The 90-Day Stock Option Exercise Window, Explained

Most stock option grants give you only 90 days after you leave a company to exercise the options you've already vested, or they expire worthless. This is called the post-termination exercise period (PTEP), and it's set by your company's stock plan document, not by a single universal law. If you're weighing a job offer, a resignation, or a layoff, the length of this window can decide whether years of vested equity turns into cash or into nothing.

What Is the 90-Day Exercise Window?

The 90-day exercise window, more formally the post-termination exercise period, is the deadline your stock option plan sets for exercising options you've already vested after your employment ends. Once that window closes, any unexercised vested options are forfeited back to the company, regardless of how long you held them or how much they might be worth.

Where the 90-Day Default Comes From

Ninety days is a market norm, not a fixed legal requirement for every option. It became standard mostly because it matches the tax rule for incentive stock options (ISOs): to keep ISO tax treatment, options generally must be exercised within three months of termination, per Carta's explanation of ISO taxation. Most companies apply that same 90-day window to all grants for consistency, even though non-qualified stock options (NSOs) aren't bound by that IRS deadline. Your specific window is whatever your plan document says, so read it rather than assuming 90 days applies.

ISOs vs. NSOs: Why the Window Matters Differently

For an ISO, missing the 90-day mark usually converts the option to an NSO for tax purposes, permanently losing the favorable ISO treatment even if the company lets you exercise later. NSOs carry no such IRS deadline, so a company can offer NSO holders a longer window without that tax consequence. Know which type of option you hold before assuming "90 days" is a hard rule either way.

Why Do You Only Get 90 Days After Leaving?

You typically get 90 days after leaving because that period is tied to preserving ISO tax status under the Internal Revenue Code, and most plans extend the same deadline to all options for simplicity, per Carta's post-termination exercise period guide. It's a plan design choice built around a tax rule, not a law that caps every option at exactly 90 days.

The Tax Rule Behind It

To retain ISO tax treatment, an option generally must be exercised within three months of termination, longer for death or disability. Exercising after that point doesn't erase the option, but it does erase the favorable tax treatment, taxing the exercise like an NSO instead. This detail is often buried in a plan document rather than spelled out plainly in the offer letter itself.

It's a Plan Term, Not Always a Law

Because the 90-day rule for NSOs is a company choice, not an IRS requirement, some companies have moved away from it. That's a meaningful negotiation point, covered further down.

What Happens If You Miss the Window

If you don't exercise your vested options before the exercise period ends, they expire and you lose them permanently, with no partial credit. It's one of the sharpest all-or-nothing clauses in equity compensation, similar in effect to missing a vesting cliff, except it happens on the way out the door instead of on the way in.

Unexercised Options Expire Worthless

There's no grace period built in by default. If the 90 days (or whatever your plan specifies) passes without you exercising and paying the strike price, the options are gone, even if the company later goes public or gets acquired at a price that would have made them valuable.

The Real Obstacle Is Usually Cash, Not the Deadline

The harder problem for most people isn't remembering the deadline, it's affording it. Exercising means paying the strike price for every share, potentially triggering Alternative Minimum Tax if you're exercising ISOs at a paper gain, exactly when your paycheck from that employer has stopped. See our guide to AMT on ISO exercise for that exposure.

Financing Options If You Can't Pay Out of Pocket

A few financing paths exist for this squeeze: non-recourse exercise loans that cover the strike price and taxes in exchange for a share of eventual proceeds, and company-run tender offers letting employees sell some vested shares for cash to fund exercising the rest. Both carry tradeoffs, including giving up upside or owing fees if the company's value goes to zero, and neither should be arranged in the final week of your window.

Companies That Extended Their Exercise Windows

A small number of well-known companies have moved away from the 90-day default, and their approach is worth knowing about if you're evaluating an offer or negotiating your own terms. Coinbase extended its post-termination exercise period to seven years for employees who stay at least two years, an approach also adopted by Pinterest, while Quora set a ten-year period measured from the grant date, according to reporting on the shift toward longer post-termination exercise periods and Forbes' coverage of VC-backed startups extending PTEPs.

