Post-Termination Exercise Period (PTEP)

The post-termination exercise period (PTEP) is the window of time after you leave a company — for any reason — during which you can still exercise your vested stock options. When the PTEP expires, any unexercised vested options are forfeited permanently and return to the company's option pool. They cannot be recovered, extended, or appealed after the fact.

According to Sequoia's 2026 compensation survey and Carta data on option plan terms, approximately 82% of companies still use a 90-day PTEP — the bare minimum allowed under IRS rules for ISOs to retain their favorable tax treatment. This 90-day window is one of the most financially consequential — and most frequently misunderstood — terms in any startup option grant. Every year, startup employees forfeit millions of dollars of vested options simply because they did not exercise within 90 days of their last day at work.

Why 90 Days: The ISO Tax Rule

The 90-day standard exists because of a specific IRS requirement for Incentive Stock Options under IRC Section 422. ISOs receive favorable federal tax treatment — no ordinary income at exercise, only capital gains at sale — but only if exercised within 3 calendar months (approximately 90 days) of the employee's termination date.

If you exercise ISOs more than 90 days after your last day of employment, those options are automatically reclassified as Non-Qualified Stock Options (NSOs) for tax purposes — regardless of what your grant agreement says and regardless of whether the PTEP is technically still open. You lose the ISO tax advantage retroactively.

This IRS rule is why 90 days became the default: if a company gives employees longer than 90 days to exercise, any ISO grants exercised in the extended window become NSOs. The favorable tax treatment is gone, and the ordinary income on the spread at exercise is owed immediately. Many companies find this trade-off unappealing and simply set the PTEP to 90 days to avoid the ISO conversion complexity.

What Happens to ISOs vs. NSOs at Termination

ISOs after 90 days:

• Days 1–90 post-termination: ISOs can be exercised and retain ISO tax treatment
• Day 91+: any remaining ISOs automatically convert to NSOs
• If the company's PTEP is 90 days, the options simply expire on day 91
• If the company has extended the PTEP to 2, 5, or 10 years: options remain exercisable but are now NSOs — the spread at exercise will be ordinary income, not an AMT preference item

NSOs: No equivalent ISO rule applies. NSOs can be exercised within whatever PTEP the company sets — 90 days, 2 years, 10 years — and the tax treatment does not change based on when within the PTEP you exercise.

See Incentive Stock Options (ISO) in Private Companies and Non-Qualified Stock Options (NSO) in Private Companies for the underlying tax mechanics.

The Financial Trap: Why Most Employees Can't Exercise Within 90 Days

The 90-day window creates a genuine financial crisis for many departing startup employees. Consider what is required to exercise vested options within 90 days:

1. Cash for the exercise price. You must pay the strike price per share × number of vested options. For 50,000 vested ISOs at a $2.00 strike, that is $100,000 in cash — due within 90 days of your last day.

2. Cash for the tax bill. Even for ISOs, exercising and holding creates AMT exposure on the spread. For NSOs or disqualified ISO exercises, ordinary income tax is owed in the year of exercise. If the spread is $8.00 per share and you are exercising 50,000 shares, the spread is $400,000 of ordinary income. At combined federal and California rates of ~50%, that is $200,000 in taxes — due when you file your return for that year.

3. No ability to sell. Private company shares cannot be sold to fund either the exercise price or the tax bill. Every dollar comes from personal savings or external financing.

4. Uncertainty about the company's trajectory. You are being asked to write a large check for shares in a company you just left, without certainty of when (or if) a liquidity event will occur.

The result: the majority of departing startup employees do not exercise their vested options within the PTEP, forfeiting equity they genuinely earned. This is not a rare edge case. It is an extremely common outcome.

Companies That Offer Extended PTEPs

A growing minority of companies — particularly those that are employee-friendly and sophisticated about equity — voluntarily extend PTEPs beyond 90 days. According to Sequoia's 2026 data, approximately 10% of companies now offer PTEPs longer than 90 days.

