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The biggest trouble on a Form 1099-B is almost never the proceeds figure. It is the blank cost basis. Securities transferred in from another custodian years ago often arrive with Box 1e empty or Box 5 marked noncovered, and until someone reconstructs that basis from old trade confirmations, Form 8949 cannot be finished and Schedule D cannot be touched.
The quiet rule worth copying into a process is to flag those blanks in January rather than discovering them in March. Wash sale adjustments in Box 1g have to flow exactly to Form 8949, or a mismatch invites a CP2000 notice. Brokers must furnish recipient copies by February 15, 2026, file on paper by February 28, and e-file is mandatory once you reach 10 or more information returns in aggregate.
Key Takeaways
- Form 1099-B is issued by brokers and barter exchanges to report proceeds from the sale or exchange of securities, regulated futures contracts, foreign currency contracts, and barter transactions – recipients use it to complete Schedule D and Form 8949.
- Brokers are required to file; taxpayers receive a copy (Copy B) to report capital gains and losses on their federal return.
- Brokers must furnish recipient copies by February 15, 2026 (the later furnishing deadline that applies to Form 1099-B generally, including when bundled into a consolidated reporting statement, and rolling to the next business day if it falls on a weekend or holiday) and file with the IRS by March 31 if filing electronically, or February 28 on paper.
- The single biggest pitfall is missing or incorrect cost basis – especially for securities transferred between brokers after the 2011 covered security rules took effect.
- Wash sale adjustments reported in Box 1g must flow exactly to Form 8949; mismatches trigger CP2000 notices.
- Quick rule you can copy into your SOP: flag any 1099-B where Box 1e (cost basis) is blank or Box 5 (noncovered) is checked – those transactions require manual basis research before Form 8949 preparation can begin.
What Form 1099-B Is and When to Use It
Form 1099-B, Proceeds from Broker and Barter Exchange Transactions, is an information return that brokers, dealers, and barter exchanges use to report gross proceeds and, where applicable, cost basis information to both the IRS and the taxpayer. The form captures every sale, exchange, or redemption of a security during the calendar year, along with any regulated futures or foreign currency contracts closed in the same period.
The recipient – your client – uses Copy B to prepare Form 8949, Sales and Other Dispositions of Capital Assets, which feeds directly into Schedule D. From my side of the desk, Form 1099-B is the starting document for every capital gains conversation. If it’s wrong, everything downstream is wrong.
Who Is Required to File
The filing obligation falls on the broker or barter exchange, not the taxpayer. A “broker” for this purpose includes any person who regularly provides a market for, or acts as an intermediary in, the purchase or sale of securities. That covers traditional brokerage firms, digital asset exchanges (for certain transactions), mutual fund companies, and barter exchange networks.
Barter exchanges issue 1099-B to members who swap property or services through the exchange. The fair market value of goods or services received in a barter transaction is ordinary income, reported on the same form that reports securities proceeds.
What Triggers a 1099-B
A 1099-B is required whenever a broker effects the sale of a covered or noncovered security, closes a regulated futures contract, closes a Section 1256 foreign currency contract, or processes a barter exchange transaction. Redemptions of mutual fund shares, sales of debt instruments, and stock option exercises that result in a sale are all reportable. Transactions that do not require a 1099-B include sales by exempt recipients (corporations, generally), certain short-term debt under 6 months, and transactions in qualified opportunity zone funds under certain conditions.
Covered vs. Noncovered Securities
The IRS phased in cost basis reporting requirements starting in 2011 for equities, 2012 for mutual funds and ETFs, and 2014 for fixed income and options. Securities acquired on or after these effective dates are “covered,” meaning brokers must report adjusted basis to the IRS. Securities acquired before those dates are “noncovered” – the broker reports gross proceeds but not basis. This distinction is the root cause of most basis reconstruction work we do each tax season.