Why This Matters for You

These extensions typically apply to NSOs, since stretching an ISO's window past 90 days converts it to an NSO anyway, so the tax tradeoff is already priced in. If a company advertises an extended exercise window as a benefit, confirm which option type it covers and whether a minimum tenure requirement applies.

What to Look For in Your Own Plan

Don't assume your company follows the 90-day norm or an extended-window approach. The number is set in your specific stock option agreement, and it can differ by grant, so check the actual paperwork rather than going by what you've read about other companies.

How to Check Your Exercise Window Before You Sign

Check your exercise window by asking directly for the post-termination exercise period stated in your option grant or stock plan document, since offer letters rarely spell this number out on their own. This is a detail worth confirming before you accept an offer, not after you've already resigned from your last one.

Questions to Ask Before Accepting

Ask how long you'd have to exercise vested options after resignation, termination, and a layoff, since plans sometimes treat these differently, and whether the window applies equally to all employees. If a recruiter can't answer, ask for the plan document itself. Our guide to negotiation emails for job offers covers how to raise a question like this without it reading as distrustful.

What to Do If You're Already Leaving

If you're already resigning or have been let go, find your exercise deadline immediately, since it counts from your termination date, not from when you get around to reading the paperwork. Work out the total cost of exercising, including likely AMT exposure, before deciding whether to exercise, let the options lapse, or look into financing. If your separation paperwork is dense and you want the relevant clauses pulled out clearly, that's the kind of document Offer XRay is built to scan.

Frequently Asked Questions

Is 90 days always the exercise window after leaving a job?

No. Ninety days is the common default because it matches the ISO tax deadline, but it's a plan term, not a universal law, and some companies set longer windows. Confirm the number in your own stock option agreement.

What happens to unvested options when I leave?

Unvested options are typically forfeited immediately on termination; the exercise window only applies to options you'd already vested. See our guide on vesting cliffs for how vesting itself works.

Do ISOs and NSOs have the same exercise window?

Not necessarily. ISOs are tied to a roughly three-month IRS deadline to keep favorable tax treatment; miss it, and the option is generally treated as an NSO going forward. NSOs have no equivalent IRS deadline, so a company can offer NSO holders a longer window without the same tax consequence.

Can I negotiate a longer exercise window?

It's uncommon to negotiate a custom exercise window as an individual hire, since it's usually set at the plan level. It's more realistic to ask whether the company already offers an extended window as policy and factor that into how you compare offers.

What if I can't afford to exercise before the deadline?

Options include a company tender offer if one is available, or a third-party non-recourse loan against the shares, both of which involve giving up some future value or paying fees. Get the total cost, including likely tax exposure, in writing before deciding, since this is a financial and tax decision worth treating carefully rather than rushing in the final days.

Key Takeaways

• The 90-day post-termination exercise window is a common default, not a universal law; the actual number lives in your stock option agreement.
• Missing the window means forfeiting vested but unexercised options entirely, with no partial credit.
• ISOs carry a roughly three-month IRS deadline to keep favorable tax treatment; NSOs don't, which is why some companies offer NSO holders longer windows.
• A few companies, including Coinbase, Pinterest, and Quora, have extended their windows to several years, usually tied to a minimum tenure requirement.
• Exercising costs real cash upfront, plus possible AMT exposure, so plan for the total cost well before your deadline rather than at the end of it.

The exercise window is easy to overlook while you're focused on salary or the headline equity number, but it's the clause that decides whether vested equity actually becomes money. If you're evaluating a new offer or trying to make sense of the equity section in your paperwork, Offer XRay flags vesting and exercise terms automatically, and pricing starts at $4.99 for two analysis credits.