Leaving Mercury? Plan your 90-day ISO window
Calculator · free · no signup · pre-IPOMercury 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 11, 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: $81,526 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
$19,042
Recovered
$19,042
Remaining
$0
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 Mercury
Mercury is a privately held Fintech company, incorporated in Delaware and headquartered in San Francisco, CA.
Last reported secondary-market price: $17.72 per share (as of 2026-06-11). Your own 409A may differ.
$5B+ Apr 2026.
Equity grants at Mercury typically include incentive stock options (ISOs) and non-qualified stock options (NSOs).
Mercury Technologies Inc., commonly known as simply Mercury, is an American fintech company that provides banking services to start-up companies and small businesses. The company is not a bank, but works with banking service providers to provide bank accounts and other financial services. The company was founded in 2017 in San Francisco, California. As of May 2026, Mercury has a $5.2 billion valuation.
Source: Wikipedia (CC BY-SA 4.0)
Immad Akhund, Max Tagher, and Jason Zhang founded Mercury in 2017 to give startups and small businesses a banking experience built for companies that move fast. Mercury offers FDIC-insured checking and savings accounts, corporate cards, and treasury products through a software interface rather than a branch. In March 2025 the company raised a $300 million Series C led by Sequoia Capital at a $3.5 billion valuation, doubling its 2021 Series B valuation. Mercury processed $156 billion in payment volume in 2024.
Sources: en.wikipedia.org · businesswire.com
OptionsAhoy is an independent tool and is not affiliated with, endorsed by, or sponsored by Mercury.
If you are leaving Mercury 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 Mercury with 5,000 vested ISOs at a $5.32 strike, with the last reported price at $17.72, exercising all of them inside the 90-day window puts a $62,000 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 $17,360 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 Mercury tools → · Use the generic Post-Termination ISO Exercise Calculator for any company.
Mercury equity questions
- I left Mercury. 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 Mercury'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 Mercury grant ISOs, NSOs, or RSUs?
- Equity compensation at Mercury 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 Mercury 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 Mercury 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 Mercury equity alongside hedging, vesting, and de-concentration, across bullish, neutral, and bearish market scenarios. Free during beta.