# Year-End ISO Exercise Calculator: Exercise Before December 31? | OptionsAhoy

> Exercise ISOs before December 31 or wait until January? See this year's federal AMT crossover, a multi-year exercise schedule, and the deadlines that follow. Free, no signup.

Markdown twin of https://optionsahoy.com/tools/iso-year-end (canonical). More for agents: https://optionsahoy.com/llms.txt

# Exercise ISOs before December 31, or wait?

The alternative minimum tax (AMT) is counted one calendar year at a time, and your crossover resets on January 1. See how much you can exercise this year before federal AMT applies, a multi-year schedule for the rest, and the deadlines that follow.

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Year-end checklist

## Before December 31

The calculator below shows your federal crossover for this year : the most ISO bargain element you can add this year before the federal alternative minimum tax (AMT) applies. It also plans a multi-year exercise schedule, where Year 1 is this year .

1. Use this year's real income. Include your year-end bonus and every RSU vest still due in this year . Income moves your crossover, and not always the way you would expect: in the 24% federal bracket and below, more income lowers it.
2. Get the exercise recorded by December 31. The date that counts is Box 2 of Form 3921, and administrators can take days to process an exercise. Ask for the year-end cutoff. Early-exercising unvested shares? The AMT then follows the vesting date unless you make the election within the transfer.
3. Past the crossover? Spread it. The crossover resets on January 1, so exercising up to it in this year and continuing in January keeps more of the exercise under it. The schedule below plans the longer version.
4. Have the cash, on time. AMT is owed in cash even if you sell nothing . Estimated tax is owed in installments, so one January payment can leave earlier quarters short. Extra withholding before year-end counts as paid evenly through the year, and the fourth-quarter estimate for this year is due in mid-January .
5. Know the same-year sale. Selling the shares in the same calendar year removes the AMT adjustment for them. The gain is then ordinary income, but never more than the bargain element, and a sale at a loss creates none. The sale has to happen by December 31 too.
6. Private company? Ask whether a new 409A valuation is coming. Exercising before or after it changes your bargain element.
7. Count the clock and the credit. A sale taxed at long-term rates needs more than a year after exercise and two after grant, and AMT on shares you keep generally comes back later as a credit.

[The full year-end checklist, with sources and a worked example →](https://optionsahoy.com/learn/iso-exercise-before-year-end)

## Your grant

pre-IPO? leave blank — enter price + growth manually ISO shares Strike price $ Current price $ Horizon 3 yrs Annual growth 10% Volatility drag 20% Cash return 5.0% Tax inputs Filing status State Annual income $ Prior AMT credit $ If you itemize: state and local taxes $ Schedule A, line 7. The 2026 deduction is capped at $40,400, less above $505,000 of income.

## Grant timeline

Apr 30, 2025 Left the company No: still employed For long-term capital gains treatment on the eventual sale, ISO shares need to be held until **Apr 30, 2027** (2 years from grant) *and* at least 1 year from exercise. Tranches sold before either deadline are disqualifying dispositions, taxed as ordinary income on the bargain element. The optimizer accounts for both treatments per tranche based on hold periods at horizon. **Want to see the whole picture?** Try [OptionsAhoy's beta](https://optionsahoy.com/?_=tool-amt-iso-explainer-inline): it optimizes ISOs alongside your entire portfolio, and you pick the goal: Max Value, Max Cash, or Min Total Tax. Net final value at year  3 sale — optimized plan

$226,772

After-tax dollars at end of year  3 , net of all federal + state taxes through the sale.

This year: exercise 2,492 shares (of 10,000 total).

= $489,421 gross gain at sale − $153,905 federal + state LTCG − $108,743 AMT premium above baseline regular tax (time-valued)

AMT premium for exercising: $105,649 (on top of $230,496 regular tax across the horizon)

Optimized plan keeps $55,350 more than lump-sum , $896 more than even split.

Federal AMT crossover this year: 914 shares ( $41,138 bargain element). Above that, each additional share this year adds federal AMT.

Estimates only. Not financial advice.

### Net final value by year

Running tally: NTV from shares exercised through year y, minus AMT premium paid through year y. The last year matches the plan's headline NTV. Hover a year for plan totals.

Lump-sum Even split Optimized Optimized exercise schedule You pay the higher of **Regular tax** and **Tentative AMT** per jurisdiction, then subtract **Credit recovered**. The result is **Net tax**. Hover any number for the bracket-by-bracket breakdown.

| Year | Shares | Bargain | Regular tax | Tentative AMT | AMT premium | Credit recovered | Net tax | Net value |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | 2,492 | $112,140 | $76,832 | $96,306 | $19,334 | — | $96,166 | $66,236 |
| 2 | 2,594 | $120,053 | $76,832 | $99,214 | $22,242 | — | $99,074 | $132,431 |
| 3 | 4,914 | $233,880 | $76,832 | $141,046 | $64,074 | — | $140,906 | $226,772 |

### Federal AMT credit

Earned

$94,302

Recovered

$0

Remaining

$94,302

The AMT credit only recovers in years where regular tax *exceeds* AMT — typically a year with no ISO exercise. Every year in this schedule has bargain element, so AMT exceeds regular tax in every year and the credit carries forward untouched. Try a longer horizon or fewer total shares to introduce a recovery year.

