Leaving a job is more than a career transition — it can trigger a cascade of deadlines and decisions around your equity compensation. If you’re wondering what happens to stock options when you leave, the answer starts with understanding your post-termination exercise period (PTEP), your unvested equity, and the tax consequences of each choice you face.
From incentive stock options (ISOs) that typically expire in 90 days to unvested restricted stock units (RSUs) that disappear the day you depart, the choices you make in those final weeks can shape your financial picture for years to come.
That statistic underscores how many professionals leave meaningful value on the table, not because they want to, but because the rules and timelines catch them off guard.
Here’s a framework for understanding those decisions and how you might approach them.
Your stock option exercise window: The 90-day clock
If you hold incentive stock options, the most critical deadline is likely the post-termination exercise period. For most plans, that window is 90 days from your last day of employment. Miss it, and your vested options typically expire worthless.
The 90-day standard exists because of a specific tax rule. Under Section 422(b) of the Internal Revenue Code, an employee may need to exercise ISOs within three months of leaving employment for the ISOs to retain their preferential tax treatment. Exercise after that window, and your ISOs automatically convert to nonqualified stock options (NSOs), losing their favorable capital gains treatment and triggering ordinary income tax on the spread at exercise.
Some companies have voluntarily extended their exercise window to one year, five years, or even 10 years. Although your employer might offer a longer window, the IRS still strips ISO tax treatment after 90 days. Any exercise beyond that point is taxed as an NSO, regardless of what your plan allows. Understanding what happens to stock options when you leave starts with knowing this deadline.
Unvested equity when leaving a job: What you lose
Restricted stock units operate differently from stock options. You don’t exercise them — they vest on a vesting schedule set by your employer, and the company delivers shares (or their cash equivalent) when they do. The consequence when you leave is that any RSUs that haven’t vested by your departure date are forfeited.
Unlike options, there’s no post-termination exercise period to earn unvested RSUs. As soon as you leave, those units are gone. Limited exceptions exist — some plans include acceleration provisions tied to a change-in-control event, and severance agreements can sometimes include negotiated equity treatment. But the default rule is forfeiture.
For professionals at private companies, double-trigger acceleration provisions add another layer. These RSUs vest on a time schedule but don’t settle until a liquidity event, such as an IPO or acquisition. If you leave before that event, your plan documents determine whether your time-vested, unsettled units survive your departure. Review those documents before assuming anything.
When considering what happens to stock options when you leave, don’t assume RSUs follow the same rules — they don’t.
The exercise decision: Cash, sell, or swap
If you decide to exercise your vested options within the 90-day window, you face a financial decision that can require significant capital. You need cash to pay the exercise price, and you may also face alternative minimum tax (AMT) liability on the bargain element, which is the difference between the fair market value and your strike price. Your strike price is the fixed price per share that your employer set when you were granted the stock options, and it’s the price you pay to buy the shares if you choose to exercise.
The AMT consideration is where many professionals get caught up. If you exercise an ISO and hold the shares through year-end, the IRS counts that same bargain element as income under the AMT — even though you haven’t sold a single share. Depending on your income and the size of the spread, this can trigger a tax bill that rivals the cost of the exercise itself.
The following three approaches are worth considering.
1. Cash exercise
Pay the strike price out of pocket and hold the shares. This preserves ISO tax treatment but requires up-front capital and creates AMT exposure that you should model before committing.
2. Same-day sale
Exercise and immediately sell some or all shares to cover costs. This cashless exercise approach reduces AMT risk but converts the transaction to a disqualifying disposition, meaning ordinary income tax applies to the spread.
3. Stock swap
Use shares you already own from prior exercises or employee stock purchase plan purchases to cover the exercise cost. This approach can preserve cash but carries its own tax implications.
Each approach involves trade-offs among cash flow, tax treatment, and portfolio concentration. The right choice depends on your full financial picture.
Coordinated strategies across your financial plan
Your equity decisions may be less effective if they happen in isolation. Here’s how integration may help across other key areas of your financial life.
Tax planning
Before exercising ISOs, model the AMT impact. A large exercise can trigger a significant tax bill before you sell a single share. Consider timing the exercises to manage your tax brackets, and coordinating with other income events. If you’re also navigating the state and local tax (SALT) deduction phaseout at higher income levels, the timing of your exercise matters even more.