How to Complete Form 1099-B
Each sale of a security gets its own row on the 1099-B. For taxpayers with active brokerage accounts, the broker’s consolidated statement may contain hundreds of rows, each mapping to a separate Form 8949 line. Understanding the box structure helps you catch errors before they reach the return.
| Box / Field | What It Contains | Practitioner Note |
|---|---|---|
| Box 1a – Description of property | Number of shares and name of security sold | Verify lot count against trade confirmations if client reports fractional shares |
| Box 1b – Date acquired | Date securities were originally purchased | Multiple lots may be aggregated; confirm holding period for long/short term classification |
| Box 1c – Date sold or disposed | Trade date of the sale | Use trade date, not settlement date, for tax reporting |
| Box 1d – Proceeds | Gross proceeds from the sale | May be net of commissions depending on broker; note if “net proceeds” box is checked |
| Box 1e – Cost or other basis | Adjusted cost basis of the security | Blank for noncovered securities; must be researched manually |
| Box 1f – Accrued market discount | Discount on debt instruments previously recognized as ordinary income | Adjusts basis; ensure it flows correctly to 8949 adjustment column |
| Box 1g – Wash sale loss disallowed | Amount of loss disallowed under wash sale rules | Must be entered as an adjustment (code W) on Form 8949; easy to miss |
| Box 2 – Type of gain or loss | Short-term, long-term, or ordinary | Ordinary loss applies to certain Section 1244 stock and options; flag these |
| Box 3 – Check if basis reported to IRS | Checked if IRS received cost basis (covered security) | If unchecked, transaction goes on Part III of Form 8949 |
| Box 4 – Federal income tax withheld | Backup withholding amount, if applicable | Required if client had a B-notice and did not certify TIN |
| Box 5 – Noncovered security | Checked if this is a noncovered security | When checked, broker is not reporting basis to IRS; you must reconstruct |
| Box 6 – Reported to IRS: Gross proceeds / Net proceeds | Whether proceeds are gross or net of commissions | Affects basis calculation; confirm with client’s trade statements |
| Box 7 – Loss not allowed based on amount in box 1d | Checked when gain or loss cannot be determined | Rare; occurs in certain mutual fund liquidation scenarios |
| Boxes 8–11 – Profit/loss on futures | Regulated futures and Section 1256 contract data | Section 1256 contracts are 60% long-term / 40% short-term; mark-to-market at year-end |
| Boxes 12–14 – State tax information | State identification number, income, and withholding | Some states require separate reconciliation; verify against state return |
How Form 8949 Maps to Schedule D
Every 1099-B transaction flows to Form 8949, grouped by category: Part I (short-term covered), Part II (long-term covered), and Part III (noncovered or with adjustments). The totals from 8949 feed directly to Schedule D. Any adjustment to the 1099-B amounts – wash sales, accrued market discount, basis corrections – requires entering an adjustment code in column (f) of Form 8949. Missing adjustment codes are a primary driver of CP2000 notices.
Barter Exchange Transactions
When a barter exchange issues a 1099-B, it reports the fair market value of the goods, services, or scrip the member received through the exchange (captured under the bartering amount code in the IRS record layout). The recipient must report the FMV of what they received as ordinary income on their return, typically on Schedule 1 or Schedule C, depending on whether the barter activity is part of a trade or business. Barter 1099-Bs are frequently overlooked by clients who treat them as non-taxable swaps – they are not.
Deadlines, Penalties, and Filing Requirements
| Requirement | Date / Threshold | Notes |
|---|---|---|
| Furnish Copy B to recipient (standard) | January 31 | Applies to most 1099-series statements, but Forms 1099-B and 1099-S are carved out of the January 31 rule and follow the later February furnishing deadline shown below, including when furnished as part of a consolidated reporting statement |
| Furnish Copy B to recipient (extended – brokers) | February 15, 2026 | Later furnishing deadline for Forms 1099-B and 1099-S, including consolidated brokerage statements; rolls to the next business day when February 15 falls on a weekend or holiday |
| Paper filing with IRS (Copy A) | February 28 | Use Form 1096 as transmittal cover sheet |
| Electronic filing with IRS (FIRE system; note FIRE is targeted for retirement after Tax Year 2025, with IRIS becoming the only intake system beginning with Filing Season 2027) | March 31 | Required if filing 10 or more information returns in aggregate |
| E-file threshold (mandatory) | 10 or more returns | Filers with 10+ information returns must e-file; applies per filer, not per form type |
| Extension for furnishing to recipient | Up to 30 days (Form 15397) | Request must be filed before original due date; IRS approval not automatic |
Penalty Structure
Penalties for failure to file or furnish correct 1099-Bs are tiered by how late the correction is made. Small businesses (average annual gross receipts ≤$5M for three prior years) have lower caps. Intentional disregard has no cap and carries a minimum penalty per return.
