You fill out IRS Form 1099-B by reporting each sale or exchange of stocks, bonds, mutual funds, options, futures, commodities, cryptocurrency, or barter exchange property on a separate line, listing the description, dates, proceeds, cost basis, wash sale adjustments, and gain or loss, then transferring those totals to Form 8949 and Schedule D of your federal return. Brokers, barter exchanges, and certain digital asset platforms must issue the form to both the customer and the IRS by the deadlines set under IRC §6045, and recipients must reconcile every transaction on their tax return.
Missing or mismatched 1099-B data triggers automated CP2000 notices from the IRS Automated Underreporter program, and the agency processed over 4 million such notices in a single recent year, with proposed assessments averaging thousands of dollars per taxpayer per notice.
Here is what you will learn in this guide:
- 📋 How every box on Form 1099-B works, line by line, for stocks, options, futures, crypto, and barter trades
- 💰 How to translate your 1099-B numbers into Form 8949 and Schedule D entries without triggering an IRS mismatch
- ⚖️ How federal rules under IRC §6045 and the new digital asset broker regulations interact with state conformity quirks
- 🚨 How to avoid wash sale traps, basis errors, and the seven most expensive 1099-B mistakes
- 🧾 How named taxpayers handle real-world scenarios involving short-term gains, long-term losses, crypto swaps, and barter income
What Is IRS Form 1099-B?
Form 1099-B is the information return brokers and barter exchanges file with the IRS to report proceeds from the sale or exchange of securities, commodities, regulated futures contracts, foreign currency contracts, forward contracts, debt instruments, options, and securities futures contracts. Brokers also use the form to report cost basis on covered securities under the Emergency Economic Stabilization Act of 2008 cost-basis reporting rules. Barter exchanges report the fair market value of property or services exchanged through them on the same form.
The form exists because Congress wanted to close the tax gap between income earned and income reported. The plain-English idea is that when a broker knows how much you sold for, the IRS knows too, so the system stops relying on honor-based reporting. The consequence of ignoring a 1099-B is direct: the IRS computer matches the form against your return, and any unreported amount becomes a proposed deficiency plus interest and accuracy penalties under IRC §6662. A common misconception is that small trades fall below a reporting threshold, but unlike Form 1099-MISC, there is no de minimis dollar floor for 1099-B securities reporting.
A real-world example helps. Maria sells 50 shares of Apple stock through Fidelity for $9,500. Fidelity issues a 1099-B showing $9,500 in proceeds and $4,000 in cost basis. Maria must report a $5,500 long-term capital gain on her return, even though no one mailed her a check labeled income.
Who Issues Form 1099-B
Brokers defined under Treasury Regulation §1.6045-1 issue the form, which includes stockbrokers, mutual fund companies, dealers in commodities, and clearinghouses. Barter exchanges with more than 100 members also issue the form under IRC §6045(c)(3). Beginning January 1, 2025, the final digital asset regulations require custodial digital asset brokers like Coinbase and Kraken to issue Form 1099-DA for crypto sales, while many platforms continued issuing 1099-B for 2024 transactions. The consequence of failing to issue a required form is a penalty under IRC §6721, which can reach $310 per form for 2025 filings, with no maximum if the failure is intentional.
Who Receives Form 1099-B
You receive a 1099-B if you are the customer, member, or client of a reporting entity and you closed a position, sold a security, or completed a barter trade during the year. The form must reach you by February 15 of the year following the transaction, which is later than most 1099 deadlines because Congress gave brokers extra time to compute basis. The consequence of not getting your copy is not an excuse to skip reporting, since the IRS still receives its copy and will match against your return.
A common misconception is that if I did not receive a 1099-B, I owe no tax. The actual rule under IRC §61 is that all gains from property sales are taxable regardless of whether a form is issued.
Boxes on Form 1099-B Explained
Every box on Form 1099-B carries a specific meaning, and each one feeds a specific line on your return. The official Instructions for Form 1099-B walk through each field, but they read like an engineering manual. Below is a plain-English breakdown with consequences and a real example for each box.
Box 1a Through 1g: The Core Transaction Data
Box 1a shows the description of the property, such as 100 sh. AAPL. Box 1b shows the date the security was acquired, which determines short-term versus long-term treatment under IRC §1222. Box 1c shows the date sold or disposed of, which fixes the tax year. Box 1d shows gross proceeds, meaning the amount you received before commissions if Box 6 is checked gross, or net of commissions if Box 6 is checked net. Box 1e shows the cost or other basis, which is what you paid plus adjustments under IRC §1012 and IRC §1016. Box 1f shows the accrued market discount on debt instruments, and Box 1g shows the wash sale loss disallowed under IRC §1091.