Investment management
Exercising and holding can create a concentrated position in a single stock. Develop a portfolio diversification plan that helps reduce concentration risk while managing tax consequences through a structured selling strategy. A single-stock position can be volatile, so consider how it fits within your broader portfolio allocation.
Estate planning
If you exercise and hold shares, review your beneficiary designations and consider whether gifting strategies make sense for your wealth transfer goals. Coordinating equity decisions with your estate plan can help you transfer your wealth efficiently to the next generation.
Insurance
A job change is a natural time to review your life and disability insurance coverage. If your equity compensation represented a significant portion of your financial protection, ensure your coverage reflects your new circumstances.
Act before your last day
One of the biggest mistakes is waiting until you’ve left to understand what happens to stock options. By then, the 90-day clock is already ticking, and the window for thoughtful planning has narrowed. Review your grant documents and understand your deadlines. Your equity compensation is likely to represent years of effort. With the right planning, you can make informed decisions that help protect and grow the wealth you’ve built.
With Mercer Advisors, you can create a plan with a wealth advisor and tax professional before your departure date. We integrate financial planning, investment management, tax planning and preparation, estate planning, and insurance solutions into one comprehensive wealth management solution.
If you want to start planning now.
FAQs
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When you leave a job, your vested stock options enter a post-termination exercise period — typically 90 days. You have that window to exercise your options before they expire. Unvested options are forfeited immediately. The specific rules depend on your grant documents and equity plan, so review them before your last day.
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For incentive stock options, the post-termination exercise period is generally 90 days from your last day of employment. This 90-day deadline is tied to IRS rules: To preserve the preferential tax treatment of an incentive stock option (ISO), you may need to exercise your options within three months of leaving. After that, ISOs convert to nonqualified stock options and could lose their tax advantages.
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The decision depends on several factors, including the exercise cost, potential tax liability, and your financial goals. Exercising before you leave can give you more time to plan, but it requires capital and may trigger AMT. A Mercer Advisors wealth advisor can help you model the scenarios and determine the right approach for your situation.
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You’re not required to exercise them, but if you don’t do so within 90 days, your options typically expire. And if your company offers a longer window, exercising after 90 days converts your incentive stock options (ISOs) to nonqualified stock options (NSOs) for tax purposes, meaning ordinary income tax applies to the spread. Consider the cost, the tax implications, and the potential value before deciding.
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A Mercer Advisors wealth advisor can review your grant documents, model the tax implications of exercising, and help you coordinate decisions across your financial plan. We can match you with an advisor who has experience with stock options, RSUs, and the tax rules that apply when leaving a company.
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Your equity grant documents are typically available through your company’s equity management platform. You can also request copies from your HR department. Review the post-termination exercise period, vesting schedule, and any acceleration provisions before your departure date.
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Incentive stock options (ISOs) may need to be exercised within 90 days of leaving to preserve their preferential tax treatment. After 90 days, they automatically convert to nonqualified stock options (NSOs), which are taxed as ordinary income on the spread at the time of exercise. NSOs don’t have the 90-day ISO requirement but also don’t offer the same capital gains potential. Your tax outcome depends on which type you hold and when you exercise.
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Neither option is universally better. Exercising options before leaving your job can give you more control over timing and may simplify the process, but it requires capital while you’re still employed. Exercising options within 90-days after leaving may preserve incentive stock option (ISO) tax treatment but may add time pressure. The right choice depends on your cash flow, tax situation, and financial goals.
1“Founders Will Get Back 50 Percent of Employee Options.” Carta, Sept. 5, 2025.
All expressions of opinion reflect the judgment of the author as of the date of publication and are subject to change. Some of the research and ratings shown in this presentation come from third parties that are not affiliated with Mercer Advisors. The information is believed to be accurate but is not guaranteed or warranted by Mercer Advisors. Content, research, tools and stock or option symbols are for educational and illustrative purposes only and do not imply a recommendation or solicitation to buy or sell a particular security or to engage in any particular investment strategy. All investing involves risk, including the possible loss of principal.
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