cannot calculate the gain or loss without it, and the IRS will not accept an estimate. Some taxpayers in this situation contact the brokerage a second time and ask them to research the purchase. If the brokerage cannot find it either, you may need to report the entire sale price as gain, which is the worst outcome. This is why keeping your own records matters.

If the cost basis on the 1099-B is wrong — for example, it does not account for a stock split or dividend reinvestment — you can report the correct basis on Schedule D and attach a note explaining the difference. Keep your supporting documents in case the IRS asks.

Sales That Require Special Handling

Mutual fund sales sometimes appear on multiple 1099-Bs if you sold shares in different lots or at different times during the year. Each sale is a separate transaction, and you report each one separately on Schedule D.

If you sold a security at a loss, you can use that loss to offset capital gains from other sales. If your total losses exceed your total gains, you can deduct up to $3,000 of the net loss against other income (such as wages or interest). Any loss above $3,000 carries forward to future years.

Wash sales — when you sell a security at a loss and buy the same or a substantially identical security within 30 days before or after the sale — have special rules. The loss is disallowed, and the cost basis of the new purchase is adjusted upward. Your brokerage may flag wash sales on the 1099-B, but you are responsible for tracking them correctly.

When You Receive Multiple 1099-Bs or None at All

If you have accounts at more than one brokerage, you will receive a separate 1099-B from each one. You report all of them on the same Schedule D. Add them all up to get your total capital gains or losses for the year.

If you made sales but did not receive a 1099-B, you still must report them. This can happen if you sold securities through a broker that is not required to file 1099-Bs (some smaller or international brokers), or if the brokerage made an error. Use your own trade confirmations and statements to fill out Schedule D. The IRS may not have a matching 1099-B on file, but you are still required to report the sale.

If you received a 1099-B for a sale you did not make, or if the information is clearly wrong, contact the brokerage when ready and ask for a corrected form (a 1099-B with a "Corrected" checkbox marked). The brokerage will file the corrected version with the IRS and send you a copy.

Frequently Asked Questions

Do I have to report a 1099-B if I had a loss?

Yes. You report all sales on Schedule D, whether they resulted in gains or losses. Losses offset gains and can reduce your taxable income, so reporting them is to your benefit. The IRS expects to see all 1099-Bs you received.

What if my 1099-B shows a different sale price than my brokerage statement?

Contact the brokerage and ask which number is correct. The 1099-B may show the net proceeds (after commissions), while your statement shows the gross sale price, or vice versa. Get clarification in writing before you file your return.

Can I report a lower cost basis than what the 1099-B shows?

You can report a different basis if you have documentation showing the 1099-B is wrong — for example, if a stock split or dividend reinvestment was not accounted for. Attach a note to your return explaining the difference and keep your supporting documents. Do not straightforward guess a lower number.

What happens if I do not report a 1099-B sale?

The IRS receives a copy of every 1099-B your brokerage files. If you do not report a sale, the IRS computer will eventually notice the mismatch and may send you a notice or bill you for the tax owed plus penalties and interest. Reporting the sale, even if you made a mistake, is always better than not reporting it.

Do I need to attach the 1099-B to my tax return?

No. You keep the 1099-B in your records but do not send it to the IRS. Your brokerage files it separately. However, if the IRS asks about a specific sale, you will need to produce the 1099-B and your supporting documents.