The consequence of misreading these boxes is real. If you treat a date in Box 1b as the sale date, you flip a long-term gain into a short-term one and pay ordinary income rates up to 37% instead of the long-term capital gain rate of 0%, 15%, or 20% under IRC §1(h).
A common misconception is that Box 1e is always correct. For non-covered securities (those acquired before 2011 for stock, before 2012 for mutual funds, or before 2014 for bonds), the broker is not required to report basis, and Box 1e may be blank or wrong, leaving the burden on you to track it.
Box 2: Short-Term or Long-Term
Box 2 tells you whether the gain or loss is short-term, long-term, or ordinary. Short-term means held one year or less. Long-term means held more than one year. Ordinary applies to certain debt instruments and contingent payment notes. The consequence is enormous because long-term capital gains receive preferential rates under IRC §1(h), while short-term gains are taxed at ordinary rates.
For example, David held a stock for 364 days and sold for a $20,000 gain. Because Box 2 reads short-term, David pays at his 32% bracket, costing $6,400. Had he waited two more days, the same gain would have cost him 15%, or $3,000.
Box 3: Type of Asset and Box 4: Federal Tax Withheld
Box 3 identifies the kind of asset, with codes for covered securities, non-covered securities, collectibles, and digital assets after 2024. Box 4 shows federal income tax withheld under the backup withholding rules of IRC §3406, currently 24%. The consequence of ignoring Box 4 is that you forfeit a credit you already paid, since backup withholding flows to Line 25b of Form 1040. A common misconception is that backup withholding is a final tax. It is not. It is a prepayment, refundable when you file.
Boxes 5 Through 7: Non-Covered, Reported, and Loss Disallowed
Box 5 is checked when the security is non-covered, meaning the broker is not required to report basis. Box 6 indicates whether proceeds are gross or net of commissions and option premiums. Box 7 is checked when the loss is not allowed because of a wash sale under IRC §1091, a related-party sale under IRC §267, or a loss on collectibles taxed at 28%.
The consequence of overlooking Box 5 is filing with a wrong basis the IRS does not have on file, which produces no automatic mismatch but exposes you on audit. The consequence of missing Box 7 is claiming a deduction the law forbids, which is a clear accuracy penalty trigger.
Boxes 8 Through 11: Regulated Futures and Section 1256 Contracts
These boxes apply to Section 1256 contracts, which include regulated futures, foreign currency contracts, non-equity options, dealer equity options, and dealer securities futures contracts. Box 8 shows the profit or loss realized in the current year on closed contracts. Box 9 shows the unrealized profit or loss on open contracts at year-end. Box 10 shows the unrealized profit or loss on open contracts at the start of the year. Box 11 shows the aggregate profit or loss on contracts for the year, which is the figure that flows to Form 6781.
The plain-English rule is that Section 1256 contracts are marked to market every December 31, and the gain or loss is automatically split 60% long-term and 40% short-term, regardless of holding period. The consequence of ignoring this rule is double-counting open positions year after year. A common misconception is that you can defer the gain by not closing the contract, but the mark-to-market rule overrides intent.
Boxes 12 Through 15: Basis Reporting and State Tax
Box 12 is checked if the basis was reported to the IRS, which affects which category of Form 8949 you use. Box 13 shows the bartering income for barter exchanges. Boxes 14 through 16 capture state tax withheld, the state, and the state identification number. The consequence of mismatching Box 12 to the wrong Form 8949 box is automatic IRS correspondence, because the agency cross-references reported and not-reported buckets.
Step-by-Step: How to Use a 1099-B on Your Tax Return
The work moves in three stages. First, you receive the 1099-B from each broker. Second, you transfer each transaction to Form 8949. Third, you total Form 8949 by category and bring those totals onto Schedule D, then to Form 1040 Line 7.
Step 1: Gather Every 1099-B
Confirm you have a form from every broker, mutual fund, barter exchange, and digital asset platform you used during the year. The consequence of missing one is an automated CP2000 notice issued 12 to 18 months after filing. A real example is Priya, who used three brokerage apps in one year and forgot a small Robinhood account. Robinhood reported $1,200 of unreported proceeds, and Priya received a $410 proposed assessment plus interest 14 months later.