| Scenario | Penalty per Return | Annual Cap (Large Filer) |
|---|---|---|
| Filed/corrected within 30 days of due date | $60 | $683,000 |
| Filed/corrected after 30 days but by August 1 | $130 | $2,049,000 |
| Filed after August 1 or not at all | $340 | $4,098,500 |
| Intentional disregard | $680 (minimum) | No cap |
| Failure to furnish correct payee statement | Same tier structure | Separate penalty from filing penalty |
Extensions and Corrections
Brokers who need more time to furnish accurate consolidated statements to recipients may request a 30-day extension by submitting Form 15397 to the IRS before the original furnishing date. This is different from the already-extended February 15, 2026 furnishing deadline available under Treas. Reg. §1.6045-1. If an error is discovered after filing, file a corrected 1099-B as soon as possible – the correction window before the August 1 cliff matters significantly for penalty exposure.
Cost Basis Reporting Rules in Depth
The cost basis reporting rules introduced by the Energy Improvement and Extension Act of 2008 fundamentally changed how brokers and tax preparers interact on capital gain schedules. Before these rules, the broker reported gross proceeds and nothing more – basis reconstruction was entirely the taxpayer’s problem. Now, for covered securities, the broker must report adjusted basis and holding period to both the taxpayer and the IRS.
Default Accounting Methods and Client Elections
For equities, the default method is FIFO (first-in, first-out) unless the client has made a specific lot identification election with the broker. For mutual funds, the average cost (single category) method is often the default, though clients can elect specific identification. From my side of the desk, the most common surprise is discovering a client’s brokerage account defaulted to FIFO while their accountant had been calculating gains using specific ID. Those two methods rarely produce the same numbers, and reconciling them after the fact is painful.
Clients can change their accounting method prospectively, but once a lot has been sold, the method election for that specific lot is locked. Make it a practice to review the broker’s default method at the start of each relationship and document the client’s election – or lack thereof – in your permanent file.
Transferred Accounts and Basis Gaps
When a client moves an account from one broker to another, the transferring broker is required to send cost basis information to the receiving broker via a transfer statement (Form 1099-B copy B equivalent). In practice, the information transfer is often incomplete – particularly for assets held in kind, complex lot histories, or securities acquired before the covered security dates. The receiving broker may label these assets as “transferred as noncovered,” which pushes basis reconstruction back onto the taxpayer and their CPA.
Corporate Actions and Basis Adjustments
Stock splits, mergers, spin-offs, and return-of-capital distributions all affect cost basis. Brokers are required to adjust basis for covered securities following corporate actions, but the timing and accuracy of those adjustments vary. A stock split should halve the per-share basis, but I’ve seen brokers carry forward the pre-split basis on one lot and correctly adjust another – producing inconsistent 1099-B data across the same position. Checking the corporate action history against the broker’s reported basis is a step worth building into your review checklist for active traders and investors with legacy positions.
Wash Sale Rules and 1099-B Reporting
The wash sale rule under IRC §1091 disallows a loss on the sale of stock or securities if substantially identical stock or securities are purchased within 30 days before or after the sale. Brokers are required to track wash sales within the same account for covered securities and report the disallowed amount in Box 1g of Form 1099-B. What brokers are not required to do is track wash sales across multiple accounts held by the same taxpayer, or across a taxpayer’s IRA.
Cross-Account and IRA Wash Sale Exposure
This is one of the most frequently missed issues I see on returns involving active traders. A client sells a position at a loss in their individual taxable account and purchases substantially identical securities in their IRA within the wash sale window. The broker for the taxable account does not know about the IRA purchase. The 1099-B shows the full loss as unrestricted – but the loss is disallowed. Worse, the basis adjustment that would normally be added to the replacement shares cannot be applied to an IRA, so the loss is permanently lost. A conversation about investment activity across all accounts – not just the one producing the 1099-B – is a necessary part of tax prep for any client who is both active in taxable accounts and making IRA contributions or transactions.
