You sold RSU shares and your broker shows proceeds on Form 1099-B but basis is wrong or zero. You want the step-by-step calculation tying vest fair market value to cost basis so you do not pay capital gains tax on income already taxed as wages.
Start here
What you need before using this
- for the sale (proceeds and reported basis).
- confirmation for the lot sold (date, shares, per share).
- for the year showing wages in Box 1.
- Broker supplemental tax lot detail if provided.
- Trade confirm showing sale date and proceeds per share.
Basis rules follow IRS guidance for compensation stock. Broker reporting errors are common — retain vest confirmations.
Why this happens
is ordinary wage income when shares deliver — that amount is your investment basis in those shares per IRS Pub. 525 wage and property rules.
Brokers record acquisitions from open market purchases — delivery from employer plans often lacks basis in data feeds.
Box 1e basis $0 does not mean basis is zero — it means the broker did not report employer wage .
calculation per lot: shares sold × per share at for that lot.
Multiple vests create multiple lots with different dates and — match sale lot to correct confirmation.
sales at may appear on with basis equal to if broker reports plan correctly — still reconcile to .
Form 8949 adjustment code B or W may apply when basis reported to IRS differs from correct basis — follow form instructions for filing year.
Long-term vs short-term gain depends on holding period from to sale date — basis calculation is separate from holding period.
Wash sale rules generally do not apply to wages the same way as purchased shares — see wash sale guide for repurchase scenarios.
Corporate actions — splits, spinoffs — adjust share count and per-share basis per broker and IRS guidance.
Fees and commissions reduce proceeds and may increase basis depending on reporting — check detail.
Gift or transfer of shares after carries donee basis rules — this guide focuses on original employee .
Box 1 includes wages — basis should not exceed already counted in wages for those shares.
Lost confirmation: equity portal export, pay stub archive, or amended broker basis request — see portal export guide.
Software imports literally unless you enter adjustment — calculation must be done before filing.
What to check
- and on confirmation for lot sold.
- Shares sold match lot on .
- Calculated basis = shares × .
- Proceeds on minus basis ≈ /loss.
- year Box 1 includes that in wages.
- Broker supplemental shows plan transfer if available.
- Holding period from to sale for LTCG vs STCG.
- Form 8949 adjustment if broker basis wrong.
Using sale proceeds as taxable gain because 1099-B basis is zero
What to check in your documents
- with proceeds and reported basis boxes.
- confirmation PDF for matching lot.
- for year.
- Broker adjustment worksheet if provided.
- Form 8949 draft showing basis adjustment.
50 shares vested at $100, sold at $110
Illustration only, not your tax situation.
Questions people ask
- What is cost basis for RSU shares?
- Generally per share at when shares delivered and taxed as wages — total basis is shares × that .
- How to calculate RSU cost basis?
- Find confirmation for the lot sold, multiply by shares sold, subtract from proceeds on Form 8949.
- Restricted stock units cost basis same as RSU?
- Standard delivery at uses . Restricted stock with 83(b) may differ — see 83(b) guides.
- Why is my cost basis zero on 1099-B?
- Brokers often omit employer wage . You supply correct basis from records — see why basis zero guide.
- Cost basis on sell-to-cover at vest?
- Shares sold for have basis equal to ; gain/loss may be minimal if sold same day at .
- Multiple vests — which basis for sale?
- Match sold lot to specific confirmation (FIFO or plan lot ID). Each lot has its own .
- W-2 and cost basis double count?
- reports wages; basis prevents taxing same again as . You are not taxed twice on same dollars when basis is correct.
- Cost basis calculator vs manual calculation?
- calculator walks proceeds minus . Manual math is the same — calculator helps organize lots.
- Amend if I used zero basis?
- Yes — Form 1040-X with corrected Schedule D if you overstated gain. See amend return basis guide.
- Which forms show RSU basis inputs?
- confirmation and for wage ; for proceeds; Form 8949 for reported gain.
When to get help from a tax pro
- Corporate action adjusted shares and basis unclear.
- Sale lot cannot be matched to any confirmation.
- Gift or estate transfer of shares after .
- IRS notice on sale with disputed basis.
Related calculators
- RSU Cost Basis Calculator
Cost basis on sold RSUs usually ties back to vest FMV already taxed as wages — this tool helps you model that link.
- 1099-B RSU Adjustment Helper
Structured helper for RSU 1099-B problems — zero basis, duplicate wage reporting, and supplemental plan lot details.
- RSU Sale Tax Calculator
Estimate capital gain tax on RSU share sales using vest FMV as basis — separate from vest wage tax already on your W-2.
Related pages
- Why Is My RSU Cost Basis Zero?
Zero basis on 1099-B usually means the broker did not link your vest wage income — not that tax was skipped.
- How to Adjust RSU Cost Basis
Basis adjustments connect vest wage income to later sales — document FMV from vest records.
- Are RSUs Taxed Twice?
Vest income and later sales can both show up on tax forms — that is not always double tax on the same dollars.
- RSU Supplemental Stock Plan Lot Detail Explained
Supplemental lot detail reports often hold the vest price you need when 1099-B basis is wrong.
- How to Read an RSU Vest Confirmation
Vest confirmation FMV is your wage income and future sale basis — save the PDF even when net shares look smaller after withholding.
- Schedule D for RSU Sales
RSU sales go on Form 8949 and Schedule D with basis tied to vest wage income — separate from W-2 vest reporting but connected through cost basis.
Sources and notes
Primary tax claims on this page are supported by the official and secondary sources below. Broker and software links describe reporting mechanics — confirm rules against IRS or state guidance.
Vest FMV as wage income and basis for later RSU sales; broker $0 basis reporting.
- IRS Publication 525 — Taxable and Nontaxable Income
Internal Revenue Service · Official
Covers compensation income from stock-based pay, including restricted property under section 83.
- About Form 1099-B — Proceeds from Broker and Barter Exchange Transactions
Internal Revenue Service · Official
Broker reporting of sales proceeds and basis; basis on 1099-B may be incomplete for equity-compensation shares.
- Filing taxes for restricted stock, RSUs, or performance awards (tax guide PDF)
Fidelity Stock Plan Services · Brokerage explainer
Explains W-2 vest income, 1099-B with $0 basis, supplemental adjusted cost basis, and Form 8949 reporting.
For learning, not filing
VestingTax.com is not a CPA firm or tax preparer. Grants, employers, and states all differ. Use the cited IRS and state sources above, your own documents, and a qualified tax professional before you make decisions from this guide.