Step 2: Sort Transactions Into Form 8949 Categories
Form 8949 has six possible boxes. Box A is short-term covered with basis reported to the IRS. Box B is short-term covered with basis not reported. Box C is short-term not reported on a 1099-B at all. Box D is long-term covered with basis reported. Box E is long-term covered with basis not reported. Box F is long-term not reported on any 1099-B. The consequence of misclassifying is an IRS letter asking you to amend.
Step 3: Enter Each Trade on Form 8949
For every line, fill in the description, dates, proceeds, basis, adjustment code if any, adjustment amount, and gain or loss. Common adjustment codes include W for wash sale, D for market discount, and B for incorrect basis. A real example: James sold 100 shares of Tesla at a $3,000 loss, then bought back 100 shares 20 days later. He must enter code W and a $3,000 positive adjustment, eliminating the loss in the current year and adding it to the basis of the replacement shares under IRC §1091(d).
Step 4: Total Form 8949 and Carry to Schedule D
Add columns by box, then move totals to Schedule D. Schedule D combines all short-term and all long-term results, applies any capital loss carryover from IRC §1212, and produces a single number for Form 1040 Line 7. The consequence of skipping Schedule D is that capital loss carryovers vanish, since the carryover worksheet only updates when Schedule D is filed.
Three Common Scenarios With Tables
Scenarios make the rules concrete. Here are three of the most common patterns.
Scenario 1: Short-Term Stock Gain
| Trade Detail | Tax Outcome |
|---|---|
| Bought 100 shares NVDA at $400 on March 1 | Basis is $40,000 entered in Box 1e |
| Sold 100 shares NVDA at $550 on November 1 | Proceeds are $55,000 entered in Box 1d |
| Held 245 days, less than one year | Box 2 marks short-term, taxed at ordinary rates |
| $15,000 gain reported on Form 8949 Box A | Carried to Schedule D Part I |
Scenario 2: Long-Term Crypto Loss
| Trade Detail | Tax Outcome |
|---|---|
| Bought 1 BTC at $60,000 on January 5, 2023 | Basis is $60,000, tracked by taxpayer if not on 1099-B |
| Sold 1 BTC at $42,000 on June 10, 2025 | Proceeds are $42,000 |
| Held over one year | Long-term loss of $18,000 |
| Loss offsets long-term gains, then $3,000 against ordinary income | Excess carries forward under IRC §1212 |
Scenario 3: Wash Sale on a Mutual Fund
| Trade Detail | Tax Outcome |
|---|---|
| Sold 200 shares of XYZ Fund at a $4,000 loss on December 15 | Loss tentatively $4,000 |
| Bought 200 shares of XYZ Fund on December 28 | Triggers wash sale under IRC §1091 |
| Box 1g reports $4,000 disallowed loss | Code W on Form 8949 |
| Disallowed loss adds to basis of replacement shares | Loss recovered when replacement shares are sold |
Concrete Examples With Named Taxpayers
Sofia is a software engineer in Austin who sold 500 shares of Microsoft on August 12, 2025, for $215,000. She bought the shares on January 4, 2018, for $90,000. Her broker issues a 1099-B with $215,000 in Box 1d, $90,000 in Box 1e, Box 2 marked long-term, and Box 12 checked because basis was reported. Sofia enters the trade on Form 8949 Box D with a $125,000 long-term gain, which carries to Schedule D and is taxed at 15% federal because her taxable income falls in the long-term capital gain bracket under IRC §1(h).
Marcus runs a small landscaping business in Atlanta and is a member of a registered barter exchange. He provided $8,000 of lawn services in exchange for office equipment. The barter exchange reports $8,000 in Box 13 of his 1099-B. Marcus must report the $8,000 as ordinary business income on Schedule C, not as a capital gain, because services are ordinary income under IRC §61. The consequence of treating it as capital gain is an accuracy penalty.
Aisha day-trades E-mini S&P 500 futures, which are Section 1256 contracts. Her 1099-B shows Box 11 aggregate profit of $50,000. She files Form 6781, which automatically splits the $50,000 into $30,000 long-term and $20,000 short-term, even though she never held a contract more than a few hours. This 60/40 rule under IRC §1256 saves her thousands compared to ordinary treatment.
Mistakes to Avoid When Filing With a 1099-B
Mistakes are expensive, and the IRS catches most of them automatically.
- Ignoring a 1099-B because the amount seems small leads to a CP2000 notice and accuracy penalties under IRC §6662.
- Trusting Box 1e on non-covered securities causes overstated or understated basis, and the IRS will not flag it but an audit will.