How to Handle Partial Wash Sales
If a client sells 100 shares at a loss and repurchases only 60 shares within the window, only 60% of the loss is disallowed. The remaining 40% is deductible in the current year. Brokers should report this correctly, but errors occur. Verify that the wash sale amount in Box 1g is proportionate to the repurchase quantity when you see partial transactions. Small errors create big cleanup, especially when the same stock was traded in and out of a position multiple times across the tax year.
Digital Assets and Form 1099-B
The IRS treats cryptocurrency and other digital assets as property for federal tax purposes. Digital asset broker reporting now has its own form: Form 1099-DA, Digital Asset Proceeds From Broker Transactions, which custodial digital asset brokers are first required to use for 2025 transactions, with the first filings made in early 2026. Gross proceeds reporting applies to 2025 dispositions, and broker basis reporting phases in for digital assets acquired beginning in 2026. Crypto sales are not reported on Form 1099-B itself, so when a client trades on a custodial exchange you should expect a 1099-DA rather than a 1099-B, while decentralized and self-custody activity often still falls outside any broker-issued form.
For tax preparers, this means digital asset basis tracking often falls on the client and their accountant rather than the exchange. Tools like CoinTracker, Koinly, and TaxBit can export data in 8949-compatible format, but the underlying data quality depends entirely on how consistently the client tracked wallet activity across platforms. Any time digital assets are moved off-exchange – to hardware wallets, DeFi protocols, or other exchanges – the transaction history may be incomplete or entirely absent from any 1099 document.
Common Mistakes That Slow Things Down
Most 1099-B problems I see are not exotic basis questions – they are calendar and process slips on the filing side that surface long after the records are transmitted. Here are the ones that cost the most cleanup.
Practical Checklists You Can Reuse
These are copy-paste ready for your firm SOP library. Drop them into your workpaper templates and tick the boxes as you go – the page remembers your progress on each list.
1099-B Pre-File QC (broker or filer)
- Furnish recipient copies by February 15, 2026, not January 31, including any consolidated statements.
- Count all information returns across every form type; if the total is 10 or more, file electronically.
- File electronically with the IRS by March 31, 2026, or on paper by February 28, 2026 if you are under the threshold.
- Confirm each record points to the correct Form 8949 box: A or D for basis reported, B or E for basis not reported, X for an unknown holding period.
- Set the Noncovered Security Indicator only on noncovered lots.
- For aggregate transactions, leave Date Sold, Date Acquired, and the CUSIP number blank.
- Report losses with a leading minus sign, and never report a negative in the federal income tax withheld field (Amount Code 4).
Extensions and Corrections Control
- Request a 30-day IRS filing extension on Form 8809 before the due date if you cannot transmit on time.
- Request more time to furnish recipient statements on Form 15397, filed before the recipient due date; Form 8809 does not cover this.
- File any electronic-filing hardship waiver on Form 8508 at least 45 days before the return due date.
- File corrections through the same channel as the original return, electronically if it was filed electronically.
- Use corrected return indicator G for a one-transaction correction.
- File Missouri 1099-B reporting directly with the state; it left the Combined Federal/State Filing program for tax year 2025.
- Retain file copies three years, or four years when backup withholding was reported.
Preparer Intake Review (returns with a 1099-B)
- Wait for corrected or consolidated statements before finalizing returns with active brokerage accounts.
- Reconcile every 1099-B line to Form 8949 and carry the totals to Schedule D.
- Flag noncovered lots for basis reconstruction before the return goes to review.
- Check wash sale loss disallowed amounts and look for cross-account or IRA repurchases the broker cannot see.
- Confirm the broker's default lot accounting method matches the client's election on file.
