Form 8949: reporting 1099-B sales box by box
Form 8949 is the IRS form taxpayers use to list each sale or exchange of a capital asset and reconcile it with the Form 1099-B, 1099-DA or 1099-S they received. Its totals flow to Schedule D, and columns (f) and (g) carry adjustments such as wash sales.
“Use Form 8949 to reconcile amounts that were reported to you and the IRS on Form 1099-B or 1099-S (or substitute statement) with the amounts you report on your return.” IRS, About Form 8949
Who has to file Form 8949, and which box applies?
Form 8949 is filed with Schedule D by any taxpayer that sold or exchanged a capital asset, including individuals, estates, trusts, partnerships, S corporations and corporations, according to the Instructions for Form 8949 (2025). The form reconciles what a broker reported on Form 1099-B, Form 1099-DA or Form 1099-S with what the return reports. Proceeds from the form always go in column (d), and when the form shows basis was reported to the IRS, that basis always goes in column (e). Any correction runs through columns (f) and (g).
Each Part I or Part II page carries one checkbox, and only transactions of that type go on that page. For 2025 the instructions add boxes G to L for digital asset transactions reported on Form 1099-DA, and boxes C and F can no longer be used for digital assets. Exception 1 lets a taxpayer skip Form 8949 for sales where basis was reported to the IRS and nothing needs adjusting, entering totals directly on Schedule D line 1a or 8a.
| Form 8949 box | Holding period | What goes there | Schedule D line |
|---|---|---|---|
| A (G for digital assets) | Short term, Part I | Basis shown and reported to the IRS | 1b |
| B (H) | Short term, Part I | Basis not shown, or shown but not reported to the IRS | 2 |
| C (I) | Short term, Part I | No Form 1099-B or 1099-DA received | 3 |
| D (J) | Long term, Part II | Basis shown and reported to the IRS | 8b |
| E (K) | Long term, Part II | Basis not shown, or shown but not reported to the IRS | 9 |
| F (L) | Long term, Part II | No Form 1099-B or 1099-DA received | 10 |
Where does each Form 1099-B box go on Form 8949?
Every numbered box on a 2025 Form 1099-B that feeds Form 8949 maps to one column or one checkbox. Boxes 1a to 1e fill columns (a) to (e), box 1f and box 1g become adjustments in column (g) with codes D and W, and boxes 2, 5 and 12 decide which Part and which checkbox the sale belongs on. The broker's “Applicable checkbox on Form 8949” entry (code A, B, D, E or X) is a hint, and code X means the broker doesn't know the holding period, so the preparer uses the client's records.
| Form 1099-B box | What it shows | Form 8949 |
|---|---|---|
| 1a | Description of property | Column (a) |
| 1b | Date acquired (may be blank if box 5 is checked) | Column (b), or “VARIOUS” |
| 1c | Date sold or disposed of | Column (c) |
| 1d | Proceeds | Column (d) |
| 1e | Cost or other basis | Column (e); an error is fixed with code B, not by editing the basis on a box A or D row |
| 1f | Accrued market discount | Code D in (f), worksheet amount in (g) |
| 1g | Wash sale loss disallowed | Code W in (f), positive amount in (g) |
| 2 | Short-term, long-term or Ordinary | Part I or Part II; code T if the type is wrong |
| 3 | Collectibles or QOF | Collectibles take code C with -0- in (g) |
| 5 | Noncovered security | Box B or box E |
| 12 | Basis reported to the IRS | Box A or box D |
Box 4 backup withholding goes on the return as tax withheld, and boxes 8 to 11 for regulated futures and section 1256 contracts go to Form 6781, not Form 8949, per the 2025 recipient instructions.
How do Form 8949 adjustment codes work?
Form 8949 column (h) is column (d) minus column (e), combined with any adjustment in column (g), and column (f) holds the code that explains the adjustment. The Instructions for Form 8949 (2025) require codes in alphabetical order with no spaces (for example “BOQ”) and a single net amount in column (g) when more than one code applies. Negative adjustments go in parentheses.
