Form 1099-B

After tax season rolls around, you'll find a 1099-B waiting from every brokerage or exchange where you sold investments. Think of it as a receipt for all your trades that year—it tells the IRS (and you) exactly what you sold and for how much.

Each line on the form shows the sale date, what you received, what you originally paid (the cost basis, if your broker has it), and whether the gain or loss counts as short-term or long-term. Starting in 2025, crypto exchanges are required to issue these forms for digital asset sales too—a big shift from the old days when crypto investors had to piece everything together themselves.

Your 1099-B feeds directly into Schedule D and Form 8949 on your tax return. If your broker reported the cost basis correctly, you can often just use the summary totals. If cost basis is missing—common for older purchases or crypto—you'll need to list each transaction individually on Form 8949.

One thing to watch out for: transferred securities. If you moved shares from one broker to another, the new broker might not have your original purchase price. That means the cost basis on your 1099-B could be wrong or blank. Other common headaches include missing wash sale adjustments and basis errors from corporate actions.

If you invest across several brokerages and exchanges, you'll get multiple 1099-Bs. Pulling them all together into one clear tax picture is one of the trickier parts of investment tax reporting—especially when wash sales span across accounts.