Keep 1099-B Season From Stalling
Form 1099-B season runs on a calendar that trips up even experienced teams. Recipient copies are due February 15, 2026, the paper filing deadline with the IRS lands February 28, 2026, and the electronic deadline follows on March 31, 2026 (per IRS Publication 1220). Layer on the 10-return aggregate e-file mandate under Treasury Decision 9972 and the reality that brokers routinely issue corrected and consolidated statements well into March, and the production window compresses fast.
The teams that stay calm through it treat 1099-B as a structured data exercise, not a last-minute scramble. The volume is predictable and the failure points are known, so building the controls once means the same checklist carries every account through review.
- Reconcile each 1099-B line to Form 8949, grouping covered lots into boxes A and D and noncovered lots into boxes B and E before anything reaches Schedule D.
- Hold returns with active brokerage accounts until corrected and consolidated statements land, so a late basis revision does not force an amended return.
- Track the three separate deadlines – February 15, February 28, and March 31, 2026 – on one board, and file Form 8809 or Form 15397 early when an account will not be ready.
- Flag every noncovered lot and every wash sale loss disallowed amount for a second reviewer, since that is where cross-account exposure hides.
This is the kind of structured, deadline-driven production Accountably is built to absorb. Our trained, U.S.-led offshore teams run 1099-B reconciliation, Form 8949 mapping, and corrected-statement tracking inside your workflow with documented SOPs and turnaround SLAs, so capital gains work moves through review without the February crunch. See how our tax preparation services keep the season moving.
FAQs
What is the difference between a covered and noncovered security on Form 1099-B?
A covered security is one acquired after the IRS phase-in dates (2011 for equities, 2012 for mutual funds and ETFs, 2014 for fixed income and options), meaning the broker must report both gross proceeds and adjusted cost basis to the IRS. A noncovered security was acquired before those dates – the broker reports proceeds but not basis. When Box 5 is checked on the 1099-B, the transaction is noncovered, and the taxpayer (through their preparer) is responsible for reconstructing and reporting the correct basis on Form 8949.
Do I need to attach Form 1099-B to my tax return?
You do not attach the actual 1099-B to your federal return. Instead, you report the transactions on Form 8949 and carry the totals to Schedule D. If you are filing on paper and have many transactions, you may be able to attach a summary statement in lieu of individual 8949 lines, but the IRS preference is full transaction-level reporting on Form 8949 wherever possible.
What happens if my broker reports incorrect cost basis on Form 1099-B?
You can correct the error on Form 8949 by reporting the amount shown on the 1099-B in column (e), entering the correct basis, and using code B in column (f) to indicate the adjustment. The IRS reconciles the reported 1099-B amount against what you file, so the adjustment code is what signals that you are making a legitimate correction, not just reducing a taxable gain without explanation.
Are cryptocurrency sales reported on Form 1099-B?
Not on Form 1099-B itself. The IRS treats cryptocurrency as property, and dispositions are taxable events reportable on Form 8949 and Schedule D. Digital asset broker reporting now uses Form 1099-DA, which custodial digital asset brokers are first required to file for 2025 transactions, with the first filings in early 2026. So a custodial exchange will typically issue a 1099-DA rather than a 1099-B. Taxpayers must report all taxable crypto transactions regardless of whether they receive any form – the absence of a form does not eliminate the reporting obligation. Third-party crypto tax software can help generate Form 8949-compatible export files.
What is a wash sale and how does it affect my 1099-B?
A wash sale occurs when you sell a security at a loss and repurchase substantially identical securities within 30 days before or after the sale. The disallowed loss amount is reported in Box 1g of the 1099-B and must be entered as an adjustment with code W on Form 8949. The disallowed loss is added to the basis of the replacement shares. Brokers only track wash sales within the same account – cross-account and IRA repurchases are not captured on the 1099-B and must be identified manually.
When do brokers issue corrected Form 1099-Bs?
Brokers often issue corrected or amended 1099-Bs in February and March after discovering errors in corporate action adjustments, reclassifications of dividend income, or cost basis corrections. It is common practice to wait until mid-to-late March before filing returns for clients with active brokerage accounts, particularly those holding REITs, MLPs, or securities that received late-filed corporate action data. Always check for a “corrected” checkbox at the top of the form before treating a document as final.