⚠ Educational only.
TaxPlain does not provide tax, legal, or financial advice. Always consult a qualified tax professional about your specific situation.
What this form is
Form 8949 is the IRS form used to report sales and exchanges of capital assets — things like stocks, ETFs, cryptocurrency, real estate, and other investments. It tells the IRS exactly what you sold, when you bought it, what you paid for it, and whether you made or lost money.
Think of Form 8949 as the detailed receipt behind your investment taxes. Schedule D gives the summary totals, but Form 8949 shows the transaction-by-transaction breakdown that supports those numbers.
Who must file
✓ Usually Required
Anyone who sold investments during the year and must report capital gains or losses on their tax return. This includes stocks, crypto, mutual funds, ETFs, options, and many property sales.
↑ Common Triggers
Receiving a Form 1099-B from a brokerage, selling cryptocurrency, cashing out investment accounts, or selling property that increased or decreased in value.
📅 Filing deadline
Form 8949 is attached to your annual Form 1040 tax return and follows the same deadline — usually April 15. If you file an extension, Form 8949 extends automatically with your return.
What each section covers
Breaking down Form 8949
The form is split into short-term and long-term investment sales. The IRS taxes them differently, so the form separates them clearly.
Part I — Short-term transactions — Investments you owned for 1 year or less before selling. Usually taxed at ordinary income tax rates.
Part II — Long-term transactions — Investments held longer than 1 year. Usually qualify for lower long-term capital gains tax rates.
Description of property — The name of what you sold (Apple stock, Bitcoin, rental property, etc.).
Date acquired — When you originally bought or received the asset.
Date sold — When you sold or exchanged it.
Proceeds — How much money you received from the sale.
Cost basis — What you originally paid for the asset, including certain fees.
Adjustment codes — Corrections for wash sales, missing basis information, or other IRS-required adjustments.
Gain or loss — The final profit or loss after subtracting basis and adjustments from sale proceeds.
Where the information comes from
Most people complete Form 8949 using information from Form 1099-B sent by their brokerage or crypto platform. That form reports what was sold and often includes cost basis information.
However, broker records are not always complete — especially for cryptocurrency, transferred accounts, or older investments. You are legally responsible for accurate numbers even if the brokerage reports something incorrectly.
✓ Common Sources
1099-B forms, crypto exchange records, brokerage statements, employee stock plan records, and real estate closing documents.
⚠ IRS Red Flag
Leaving out sales reported to the IRS on a 1099-B is one of the fastest ways to trigger an IRS notice. The IRS computer system cross-checks these automatically.
Common mistakes to avoid
⚠ Missing Cost Basis
If your basis is missing or wrong, the IRS may assume your basis is zero — making your taxable gain appear much larger than it actually was.
⚠ Ignoring Crypto Trades
Swapping one cryptocurrency for another is usually taxable even if you never converted back to cash. Many taxpayers incorrectly assume crypto-to-crypto trades are tax free.
⚠ Wash Sale Rules
Selling an investment at a loss and rebuying it within 30 days can disallow the deduction temporarily. Brokerages often flag this, but not always across multiple accounts.
⚠ Wrong Holding Period
Misclassifying long-term and short-term gains can cause incorrect tax calculations. Holding period rules start the day after purchase.
What to do right now
If you sold investments this year, gather every 1099-B, crypto statement, and brokerage report before filing. Double-check cost basis numbers carefully — especially for transferred accounts and cryptocurrency. If your return involves heavy trading, crypto activity, employee stock plans, or large investment gains, tax software can become confusing quickly. A CPA or enrolled agent may prevent expensive reporting mistakes and IRS notices.
Questions to ask your tax professional
01
Did my brokerage report accurate cost basis information to the IRS?
02
Do any of my transactions trigger wash sale adjustments?
03
Are my crypto transactions fully reported and categorized correctly?
04
Can any capital losses reduce my ordinary income this year?
05
Should I carry unused capital losses forward into future tax years?
06
Did any of my investment sales qualify for lower long-term capital gains tax rates?
Frequently asked questions
What is the difference between Form 8949 and Schedule D?
Form 8949 lists each individual transaction in detail. Schedule D summarizes the totals from Form 8949 and calculates your final capital gain or loss for the year.
Do I need Form 8949 for cryptocurrency?
Usually yes. Selling crypto, trading one coin for another, spending crypto, or converting crypto to cash are all commonly taxable events that belong on Form 8949.
What happens if I forget to report a stock sale?
If the brokerage reported the sale to the IRS on a 1099-B, the IRS will often detect the mismatch automatically and mail you a notice proposing additional tax, penalties, and interest.
Can investment losses lower my taxes?
Yes. Capital losses first offset capital gains. If losses exceed gains, up to $3,000 per year can usually reduce ordinary income, with extra losses carried forward into future years.
Do I need to attach brokerage statements?
Usually no if you e-file and properly complete Form 8949. However, you should keep all supporting records in case the IRS asks for proof later.