Leaving Quantinuum Inc.? Plan your 90-day ISO window
Calculator · free · no signup · pre-IPOQuantinuum Inc. is pre-IPO. Left with vested ISOs? Model the 90-day exercise-or-forfeit decision and its AMT cost at any valuation: current 409A or an expected exit price.
Beta · invite-only · AlphaLatitude Inc. · Free Tools
Your grant
Seeded from secondary-market data, as of Jun 3, 2026
Tax inputs
Grant timeline
Recommended exercise quantity
Exercise all 10,000
With 10%/yr expected growth over the 3-yr hold, every share's expected after-tax gain exceeds its marginal AMT cost. Net value: $205,590 at horizon.
Net after-tax value vs. shares exercised
Each point is the expected after-tax NPV at your hold horizon if you exercise that many shares now and let the rest expire.
Year-by-year tax breakdown
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.
| 1 | 10,000 | |||
| 2 | 0 | |||
| 3 | 0 |
Federal AMT credit
Earned
$162,654
Recovered
$29,764
Remaining
$132,890
The AMT credit only recovers in years where regular tax exceeds AMT — typically a year with no ISO exercise. It carries forward indefinitely (Form 8801) and applies in any future tax year where regular tax exceeds AMT.
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 solved the exercise window. The beta plans what comes after it: the new shares, your remaining equity, hedges, and taxes in one multi-year plan.
Request beta access →About Quantinuum Inc.
Quantinuum Inc. is a privately held Cloud/SaaS company, incorporated in Delaware and headquartered in Broomfield, CO. S-1 filed May 26, 2026.
Last reported secondary-market price: $60 per share (as of 2026-06-03). Your own 409A may differ.
Equity grants at Quantinuum Inc. typically include incentive stock options (ISOs) and non-qualified stock options (NSOs).
Quantinuum formed in 2021 when Honeywell merged its Honeywell Quantum Solutions hardware division with Cambridge Quantum Computing, a software firm founded by Ilyas Khan in 2014. Headquartered in Broomfield, Colorado with a second base in Cambridge, UK, the company builds trapped-ion quantum computers (H-Series hardware) and paired software tools covering cybersecurity, quantum chemistry, and machine learning. In September 2025 it raised $600 million at a $10 billion pre-money valuation, with investors including NVIDIA's NVentures and JPMorgan Chase. It filed an S-1 with the SEC on May 26, 2026, targeting a Nasdaq listing under the ticker QNT.
Sources: sec.gov · thequantuminsider.com
Equity comp at Quantinuum Inc.
- Quantinuum is a Honeywell majority-owned spinoff (approximately 49% post-IPO voting power retained by Honeywell) with an Up-C corporate structure (a dual-entity arrangement where the public company holds membership units in an operating LLC rather than owning assets directly). The 2023 Equity Incentive Plan includes a one-time liquidity award worth $25 million in equity securities that vests 25% per year over four years from the IPO effective date, conditioned on continued employment. Standard restricted share grants vest 25% per year over four years. Change-in-control acceleration is double-trigger, meaning it requires both a qualifying corporate transaction and either a qualifying termination or a continued-service condition. Section 83(b) elections (a tax form filed within 30 days of a restricted share grant, allowing the recipient to pay income tax at grant-date value rather than waiting for shares to vest) are the sole responsibility of the participant to file.
- Recent share-sale events (industry term: tender offers):
- Jan 2024: $5B implied valuation, led by JPMorgan Chase · honeywell.com
- Sep 2025: $10B implied valuation, led by Honeywell and co-investors including NVIDIA NVentures, Quanta Computer, Mitsui, and Amgen · honeywell.com
Researched 2026-05-28.
OptionsAhoy is an independent tool and is not affiliated with, endorsed by, or sponsored by Quantinuum Inc..
If you are leaving Quantinuum Inc. with vested incentive stock options (ISOs), most stock plans give you 90 days from departure to exercise or forfeit them. The calculator works at any valuation: enter your strike and the current 409A fair market value (FMV) or an expected exit price. It computes your window deadline, the alternative minimum tax (AMT) cost of exercising in full, and the partial-exercise share count that maximizes expected after-tax value.
Example: leaving Quantinuum Inc. with 5,000 vested ISOs at a $18 strike, with the last reported price at $60, exercising all of them inside the 90-day window puts a $210,000 bargain element into one tax year. Above the 2026 federal AMT exemption ($88,100 single, $137,000 married joint), the 28% AMT rate adds roughly $58,800 on top of regular tax before any state AMT (CA, CO, CT, MN). Exercising fewer shares lowers that bill at the cost of forfeiting the rest; the calculator above finds the count that maximizes expected after-tax value for your exact figures.
All Quantinuum Inc. tools → · Use the generic Post-Termination ISO Exercise Calculator for any company.
Quantinuum Inc. equity questions
- I left Quantinuum Inc.. How long do I have to exercise my ISOs?
- Most stock plans give you 90 days from your departure date to exercise vested incentive stock options (ISOs); unexercised options are forfeited when the window closes. Tax law is slightly wider: ISO treatment requires you to have been an employee within 3 months of exercise (Internal Revenue Code Section 422(a)(2)), so options exercised under an employer-extended window are taxed as non-qualified stock options (NSOs). Check your grant agreement for Quantinuum Inc.'s exact terms. The calculator above computes your deadline from your departure date, the alternative minimum tax (AMT) cost of exercising, and the share count that maximizes after-tax value.
- Does Quantinuum Inc. grant ISOs, NSOs, or RSUs?
- Equity compensation at Quantinuum Inc. typically takes the form of incentive stock options (ISOs) and non-qualified stock options (NSOs). Incentive stock options can trigger the alternative minimum tax (AMT) when you exercise.
- Are Quantinuum Inc. shares eligible for QSBS?
- They might be. Qualified small business stock (QSBS) under Internal Revenue Code Section 1202 can exclude federal tax on much of the gain when shares were acquired at original issuance from a C-corporation while its gross assets were under $50 million, and held at least five years. Whether your Quantinuum Inc. shares qualify turns on when you acquired them and the company's asset size at that time.
One piece of the puzzle.
OptionsAhoy plans your Quantinuum Inc. equity alongside hedging, vesting, and de-concentration, across bullish, neutral, and bearish market scenarios. Free during beta.