What Is the 90-Day Post-Termination Exercise (PTE) Window?
The post-termination exercise window is the deadline to buy your vested stock options after you leave a company. 90 days is standard, though it varies by company and can run much longer.
The post-termination exercise (PTE) window is the amount of time you have, after your last day of employment, to exercise your vested stock options before they’re forfeited back to the company. Ninety days is the most common length by far, and it’s set by your company’s option plan, not by law. Some companies now offer longer windows, a few years, or even a decade, so the number that actually applies to you is the one printed in your grant agreement, not the industry default.
Why do options expire after you leave?
Options expire on a set schedule because that schedule is a contractual term the company chose when it wrote its equity plan, not a legal requirement. Most option plans historically set the window at 90 days as a matter of convention, largely because that length lines up with the tax treatment of incentive stock options (more on that below). It’s a company policy decision, and different companies make it differently.
How does the ISO/NSO distinction affect this window?
Incentive stock options (ISOs) and non-qualified stock options (NSOs) are the two types of stock options, and they’re taxed differently. ISOs can qualify for favorable long-term capital gains treatment, while NSOs are taxed as ordinary income on the spread at exercise. This distinction matters for the PTE window because of a rule that catches a lot of people off guard: even if your company gives you years to exercise after you leave, your ISOs automatically convert to NSOs 90 days after your last day, regardless of the extended deadline. The IRS sets that 90-day cutoff for ISO tax treatment specifically. So, your company can extend how long you’re allowed to buy the shares, but it can’t extend how long they stay ISOs.
Do all companies use a 90-day window?
No. The 90-day window is still the most common setup as of 2026, but a growing number of companies have voluntarily extended it. Pinterest, for instance, uses a 7-year window, and some companies, including Loom, offer a 10-year window for employees who’ve been there at least a couple of years. These extensions are a company-by-company choice, often adopted to make departures less punishing for long-tenured employees, and they don’t change the ISO-to-NSO conversion timeline described above. Check your own grant agreement and any separation paperwork. Don’t assume either the 90-day standard or a longer window applies without confirming it.
What happens if I don’t exercise within the window?
If you don’t exercise your vested options before the window closes, they’re forfeited. They go back into the company’s option pool, and you have no further claim to them. There’s no partial credit and no compensation for options you don’t buy; whatever you paid in vesting time simply doesn’t convert into shares. This is different from unvested options, which are forfeited automatically the day you leave, regardless of any exercise window. The PTE window only applies to shares you’d already earned the right to buy.
Worked example
Say you vested 15,000 stock options over three years before deciding to leave your company. Your PTE window is the standard 90 days. On day 91, any of those 15,000 options you haven’t exercised are gone, with no way to reclaim them, regardless of how much the company’s valuation might rise afterward. If you’d exercised 6,000 of them by day 90 and let the rest expire, you’d hold 6,000 shares (subject to whatever exercise cost and tax consequences that purchase created) and forfeit your claim to the other 9,000.
What are the options before the window closes?
A few paths, each with different tradeoffs: exercise all your vested options (full cost and full tax exposure, full upside if the company succeeds); exercise a portion you can afford (smaller cost, smaller potential upside, no risk on the rest); let all of them expire (no cost, but you give up any future value entirely); or ask the company whether it will extend your window (some do, especially for longer-tenured employees, but there’s no obligation to grant this). The cost of exercising, and how people typically cover it, is its own decision; we cover that decision in a separate article.
FAQ
How many days is the standard post-termination exercise window? 90 days is the most common length, though it’s set by each company’s option plan and can vary. Check your specific grant agreement.
Can my company extend my exercise window after I’ve already left? Some companies do grant extensions on a case-by-case basis, but there’s no requirement that they do, and it’s not something to assume will happen.
What happens to unvested options when I leave? Unvested options are forfeited immediately upon departure in nearly all standard option agreements. The PTE window only applies to options you’d already vested.
Do I lose ISO tax treatment if I wait past 90 days to exercise? Yes. Regardless of how long your company’s exercise window runs, ISOs convert to NSOs 90 days after your last day if they haven’t been exercised, which changes how the spread is taxed.
Is the 90-day window the same at every startup? No. It’s a company-specific policy. A small but growing number of companies offer significantly longer windows, sometimes several years.
What to do next
The number that matters is the one in your own option grant and separation documents, not the industry standard described here. If you’re within your window and weighing whether and how to exercise, the cost breakdown and financing tradeoffs are covered in a companion piece, I’m Leaving My Startup — How Do I Pay to Exercise My Stock Options?, and you can model your equity at movewealth.io.
MoveWealth is not a broker-dealer, investment adviser, or lender. This is educational content, not financial, tax, or legal advice. Consult a qualified professional about your specific situation.