- Forgetting wash sale code W on Form 8949 produces a disallowed loss that the IRS computer matches against Box 1g and rejects.
- Mixing short-term and long-term totals on Schedule D collapses the preferential rate benefit and overstates tax.
- Skipping Form 6781 for Section 1256 contracts loses the 60/40 split and pushes everything to ordinary rates.
- Treating barter income from Box 13 as capital gain instead of ordinary income triggers self-employment tax adjustments and penalties.
- Failing to track basis for crypto bought before broker reporting started leaves you with a zero basis and a 100% taxable proceeds figure.
- Reporting proceeds on Form 8949 net of commissions when Box 6 says gross causes a mismatch.
- Filing without reconciling all 1099-Bs to your trade log misses corrected forms that brokers commonly issue in March or April.
- Ignoring state tax withheld in Boxes 14 through 16 leaves a refundable state credit on the table.
Do’s and Don’ts of 1099-B Reporting
These rules separate clean filings from costly ones.
Do’s
- Do reconcile every 1099-B to your own brokerage statements, because brokers issue corrected forms more often than any other 1099 type.
- Do use Form 8949 to enter each transaction line by line when adjustments apply, because summary reporting is allowed only when no adjustments are needed.
- Do track basis on non-covered securities yourself, because the broker is not required to report it and your records are the only proof.
- Do file Form 6781 when Section 1256 contracts appear, because the 60/40 rule is mandatory and beneficial.
- Do report digital asset transactions even if no 1099-B was issued, because IRC §61 treats every disposition as taxable.
Don’ts
- Don’t assume a missing form means no tax liability, because the IRS receives its copy regardless.
- Don’t claim a wash sale loss in the current year, because IRC §1091 defers it to the basis of replacement shares.
- Don’t mix asset categories on the same Form 8949 line, because the IRS matching system separates covered and non-covered buckets.
- Don’t rely on the broker’s gain/loss summary alone, because it does not include trades from other brokers or wash sales across accounts.
- Don’t ignore corrected 1099-Bs received after filing, because the IRS will match the corrected version and propose a deficiency.
Pros and Cons of Receiving a 1099-B
Understanding both sides helps you plan.
Pros
- The form gives you a paper trail of every taxable disposition, which simplifies audit defense.
- Cost basis on covered securities is calculated for you, reducing record-keeping burden.
- Backup withholding shown in Box 4 is a refundable prepayment that lowers the balance due.
- Wash sale tracking inside one account is automated, sparing you manual identification.
- Section 1256 mark-to-market figures are pre-computed, easing Form 6781 preparation.
Cons
- Brokers do not coordinate wash sales across accounts, so cross-broker losses can be wrongly claimed.
- Basis on non-covered securities is your responsibility, and old records may be hard to find.
- Corrected 1099-Bs arrive after filing, often forcing an amended return.
- Box 1d may be reported gross or net of commissions, creating reconciliation work.
- Barter exchange income in Box 13 is ordinary income but is delivered on a form most people associate with capital gains, causing classification errors.
State Conformity Nuances
Most states begin with federal capital gain and loss figures from Schedule D, but they apply their own rules on top. California does not conform to federal qualified small business stock exclusion under IRC §1202 for sales after 2013 in the same way as federal law, so a 1099-B sale that is federally tax-free may be fully taxable in California. New York conforms broadly but has special rules for nonresidents trading through New York brokers. New Hampshire imposes an interest and dividends tax that historically reached certain capital gain distributions, with the tax phasing out by 2027. The consequence of ignoring state nuance is a state notice that arrives months after the federal return clears.
A common misconception is that a state with no income tax means no reporting at all. Even in Texas or Florida, federal reporting is unaffected, and trades in tax-deferred accounts can still produce federal income through unrelated business taxable income.
Court Rulings and Enforcement Trends
The Tax Court has repeatedly enforced strict reading of basis reporting. In Hoang v. Commissioner, T.C. Memo 2014-217, the court rejected a taxpayer’s attempt to claim a higher basis than the 1099-B reported without documentation. In Adams Challenge (UK) Ltd. v. Commissioner, the court emphasized that information returns create a strong presumption of correctness. The IRS has also expanded the J5 international tax enforcement group to chase unreported crypto, leveraging 1099-B and 1099-DA data.
The plain-English consequence is that the IRS treats 1099-B figures as the starting point. You can rebut them, but you need records. A common misconception is that I will fix it later is fine. The Tax Court routinely rejects late-produced records when they conflict with timely-filed information returns.
