Vesting stock is taxed like salary, but payroll withholds it at flat supplemental rates. If your marginal rate is higher — for most people with several grants, it is — the difference is due in April. HoldBack tracks your grants and computes that number, with every line of the math visible.
Computed by the same engine the product runs — 2026 federal and CA tables, standard deduction, RSU income priced as your last-stacked dollars. Withholding beyond the vests themselves isn't modelled here. Create a free account to compute it from your actual grants and keep it current.
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Type them in, upload the grant PDF, or import your broker's CSV. Documents are read into a draft — never straight into your numbers.
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Every extracted value sits beside the exact words it came from, read independently by two models, with disagreements flagged for you to settle. You confirm; only then does it count.
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The vest ledger shows what's real and what's scheduled. The tax screen shows what April costs — and every line of how it was computed.
| Date | Grant | Units × price | Value |
|---|---|---|---|
| 2026Feb 1 | ACME · New hire 2024cliff | 1,200 × $168.25 | $201,900.00 |
| May 1 | ACME · New hire 2024 | 300 × $175.10 | $52,530.00 |
today · Jul 25 | |||
| Aug 1 | ACME · New hire 2024 | 300 × $182.10ᵉ | $54,630.00 |
| Nov 1 | ACME · New hire 2024 | 300 × $182.10ᵉ | $54,630.00 |
No Plaid, no account linking, no scraping. Your data arrives by typing, file upload, or CSV — nothing else can.
Uploaded grant documents are deleted after you confirm the import, unless you choose to keep them.
Document reading runs through the Claude API under commercial data-processing terms — not a consumer product's terms.
Every tax figure comes from versioned public tax tables and arithmetic you can inspect line by line. Models read documents; they never do the math.
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Complete and useful on its own. No countdown, no nagging.