What Is 1099-B Reporting and When Do You Need to Know About It?
If you've sold investments—stocks, mutual funds, bonds, or cryptocurrency—you may receive a Form 1099-B from your brokerage or financial institution. This form reports your investment sales activity to both you and the IRS. Understanding what it is and how it works helps you file taxes accurately and avoid costly mistakes.
What 1099-B Actually Reports 📋
A 1099-B is an information return that summarizes the proceeds from sales of securities and other investments you've sold during the tax year. Your broker or investment platform is required to file it with the IRS and send you a copy by January 31st of the following year.
The form captures key details about each transaction:
- The security sold (name and identification number)
- The sale date and quantity
- Your proceeds (the amount you received before fees or adjustments)
- Whether the sale was short-term or long-term (holding period matters for tax rates)
The "proceeds" reported are not your profit or loss—they're simply the gross amount you received when you sold. This is an important distinction because the IRS uses this figure as a starting point for tracking capital gains or losses.
Who Gets a 1099-B and When
You'll receive a 1099-B if:
- You sold securities through a brokerage account, retirement advisor, or online investment platform
- You traded mutual funds or ETFs
- You liquidated stocks, bonds, or options
- You sold cryptocurrency through a regulated exchange or broker
- You received proceeds from a dividend reinvestment plan (DRIP) sale
You will not receive a 1099-B for simple dividend or interest income, or for securities you still own (only sales trigger reporting).
How 1099-B Connects to Your Tax Return
The information on your 1099-B feeds into Schedule D (Capital Gains and Losses), which is where you report investment profits and losses on your tax return. Here's the flow:
- Your broker reports proceeds to the IRS on Form 1099-B
- You receive a copy and use it to calculate your actual gain or loss
- You report those gains or losses on Schedule D
- The IRS compares what you report to what your broker reported
This cross-check is why accuracy matters. If there's a mismatch, you may receive a notice from the IRS asking for clarification.
The Key Variables That Affect Your Reporting
Your situation determines how much of this form you'll actually use:
| Factor | Impact |
|---|---|
| Number of transactions | More sales = more line items to track and reconcile |
| Holding period | Whether gains are short-term (taxed as ordinary income) or long-term (lower rates) |
| Cost basis tracking | Whether your broker has your original purchase price on file; gaps require your own records |
| Tax-loss harvesting | If you're using losses to offset gains, accuracy is essential |
| Account type | Retirement accounts (401k, IRA) don't generate 1099-Bs; only taxable accounts do |
Common Issues With 1099-B Reporting
Cost basis mismatches are the most frequent problem. Your broker reports the sale proceeds, but they may not have complete or accurate records of what you originally paid. If you bought shares over time, reinvested dividends, or transferred securities from another broker, the cost basis reported might be incomplete or incorrect.
Multiple brokers complicate things. If you've traded through different platforms over the years, you'll receive multiple 1099-Bs. You must manually consolidate them for your tax return.
Wash sales create another layer. If you sold a security at a loss and bought a "substantially identical" one within 30 days before or after, that loss is disallowed for the current year—but 1099-B doesn't always catch this. You need to flag it yourself.
Cryptocurrency sales are sometimes misreported or incompletely reported, depending on the exchange's systems. Verify the accuracy yourself.
What You Need to Do With Your 1099-B
When you receive it:
- Verify the data matches your records. Check the number of shares sold, sale dates, and proceeds amounts.
- Gather your original cost basis (what you paid for each security). Your broker should have this, but confirm it.
- Calculate your actual gain or loss by subtracting cost basis from proceeds. This is your gain or loss—not the proceeds alone.
- Flag any discrepancies with your broker and request a corrected form (they'll issue a 1099-B Correction) if needed.
- Report on Schedule D using your corrected figures, even if they differ from what the 1099-B shows. Include an explanation if there's a significant gap.
When You Should Seek Help
This process is straightforward if you have a small number of simple transactions and your broker has complete cost basis data. It becomes complex—and the stakes climb—if you:
- Made dozens or hundreds of trades in a year
- Have missing or uncertain cost basis records
- Realized substantial gains or losses
- Used multiple brokers over time
- Engaged in tax-loss harvesting or wash sales
A tax professional or accountant can verify your 1099-B accuracy, reconcile multi-broker activity, and ensure your Schedule D is correct. This guidance is especially valuable if you expect to owe additional tax or claim significant losses.
The bottom line: a 1099-B is a tracking tool and IRS compliance document. Your responsibility is to verify it's accurate and report your actual gains and losses—not just the proceeds your broker reported.
