Stock options are not perpetual. They have a hard expiration date written into your grant agreement — and when that date passes, the right to purchase your shares at the strike price is gone permanently. There is no grace period, no exception process, and no way to reinstate an option once it has expired.
This article walks through every way a stock option can expire — the 10-year cliff that applies to most grants, the short post-termination exercise period (PTEP) that kicks in when you leave, the separate 90-day IRS rule that governs incentive stock options (ISOs), and what your real choices are when you find yourself running out of time. If you are still inside the exercise window today, the deadline is closer than most shareholders realize.
This is not tax advice. Consult a qualified tax professional before you exercise stock options. AMT exposure on ISO exercises and ordinary income on NSO exercises can be substantial, and the right move depends on your equity type, your state, and your full tax picture.
Key concept
A vested option is a right to buy, not a share. Until you exercise — paying the strike price to convert the option into actual stock — the option is a time-limited contract. When the contract expires, the right disappears. Vested does not mean permanent; it means earned-but-not-yet-converted.
The Two Clocks That End in Expiration
Almost every stock option grant has two independent expiration deadlines running at the same time. The option ends on whichever one arrives first.
Clock 1: The 10-year contractual life. The grant agreement specifies a maximum option life — almost always 10 years from the grant date. This is a hard ceiling. The IRS requires it for ISOs, and most NSO plans adopt the same convention for consistency. The clock runs whether you are still employed or not.
Clock 2: The post-termination exercise period (PTEP). When you stop working for the company, the post-termination exercise period starts immediately. The standard PTEP is 90 days. Some companies set 30 or 60 day windows. Others offer extended windows of 5 or 10 years. Whatever your plan specifies, that countdown begins on your last day of employment.
For an employee who joins early and stays through the entire vesting period, Clock 1 (the 10-year cliff) is the relevant deadline. For someone who leaves a long-private company, Clock 2 (the short PTEP) usually arrives first — often by years.
How the 10-Year Option Cliff Works
The 10-year option cliff is a single date written into your grant: typically the tenth anniversary of the grant date. If your grant was issued on April 15, 2017, the options expire on April 14, 2027 — regardless of how many vested shares you hold, regardless of whether the company has gone public, and regardless of whether you are still an active employee.
For employees of companies that stay private for a long time, this is becoming a more common bind. The original 10-year horizon was set when companies typically went public in 5 to 7 years. With many venture-backed companies now staying private for 10 to 15 years, employees can hit the contractual cliff while still working at the company — and still holding options on shares that have no liquidity path.
Example
You joined a startup in 2017 with 40,000 NSOs at a $1.00 strike. The company is still private in 2027, with a 409A-implied common FMV of $18. Your full position has vested — $720,000 of paper value. But your grant expires on the 10-year anniversary. If you do not exercise before that date, the entire position is forfeited. The exercise cost is $40,000; ordinary income tax on the $680,000 spread is the second, larger number you have to plan for.
Some companies do amend stock plans to extend the 10-year life — converting affected options into a longer-life replacement grant, or repricing into a new option pool — but these are negotiated, plan-specific changes, not a right you can claim. If your 10-year cliff is approaching while you are still employed, raise it with HR and the equity plan administrator early. Plan amendments take board action and time.
How the Post-Termination Exercise Period (PTEP) Works
The PTEP is the much shorter window that applies after you leave the company. The default in most early-stage equity plans is 90 days. Several other patterns are common.
30-day window. Rare but not unheard of, particularly in older plans or at companies where the equity committee never revisited the default. Thirty days is barely enough time to gather grant documents, calculate the full exercise cost, and arrange financing — let alone make a considered decision.
60-day window. Common at companies that wrote their plans with the IRS 90-day ISO rule in mind but still kept the window short for administrative simplicity. A 60-day exercise window forces a faster decision than the 90-day standard, particularly for ISO-holders worried about the parallel ISO conversion deadline.
90-day window (the standard). The most common default in early-stage VC-backed companies. Ninety days aligns with the IRS requirement for ISOs to keep their favorable tax treatment, so the company can use a single window for both option types.
Extended windows: 1, 5, or 10 years. A growing number of companies — typically those that have thought carefully about employee equity fairness — set extended PTEPs of one year, five years, or even the full ten-year contractual life. With an extended window, you do not have to make a rushed, high-stakes financial decision the moment you leave. You can wait until a liquidity event (an IPO, a tender offer, or an acquisition) before deciding whether to exercise.
⚠️ Your PTEP is specified in your individual option grant agreement and the company's equity incentive plan — not what HR said verbally, not what a colleague has, not the default you assumed. Pull both documents before you make any plans around an exit.
The clock starts on your last day of employment. The plan administrator will not send a reminder when the window is closing. For a detailed walkthrough of the PTEP and the related decisions, see what happens to your stock options when you leave a startup.
The 90-Day ISO Rule — Separate From Your PTEP
There is one more deadline that confuses almost everyone: the IRS 90-day rule for incentive stock options. This is not the same as your company's PTEP. It is a separate IRS rule with a separate consequence.