Notable examples of longer PTEPs in the market:

• Pinterest: 7-year PTEP for long-tenured employees
• Loom: 10-year PTEP for employees with at least 2 years of tenure
• Various other growth-stage tech companies offer 2–5 year PTEPs, often tiered by tenure

Some companies use a tiered approach:

• Under 2 years of tenure: 90-day PTEP
• 2–5 years: 1–2 year PTEP
• 5+ years: 5–10 year PTEP

The extended PTEP is almost always in NSO format (or ISO format for the first 90 days, converting to NSO thereafter). Employees who use an extended PTEP to exercise after 90 days will owe ordinary income tax on the spread at exercise — a real cost, but one that can be planned for over a longer time horizon.

How to Negotiate a Longer PTEP

PTEP is a negotiable term — but most employees never think to ask for it at offer acceptance. The best time to negotiate is at the time of the offer, before you have signed anything.

What to ask:

• "What is the post-termination exercise period for vested options?"
• "Is the PTEP the same for ISOs and NSOs, or different?"
• "Does the PTEP length vary based on tenure at the company?"
• "If I am terminated without cause, does the PTEP extend?"

What to propose if the answer is 90 days:

• Request a 2–5 year PTEP for all options, or at minimum for vested ISOs at the point they would convert to NSOs (i.e., an extended NSO window after day 90)
• Propose a tenure-linked PTEP: 90 days if you leave in the first year, scaling up to 2–5 years for employees with 3+ years

Leverage considerations: Senior engineers, directors, and executives have more leverage to negotiate this term. At seed-stage companies where the option pool is large relative to the company, a longer PTEP is also less dilutive than it would be at a late-stage company. The founders at early-stage companies are often open to this conversation; at larger companies with more formalized equity plans, it may be harder to deviate from the standard.

Even if the company will not change the standard plan terms, ask whether the board would grant an individual modification at the time of your hire. Some companies do make individual exceptions for senior hires without revising the plan for everyone.

The Cost of Not Asking

The PTEP is one of the most important terms in your grant agreement — arguably more important than the number of shares, the strike price, or the vesting schedule, because it determines whether you can realistically exercise at all when you leave.

A grant of 100,000 ISOs at a $1.00 strike at a company now worth $20 per share (409A FMV) looks excellent on paper. But if you leave the company without the cash to exercise (and cover potential taxes) within 90 days, those options are worthless to you regardless of what they are worth on the cap table.

For a full checklist of terms to review and negotiate in any private company equity offer, see Negotiating Equity Compensation at a Private Company.

What to Do If You Are About to Leave and Have a 90-Day PTEP

If you are planning to leave — or have been laid off — and have a 90-day PTEP:

Step 1: Count the days immediately. Your PTEP clock starts on your last day of employment, not the date you receive your separation notice. Count carefully, including weekends.

Step 2: Get the current 409A FMV. Ask HR or check your equity management platform (Carta, Pulley, etc.) for the most recent 409A valuation. This determines the spread and the potential tax liability.

Step 3: Calculate your total exercise cost. Strike price × number of vested options = cash needed. Estimate the tax impact (AMT for ISOs, ordinary income for NSOs) based on your current income and tax bracket.

Step 4: Consult a tax advisor before exercising. The tax math at departure is complex and time-sensitive. A qualified tax advisor can help you model the cost, decide how many options to exercise, and plan for the tax filing.

Step 5: Decide and act before the deadline. Do not let the deadline pass by default. A deliberate decision not to exercise is better than accidentally losing vested equity because you ran out of time.

California Note

California taxes the spread at NSO exercise (including disqualified ISOs exercised after day 90) as ordinary income at rates up to 13.3%. For California residents exercising during a PTEP, the combined federal and California tax on the spread can reach 50%+.

California also has no time limitation that mirrors the ISO 90-day rule — the conversion from ISO to NSO treatment is a federal rule only. At the state level, all option exercises on spread are taxed as ordinary income regardless of whether the options were ISOs or NSOs. The California tax impact of exercising during a PTEP is therefore consistent whether you exercise on day 45 or day 400 (assuming the company offers an extended PTEP).

This article is for educational purposes only and does not constitute tax, legal, or financial advice. PTEP terms vary by company and grant type. Always review your specific option agreement and consult a qualified tax advisor before the deadline.