### Plan comparison

Net value at the end of your hold horizon.

Lump-sum

All in Year 1

$171,423

− $55,350

Even split

Equal shares each year

$225,877

− $896

Optimized

Tax-aware schedule

$226,772

Highest

Estimates only. Excludes disqualifying dispositions, NSOs, multi-state moves, and AMT preferences other than ISO bargain elements. Long-term capital gains tax assumes a qualifying disposition (ISO held ≥1 yr from exercise and ≥2 yr from grant); state LTCG follows ordinary brackets except where the state grants preferential treatment (HI, ND, SC, WI, AR, NM) or has a dedicated LTCG-only tax (WA). Assumes you are within the $100K ISO limit (any portion of an annual ISO grant whose FMV at grant exceeds $100K is treated as NSO from the start, §422(d)). State AMT figures are 2025 (next-year values published in late 2026). Not financial advice.

QSBS note. If your shares qualify (typically pre-IPO C-corp grants held 5+ years), a federal rule lets you exclude up to $10M of gain on a future sale from federal tax. That single rule shifts exercise-timing math more than AMT does. (This is §1202 “qualified small-business stock”.) Modeled in beta, not here.

You timed one exercise around December 31. The beta plans every grant across every year: ISOs, NSOs, RSU vests, hedges, and taxes in one multi-year plan.

Related calculators: [Multi-Year ISO Exercise Schedule Calculator](https://optionsahoy.com/tools/amt-iso?_=related-iso-year-end) · [NSO Exercise Calculator](https://optionsahoy.com/tools/nso?_=related-iso-year-end)

## What this calculates

- This year's federal alternative minimum tax (AMT) crossover: the most ISO bargain element you can add in the current tax year before federal AMT applies.
- A multi-year exercise schedule, since the crossover resets every January 1.
- Federal AMT plus state AMT for CA, CO, CT, and MN, and AMT credit recovery in later years.
- The days left in the tax year, the fourth-quarter estimated payment date, and the filing deadline, from your own calendar date.

Uses one income figure for every year; if next year's income will differ (a job change, a sabbatical), later years are approximate. Every year uses 2026 tax tables. The crossover is federal: in a state with its own AMT, state AMT can start below it. It does not know your plan administrator's cutoff, which can fall before December 31.

[Read the deep dive: Should you exercise ISOs before December 31? The 2026 year-end checklist →](https://optionsahoy.com/learn/iso-exercise-before-year-end)

## Methodology

Optimization. The same engine as the Multi-Year ISO Exercise Schedule Calculator. It computes this year’s federal alternative minimum tax (AMT) crossover from your income and filing status, then the multi-year exercise schedule with the highest expected after-tax value, with federal and state AMT and credit recovery. The deadlines in the checklist above it follow the Internal Revenue Code rule that a due date on a weekend or legal holiday moves to the next business day. The search is deterministic: the same inputs on the same date return the same answer, so the recommendation is verifiable.

Tax-code coverage. Relevant federal code (ordinary brackets, long-term capital gains, AMT with credit recovery, FICA, Net Investment Income Tax) plus each state's own return for all 50 states and DC (starting income, deductions, exemptions, surtaxes, LTCG treatment). State AMT modeled for CA, CO, CT, MN . Brackets reflect IRS Rev. Proc. 2025-32 and the One Big Beautiful Bill Act (OBBBA) provisions for tax year 2026. Validated against 870+ unit tests covering bracket math, AMT credit recovery, state conformity, and the optimizer's search path.

Why use an optimizer rather than asking an LLM to do the math: a benchmark of five frontier large language models on the same multi-year ISO problem found that all 15 trials overstated the after-tax result of their own proposed schedule by 2x to 20x ([HackerNoon write-up](https://hackernoon.com/but-can-it-do-taxes-though-why-you-shouldnt-trust-chatbots-with-tax-optimization-math)).

AI assistant integration

## Use this from ChatGPT, Claude, Cursor, or VS Code

Ask your agent:

> “ I have 5,000 vested ISOs at a $2 strike, FMV $22, and $200,000 of taxable income. Should I exercise before December 31 or split it with January? ”

With the OptionsAhoy MCP installed, your agent calls amt_iso_optimize and returns the same after-tax answer this calculator computes.

## December 31 is one deadline. A Plan covers every year.

OptionsAhoy plans your full equity portfolio: every ISO, NSO, RSU vest, hedge, and sale, across bullish, neutral, and bearish scenarios. Free during Beta.