To preserve ISO tax treatment after leaving a company, you must exercise the ISO within 90 days of your last day. After 90 days, the option does not necessarily expire — that depends on your PTEP — but the IRS automatically reclassifies it as a non-qualified stock option (NSO). If you exercise an ISO on day 91, the tax consequences are NSO consequences: ordinary income on the spread at exercise, instead of ISO/AMT treatment.
This rule lives independently of the PTEP. If your company offers a 5-year extended exercise window for ISOs, you can still exercise on month 18 — but the option you exercise will no longer be an ISO for tax purposes. It will be an NSO.
Key concept
Two parallel 90-day clocks can apply at once: your company's PTEP (the option-still-exists deadline) and the IRS ISO conversion deadline (the option-keeps-its-tax-status deadline). For a shareholder with ISOs at a company that uses the standard 90-day PTEP, both clocks happen to expire on the same day. For a shareholder with ISOs at a company that offers an extended PTEP, the IRS clock expires first — and the option survives, but its tax treatment changes. Read your grant agreement, then read the equity plan, then check the option type on each tranche.
For the full mechanics of ISO and NSO tax treatment at exercise, see stock options vs. RSUs vs. actual shares.
What "Running Out of Time" Actually Looks Like
The phrase running out of time to exercise options covers several different fact patterns. The right move depends on which one you are in.
Pattern A: You just left, with vested options and a 90-day PTEP. This is the classic case. The clock started on your last day. You have roughly three months to gather documents, calculate the full exercise cost (strike plus tax), arrange cash or financing, and submit the exercise. Day 60 is the realistic "decision deadline" if your company expects a few weeks for paperwork to clear.
Pattern B: You are still employed, but the 10-year cliff is approaching. The company is still private. Your earliest grants are within 12 to 24 months of their contractual expiration. The decision is whether to exercise into illiquid shares (with full out-of-pocket cost and tax) or let the options expire. Some companies will entertain plan amendments here; the conversation needs to happen well before the cliff.
Pattern C: You left a long time ago and forgot you had vested options. Unfortunately, the PTEP has almost certainly closed. Vested options that were not exercised inside the window are gone. Pull your old grant documents anyway — there is a remote chance you had an extended-window grant that is still alive — but assume the worst until the paperwork says otherwise.
Pattern D: You have ISOs, the 90-day IRS deadline has passed, but your PTEP is longer. The options are still alive, but they have lost ISO status. Exercising now will be taxed as an NSO exercise — ordinary income on the spread. Plan accordingly.
What Happens If You Let Your Options Expire
If the deadline passes without an exercise, the options are forfeited. Specifically:
The right to purchase disappears. The option contract terminates. The strike price you negotiated, the spread you watched grow, the years of vesting — none of it carries forward.
The shares return to the option pool. The reserved shares behind your option go back into the company's pool and become available for future grants to current employees. From the company's perspective, nothing is lost; it has a re-issuable pool of equity.
You receive nothing. No cash payout, no replacement equity, no "good faith" gesture. The forfeiture is automatic and complete.
The deadline cannot be reopened. Even if you missed the window by a day, the option is gone. Boards do not typically grant exceptions for individual shareholders — it would set a precedent the company cannot manage across thousands of employees, and it can also create securities-law complications.
⚠️ Forfeited stock options do not generate a tax loss. Because you never owned the underlying shares, there is no realized loss to deduct. The economic loss is real; the tax benefit of a deductible capital loss does not apply.
The most common pattern of failure is not a deliberate decision to let options expire. It is inaction. The shareholder pulls grant documents, looks at the exercise cost plus the tax bill, decides "I will figure this out later," and then later never comes. The window closes.
Your Choices Before the Window Closes
When you have vested options inside a closing window, three practical paths exist. Each has different cash, tax, and upside consequences.
1. Exercise the options yourself. Write a check (or wire) for the strike price multiplied by the number of options you are exercising. For NSOs, set aside cash for the ordinary income tax on the spread. For ISOs (exercised inside the 90-day IRS window), set aside cash for the AMT estimate. After exercise, you own real shares — illiquid, but yours.
2. Use third-party exercise financing. Firms such as 137 Ventures, Liquid Stock, ESO Fund, Quid, and Section Partners advance the strike price (and sometimes the AMT) in exchange for a share of the eventual exit proceeds. The structure is typically non-recourse: if the company fails, you owe the lender nothing beyond the shares. The cost is a meaningful slice of the eventual gain. Useful when you have conviction in the company but cannot fund the exercise yourself.
3. Let the options lapse. Sometimes the right answer. If the strike price is higher than your independent estimate of secondary value (the options are underwater), exercising would be a guaranteed loss. If the cash and tax cost dwarf the realistic upside, walking away can be the rational choice. The decision should be based on a clear-eyed look at the math — not on inertia.
For a full walkthrough of the exercise mechanics — cash vs. cashless, AMT calculations, the 83(b) election for early exercises, and what shows up on your tax return — see how to exercise stock options at a startup.
