What Happens to Your Stock Options When You Leave a Company?

When you leave a company, any stock options that have not yet vested are almost always forfeited on your last day, and you get a short window — commonly 90 days — to buy shares under the options that did vest before those expire too. That is the short version of what happens to stock options when you leave a company, and everything else follows from those two rules: the type of option, the reason you left, and the language of your specific plan determine how the details play out.

Unvested Options Disappear on Your Last Day

Most grants vest over four years with a one-year cliff: you earn nothing for the first year, then a portion each month or quarter after that. Anything not vested by your last day of work is canceled and returned to the company’s option pool.

This is automatic under nearly every equity plan. A representative SEC-filed employee stock option agreement puts it plainly: “Any unvested Options held by the Participant shall immediately be forfeited and canceled as of the date of termination of Participant’s employment.”¹ If you are a week away from a large vesting milestone when you give notice, that batch is gone unless your departure agreement says otherwise.

How Long You Have To Exercise Vested Options

Vested options are yours in the sense that you have earned the right to buy the shares at the strike price. You still have to actually buy them, and the clock starts on your last day.

Incentive Stock Options: The Three-Month Rule

Federal tax law gives incentive stock options (ISOs) favorable treatment only if you exercise within three months of your last day of employment. The statute requires that you were an employee “at all times during the period beginning on the date of the granting of the option and ending on the day 3 months before the date of such exercise.”² Miss the window and you can often still exercise, but the IRS reclassifies the transaction as a nonqualified exercise, which is taxed more heavily.

For that reason, most plans set the ISO exercise deadline at 90 days after departure. If you leave because of permanent disability, the three-month window stretches to one year.³

Nonqualified Stock Options: Whatever Your Plan Says

Nonqualified stock options (NSOs) have no statutory deadline. Your plan document sets the window, and it can run anywhere from 30 days to several years. There is always an outer limit: every grant has an overall expiration date (usually ten years from the grant date), and no post-termination window extends past that. Once either deadline passes, the right to buy those shares is gone permanently.

Death and Disability

Many plans give a longer window when a departure is caused by death or disability. A one-year extension is common. One SEC-filed agreement provides that in the event of death or disability, vested options expire “at the close of business at Company headquarters on the date one year after your termination date.”⁴ If an employee dies, the estate or a named beneficiary can exercise within that period.

Extended Windows

A number of technology companies now offer post-termination exercise periods well beyond 90 days, sometimes up to seven or ten years. These extended windows apply to NSOs, or to ISOs that convert to NSO tax treatment once the three-month mark passes. The extra time is useful, but the tax reclassification still happens on day 91 for anything originally granted as an ISO.

What Exercising Will Cost You in Taxes

Exercising is a taxable event, and the bill can be large enough to change your decision about whether to exercise at all.

Nonqualified Options

When you exercise an NSO, the difference between the current fair market value and your strike price — the spread — is taxed as ordinary income that year. Your former employer reports it as wages on your W-2 and withholds federal income and payroll taxes at exercise.⁵ Any additional gain between exercise and sale is a capital gain.

Incentive Stock Options and the AMT Trap

ISOs owe no regular federal income tax at exercise. The spread does count as an adjustment for the alternative minimum tax, though.⁵ For 2026, the AMT exemption is $90,100 for single filers and $140,200 for married couples filing jointly.⁶ A large ISO exercise at a company whose stock has appreciated substantially can push you well past those exemption levels, producing a real cash tax bill in a year when you have not sold anything.

To keep the full ISO tax benefit when you sell, you have to hold the shares for at least two years from the grant date and one year from the exercise date.² Selling earlier is called a disqualifying disposition: the spread at exercise gets reclassified as ordinary income, with any additional gain taxed as a capital gain.

How To Actually Exercise

Before you can buy the shares, pull three numbers from your original grant agreement or your company’s equity portal:

Your strike price per share.
The number of vested shares available to you.
Your exercise deadline.

Most companies handle the mechanics through an online platform. Some still require a written notice of exercise, a short form where you specify how many shares you are buying and how you are paying.⁷ Check with the former employer’s HR or equity administration team to confirm the process.

You generally have two ways to pay:

Cash exercise. You pay the full strike price out of pocket by check, wire, or ACH. Straightforward, but a large grant can require significant liquid capital.
Cashless exercise, also called a same-day sale. A broker sells enough of the newly acquired shares to cover the strike price and tax withholding, and you keep the rest. This works only at publicly traded companies where the shares can be sold immediately.

Once the paperwork and payment clear, the plan administrator updates the company’s records and issues a confirmation — a digital receipt through the platform or a book-entry statement in your name.