Penalties for Filers and Recipients
Brokers face penalties under IRC §6721 for failing to file correct information returns and under IRC §6722 for failing to furnish correct payee statements. Each penalty runs up to $310 per form for 2025 returns, doubled for intentional disregard, with no cap when willful. Recipients face accuracy penalties of 20% under IRC §6662 and, in fraud cases, 75% under IRC §6663.
A real example: a broker that issued 5,000 incorrect 1099-Bs could face $1,550,000 in penalties for incorrect filings plus another $1,550,000 for incorrect payee statements, before any willfulness uplift. Recipients who omit a $50,000 gain face a $10,000 accuracy penalty plus interest. The consequence is that both sides of the form have a strong incentive to get it right.
Digital Assets and the New 1099-DA
Effective January 1, 2025, custodial digital asset brokers must use Form 1099-DA for sales of digital assets, replacing 1099-B for those transactions, while basis reporting phases in starting January 1, 2026. The plain-English idea is that crypto exchanges now report like stockbrokers. The consequence of using the wrong form is a mismatched return, since IRS systems route 1099-DA data into a separate matching pipeline. A common misconception is that DeFi platforms must issue 1099-DA. Treasury narrowed the final DeFi rule and Congress has since acted on related provisions, so non-custodial platforms are largely outside current reporting.
Frequently Asked Questions
Do I have to report a 1099-B if I had a net loss?
Yes. Every 1099-B transaction must appear on Form 8949 and Schedule D, even at a loss, because losses offset gains and up to $3,000 of ordinary income annually under IRC §1211.
Can I ignore a 1099-B for under $20?
No. There is no de minimis threshold for 1099-B reporting, and the IRS Automated Underreporter program matches every form regardless of size, often issuing notices for amounts under $100.
Is cryptocurrency reported on Form 1099-B in 2025?
No. Beginning January 1, 2025, custodial digital asset brokers report crypto sales on Form 1099-DA, not 1099-B, although some platforms still issued 1099-B for 2024 transactions during the transition.
Do I owe self-employment tax on barter income from Box 13?
Yes. Barter income for services rendered is ordinary trade or business income reportable on Schedule C and subject to self-employment tax under IRC §1401.
Can I claim a wash sale loss in the same year?
No. IRC §1091 disallows the loss in the current year, defers it to the basis of the replacement shares, and Form 8949 requires code W with a positive adjustment.
Are 1099-B losses limited?
Yes. Capital losses offset capital gains in full, but only $3,000 of net loss per year ($1,500 if married filing separately) offsets ordinary income, with the remainder carried forward under IRC §1212.
Does the broker calculate basis correctly for older shares?
No. For non-covered securities acquired before basis reporting began, the broker may leave Box 1e blank, and you must reconstruct basis from your own records.
Is short-term gain on a 1099-B taxed differently from long-term gain?
Yes. Short-term gains are taxed at ordinary rates up to 37%, while long-term gains receive preferential rates of 0%, 15%, or 20% under IRC §1(h).
Do I need to attach the 1099-B to my tax return?
No. You enter the data on Form 8949 and Schedule D, and you keep the 1099-B in your records, although you must attach a statement if you summary-report and the broker did not provide IRS-approved totals.
Can the IRS audit me if my Form 8949 matches the 1099-B?
Yes. Matching reduces audit risk but does not eliminate it, because the IRS can still examine basis on non-covered securities, wash sale tracking across accounts, and classification of barter income.
Does a corrected 1099-B require an amended return?
Yes. If the corrected form changes your tax, you must file Form 1040-X within three years of the original due date to claim a refund or before the IRS proposes a deficiency.
Are foreign brokers required to issue Form 1099-B?
No. Non-U.S. brokers without a U.S. trade or business are generally not subject to IRC §6045, but you still owe U.S. tax on the trades and must self-report on Form 8949.
Related reading
- How to Fill Out IRS Form 8949 (w/Examples) + FAQs
- Where to Enter 1099-B in TaxSlayer? (w/Examples) + FAQs
- How to Fill Out IRS Form 1040 – Schedule D + FAQs
- How to Fill Out IRS Form 1099-A (w/Examples) + FAQs
- How to Fill Out IRS Form 1099-NEC (w/Examples) + FAQs
- How to Fill Out IRS Form 1099-S (w/Examples) + FAQs
- How to Fill Out IRS Form 8300 (w/Examples) + FAQs