For more on this topic
For the underlying question — why you cannot simply sell unexercised options to fund the exercise — see Can You Sell Your Employee Stock Options Before IPO?
The Sequence: What to Do When Your Window Is Closing
If you have a closing exercise window — whether from a termination or an approaching 10-year cliff — the practical sequence is roughly the same.
Step 1: Pull the authoritative documents. Your individual option grant agreement, the company equity incentive plan, and your latest 409A-derived fair market value. Carta, Pulley, Shareworks, or whoever administers the cap table should surface all three. Verbal answers from HR do not replace the documents.
Step 2: Calculate the full out-of-pocket cost. Strike price × vested options = the cash you owe the company. Then layer the tax: ordinary income for NSOs (and ISOs exercised past the 90-day IRS deadline), AMT for ISOs exercised inside the window. The total — not the strike alone — is the number that decides whether you can afford to exercise.
Step 3: Get an independent estimate of share value. The 409A is a regulatory valuation, not a market price. Common shares in a private company are typically worth meaningfully less than the headline last-round valuation, because preferred investors get paid first. See how much are your stock options worth for the four-prices framework that helps separate signal from headline.
Step 4: Decide whether the math works. Compare the total out-of-pocket cost (strike + tax) to your independent value estimate. If the spread is meaningfully positive and you have conviction in the company, exercising before expiration captures real value. If the spread is small or you are underwater, letting the options lapse may be the right call.
Step 5: If exercising, choose your funding path. Cash exercise is cleanest. Third-party financing is useful when you do not have the cash but want to capture upside. If a tender offer or company-organized secondary is open, an "exercise into the tender" can sometimes coordinate the exercise and sale in a single transaction — see tender offers explained.
Step 6: Submit the exercise paperwork early. Companies will not issue shares until your payment clears, and paperwork can take 1–2 weeks to process. Build a buffer; do not submit on day 89 of a 90-day window. If anything goes wrong with the wire or the documentation, you need time to fix it before the deadline.
Step 7: Track AMT credits and cost basis. If you exercised ISOs and paid AMT, that creates a credit you can use against regular tax in later years (Form 8801). Keep the exercise paperwork — you will need cost basis records when you eventually sell the shares. See tax considerations when selling private shares for the full picture.
Common Mistakes Before Expiration
Six recurring stumbles when an exercise window is closing.
Assuming the 90-day window is universal. It is the default, not the law. Some plans use 30 or 60 days; others use 1, 5, or 10 years. Confirm your specific PTEP — do not assume.
Confusing the IRS 90-day ISO rule with the PTEP. These are two different deadlines. An extended PTEP keeps the option alive after 90 days but does not preserve ISO tax treatment.
Waiting until the last week to gather documents. Pulling grant agreements, requesting the equity plan, confirming the FMV, and getting a value estimate takes longer than expected. Start early.
Anchoring on the last-round valuation. The headline preferred-round price is not what common shares are worth. Exercising at a "spread" that disappears under cap-table reality is a real risk. See the last-round valuation myth.
Forgetting the tax bill is due in this calendar year. Exercising a meaningful NSO position in December puts the entire spread on this year's tax return — often at a time when withholding will be miscalculated. Either spread the exercise across two tax years (if the window allows) or pre-pay estimated tax.
Treating "exercise and sell" as a single action. Exercising creates illiquid private shares. Without a coordinated tender offer or active secondary buyer, you cannot simply turn the shares into cash to cover the exercise cost. For the path from exercised shares to actual liquidity, see how to sell shares in a private company.
Key Takeaway
Stock options have hard expiration dates, and missing them costs real value. Two clocks matter: the contractual 10-year life from grant, and the post-termination exercise period after you leave. Whichever ends first ends the option. For most former employees, the PTEP is the binding deadline — and 90 days is the most common, though shorter and longer windows exist. For long-tenured employees at long-private companies, the 10-year cliff is now arriving while shareholders are still on staff.
The expiration is a contract, not a suggestion. Inaction does not pause the clock. If you have vested options inside a closing window, get the documents, run the math on the full out-of-pocket cost, and decide deliberately — exercise, finance, or walk away — before the deadline decides for you.
Before your exercise window closes
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Earlyasset, Inc. does not provide investment advice and is not a registered investment adviser. Pricing estimates are algorithmic and do not constitute an offer to buy or sell securities. All transactions respect the company's right of first refusal (ROFR) and any transfer restrictions in your equity agreements. Direct liquidity is provided by Earlyasset Capital, LLC, a separate entity from Earlyasset, Inc.
Tax disclaimer: This article is general educational content only and does not constitute tax, legal, or financial advice. Tax treatment of stock option exercises varies significantly based on equity type (ISO vs. NSO), holding period, state of residence, individual circumstances, and other factors. Consult a qualified CPA, tax attorney, or financial advisor before making any exercise or transaction decision. Earlyasset, Inc. is not a tax advisor and does not provide tax guidance.