If Your Shares Are in a Private Company

Exercising at a private company carries risks a public-company employee does not face.

409A Valuation Drives Your Tax Bill

Private companies set fair market value through periodic independent appraisals called 409A valuations. Your strike price came from one of these at the time of your grant. If the most recent 409A has climbed since then, the spread is wider and the tax at exercise is larger. If the IRS later rejects a company valuation as too low, you can face retroactive tax liability plus a 20% penalty and interest on the understatement under Section 409A.⁸

You May Not Be Able To Sell

Owning private shares is not the same as being able to sell them. Most shareholder agreements include a right of first refusal, which requires you to offer the shares back to the company or its existing shareholders before selling to anyone else. Some agreements block outside transfers entirely until an IPO or acquisition. You could pay a substantial sum to exercise, then hold illiquid shares for years with no guaranteed payout.

Secondary marketplaces sometimes let holders sell private shares to institutional buyers, but they usually work only with well-known late-stage startups, charge broker commissions of 3% to 5%, and often require company approval for any transfer.

Section 83(i) May Let You Defer the Tax

Some private-company employees can defer the income tax from exercise for up to five years under Section 83(i). The company has to grant options or restricted stock units to at least 80% of its U.S. employees with the same rights and privileges, and its stock cannot have been publicly traded in any prior year.⁹ You are not eligible if you are a 1% owner, a current or former CEO or CFO, or one of the four highest-compensated officers. The election has to be made within 30 days of the date your rights in the stock become transferable or are no longer subject to forfeiture.

If You Are Fired for Cause, Everything Can Disappear

A termination for cause — typically serious misconduct such as fraud, theft, or a significant breach of duty — triggers full forfeiture under most plans, including options that already vested. A representative SEC-filed agreement states: “If the Participant’s employment terminates for Cause, all Options, whether vested or unvested, shall be immediately forfeited and canceled.”¹ There is no grace period.

Many plans also carry non-compete and non-solicit clawback clauses that reach past your departure. The same SEC-filed agreement provides that “if, during the Covered Period, the Participant engages in Wrongful Conduct, then any unexercised Options, whether vested or unvested, shall automatically terminate.”¹⁰ Going to work for a direct competitor during a restricted period can retroactively cancel options you have not yet exercised.

If You Are Laid Off, What To Negotiate

An involuntary departure — a layoff, a restructuring, a termination without cause — often gives you room to ask for better equity terms in your severance package. Two provisions are worth pushing on.

Accelerated Vesting

Accelerated vesting turns unvested options into vested ones at termination instead of letting them lapse. Full acceleration, where everything vests at once, is unusual outside executive contracts, but partial acceleration shows up regularly in negotiated severance. One SEC-filed executive severance agreement provides that all equity that would have vested in the 183-day period following termination becomes immediately exercisable.¹¹ A few extra months of vesting can be worth a lot on a growing grant.

A Longer Exercise Window

If the company will not move the vesting line, ask them to move the exercise deadline. A 90-day window may not be enough time to raise the cash, review the company’s outlook, or plan for the tax hit. Six months or a year makes a real difference. One caveat: extending an ISO window past three months converts those options to NSO tax treatment, so weigh the higher tax cost against the extra time.

Double-Trigger Acceleration in an Acquisition

If the company is being acquired, look at your plan for a double-trigger acceleration clause. Under a double trigger, unvested options accelerate only when two things happen: a change of control (a merger or acquisition) and your termination without cause or resignation for good reason within a set period, commonly 9 to 18 months after the deal closes. Single-trigger acceleration, in which the acquisition alone vests everything, is less common and usually reserved for senior executives or founders. During any acquisition, read the plan documents closely; the acquirer may substitute its own equity or cash out your options at the deal price.

1
Securities and Exchange Commission. Employee Stock Option Agreement – Section: Termination of Options
2
Office of the Law Revision Counsel. 26 USC 422 – Incentive Stock Options
3
Office of the Law Revision Counsel. 26 USC 422 – Incentive Stock Options – Section: Special Rules
4
SEC.gov. Heska Corporation 2003 Equity Incentive Plan Non-Qualified Stock Option Agreement
5
Internal Revenue Service. Topic No. 427, Stock Options
6
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
7
Justia. Root Inc Stock Option Notice of Exercise and Related Agreements
8
Office of the Law Revision Counsel. 26 USC 409A – Inclusion in Gross Income of Deferred Compensation Under Nonqualified Deferred Compensation Plans
9
Internal Revenue Service. Guidance on the Application of Section 83(i)
10
Securities and Exchange Commission. Employee Stock Option Agreement – Section: Forfeiture for Competition
11
SEC.gov. Executive Severance and Vesting Acceleration Agreement