Code B has two treatments. On a box A or box D row, where basis was reported to the IRS, the preparer keeps the broker's basis in column (e) and enters the correction in column (g) using the Worksheet for Basis Adjustments. On a box B or box E row, the preparer enters the correct basis in column (e) and -0- in column (g). Code W is always a positive amount equal to the disallowed loss. Code E covers selling expenses or option premiums the form doesn't reflect, and code M marks a summary row under Exception 2.
| Code | Use it when | Column (g) |
|---|---|---|
| B | Basis in box 1e is wrong | Correction (box A or D rows); -0- on box B or E rows |
| D | Box 1f shows accrued market discount | Worksheet amount |
| E | Selling expenses or option premiums aren't reflected | Negative for costs paid |
| L | Nondeductible loss other than a wash sale | Positive |
| M | Several transactions reported on one row | -0- unless another code applies |
| T | Box 2 shows the wrong type of gain or loss | -0- if nothing else changes |
| W | Wash sale loss is disallowed | Positive, the disallowed loss |
| O | Any other adjustment | As needed |
What does a Form 8949 calculation look like?
For example, Priya's 2025 consolidated Form 1099-B shows four sales. ABC: 100 shares held four months, box 12 checked, proceeds $5,000, basis $6,200, box 1g $400. LMN: 40 shares from a nonqualified stock option exercised two months earlier, box 12 checked, proceeds $3,100, box 1e $2,000, and her W-2 included $1,000 of exercise income, so correct basis is $3,000. XYZ: 50 shares bought in 2019, box 12 checked, proceeds $9,000, basis $4,000, no adjustments. DEF: 200 shares bought in 2008, box 5 checked, proceeds $12,000, box 1e blank, and her records show $7,500 of basis.
| Step | Form line | Gain (loss) |
|---|---|---|
| ABC: $5,000 minus $6,200, plus $400 code W | 8949 Part I, box A, (h) | ($800) |
| LMN: $3,100 minus $2,000, minus $1,000 code B | 8949 Part I, box A, (h) | $100 |
| Box A totals carried to Schedule D | Sch. D 1b | ($700) |
| XYZ: no adjustment, Exception 1 | Sch. D 8a | $5,000 |
| DEF: $12,000 minus $7,500 from client records | 8949 Part II, box E; Sch. D 9 | $4,500 |
| Net long-term gain | Sch. D 15 | $9,500 |
| Net capital gain | Sch. D 16 | $8,800 |
Priya's $400 wash sale loss isn't lost. It is added to the basis of the replacement ABC shares, which a broker reports in box 1e when it sells them. Leaving out the code B line on LMN would overstate her gain by $1,000.
What do reviewers check on Form 8949?
A reviewer checking Form 8949 confirms six items, each tied to the Instructions for Form 8949 (2025) or the Schedule D instructions. The broker statement is the first document to pull, because column (d) proceeds and, for covered securities, column (e) basis have to match it line for line, and any difference has to be explained by a code in column (f). The second is the client's own basis record for anything in box B or box E, since nothing on the 1099-B supports that number.
Gains on Form 8949 also feed Form 8960 line 5a for clients above the net investment income tax threshold. For how box 1e and box 1g are built, see Form 1099-B box 1e and wash sales.
Every line checked against the documents the client sent
Filed reads the client's Forms 1099-B, 1099-DA and 1099-S, W-2s and basis records, then checks every row of Form 8949 against them. Anything that doesn't tie comes back as a review item with a citation to the source.
Book a demoForm 1099-B shows $1,240 in box 1g for 300 sh. QRS, but Form 8949, Part I (box A) reports the full $1,240 loss with columns (f) and (g) blank. Confirm whether code W and a $1,240 adjustment belong on this row.
Common questions
Do I have to file Form 8949 if all my basis was reported to the IRS?
Form 8949 isn't required for sales where Form 1099-B shows basis was reported to the IRS, boxes 1f and 1g are blank, the Ordinary box isn't checked and no other adjustment is needed. Under Exception 1, those totals go directly on Schedule D line 1a (short term) or line 8a (long term). Collectibles and QOF deferrals don't qualify.
What does code W mean on Form 8949?
Code W on Form 8949 means part or all of a loss is disallowed under the wash sale rules. The disallowed amount goes in column (g) as a positive number, usually the figure in Form 1099-B box 1g. If the correct amount differs from the broker's figure, the preparer enters the correct amount and explains a smaller figure in an attached statement.
What is the difference between box A and box B on Form 8949?
Box A and box B on Form 8949 both hold short-term sales reported on Form 1099-B. Box A is for sales where the broker reported basis to the IRS, shown by a checked box 12. Box B is for sales where basis wasn't reported, usually noncovered securities with box 5 checked. Boxes D and E are the long-term equivalents.