When your company goes public, your employee stock options don’t vanish and they don’t automatically pay out. They keep vesting on the same schedule you already have, but the shares they let you buy are now traded on a public market at a real, visible price. That changes what exercising is worth, what taxes you owe, and when you can actually sell. Here is what happens to stock options in an IPO, and the decisions that follow.
Two things usually surprise people. First, you almost certainly can’t sell on day one: underwriters require a lock-up, typically 180 days. Second, the tax bill depends heavily on whether your grant is an incentive stock option (ISO) or a non-qualified stock option (NSO), and on how you time the exercise and sale.
Vesting Keeps Running on Its Original Schedule
Going public does not, by itself, change your vesting timeline. If you had two years left to vest the day before the IPO, you have two years left the day after. What can change the timeline is an acceleration clause written into your grant agreement, and not every company includes one.
Acceleration comes in two forms. Single-trigger acceleration activates on the IPO alone, causing some or all unvested options to vest immediately. Double-trigger acceleration requires both the IPO and a qualifying event afterward, usually involuntary termination within a set period (often 12 months). Double-trigger is far more common because companies don’t want their entire workforce fully vested and heading for the exits on listing day.
If your agreement has single-trigger language, read it before the IPO closes. A wave of options vesting at once can quietly blow through the ISO annual limit described below and convert part of your grant to NSO treatment, with no way to undo it after the fact.
The Lock-Up Period Blocks Selling
Even after the IPO prices and shares start trading, you almost certainly cannot sell yours right away. IPO underwriters require company insiders and employees to sign a lock-up agreement preventing sales for a set period. The most common lock-up is 180 days.1Investor.gov. Initial Public Offerings – Lockup Agreements The point is to prevent a flood of selling that would tank the price right after the company begins trading.
Some lock-ups include early release provisions. These might let non-executive employees sell a small percentage of shares on the first trading day, or release a portion of locked-up shares if the stock trades a certain amount above the IPO price (commonly 20% to 50%) for a sustained number of trading days. Others use staggered releases tied to earnings announcements. The 180-day standard is common, not universal, so read your specific terms.
Even after the lock-up expires, expect internal blackout periods around quarterly earnings that block trading for all employees regardless of role.
How to Actually Exercise Once You Can
To exercise, you need to cover the strike price and any required tax withholding. Post-IPO, three methods are usually available through your company’s stock plan administrator or designated brokerage.
- Cash exercise. You pay the full strike price and taxes out of pocket and keep every share. This makes sense if you have the cash and want to hold for future appreciation or to start a long-term capital gains clock.
- Sell-to-cover. The broker sells just enough shares to cover the strike price and tax withholding, then deposits the rest into your account. No upfront cash required, but you end up with fewer shares than you exercised.
- Cashless exercise, also called a same-day sale. The broker sells all the shares at once and pays you the net proceeds after strike price and taxes. Simplest, no capital needed, no shares left.
For NSOs, the broker handles income tax and payroll withholding at exercise. For ISOs, there is generally no withholding at exercise, but your employer files Form 3921 reporting the details you’ll need at tax time and for any AMT calculation.2Internal Revenue Service. Instructions for Forms 3921 and 3922 Whichever method you pick, the shares stay subject to any lock-up.
NSO Tax Treatment: Ordinary Income at Exercise
Exercising an NSO is a straightforward taxable event. The spread between the stock’s fair market value on the exercise date and your strike price is taxed as ordinary income. Your employer treats the spread as compensation and withholds federal income tax, Social Security tax (6.2% up to the annual wage base), and Medicare tax (1.45%, plus an additional 0.9% if your wages exceed $200,000).
Your tax basis in the shares equals the strike price plus the ordinary income recognized at exercise. When you later sell, any difference between the sale price and that basis is a capital gain or loss. Hold more than a year after exercise and the gain qualifies for long-term capital gains rates. Sell sooner and it’s short-term, taxed at ordinary rates. NSO holders effectively pay ordinary income tax once at exercise and capital gains tax on anything the stock gains afterward.
ISO Tax Treatment and the AMT Trap
ISOs don’t trigger ordinary income tax or payroll taxes at exercise. That is the headline benefit. Your basis for regular tax purposes is just the strike price, and nothing is withheld.
The catch is the Alternative Minimum Tax. The AMT is a parallel calculation that adds certain items back into your income so higher earners can’t reduce their tax too far. The ISO spread at exercise is one of those add-back items.3Office of the Law Revision Counsel. 26 USC 56 – Adjustments in Computing Alternative Minimum Taxable Income You calculate your tax under both systems and pay whichever is higher.
For 2026, the AMT exemption is $90,100 for single filers and $140,200 for married couples filing jointly, phasing out starting at $500,000 and $1,000,000 respectively.4Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 A large ISO exercise at IPO-level prices can easily push the spread into six figures, blow past the exemption, and generate a real AMT bill. AMT paid on ISO exercises does produce an AMT credit that can offset regular tax in later years when you don’t owe AMT.
The $100,000 ISO Annual Limit
There is a cap on how many ISOs you can exercise for the first time in any calendar year. If the total fair market value of shares becoming newly exercisable exceeds $100,000, every option above that threshold is automatically treated as an NSO.5Office of the Law Revision Counsel. 26 USC 422 – Incentive Stock Options Value is measured as of the grant date, and options apply in the order granted. If IPO-related acceleration causes multiple years of options to vest at once, you can bust the cap in a single year and lose ISO treatment on the excess.
Holding Periods: Qualifying vs. Disqualifying Dispositions
To get the full ISO tax benefit, you must meet two holding periods before selling: at least two years from the grant date and at least one year from the exercise date.5Office of the Law Revision Counsel. 26 USC 422 – Incentive Stock Options A sale meeting both is a qualifying disposition, and the entire gain is taxed at long-term capital gains rates.
For 2026, long-term capital gains rates are 0% on taxable income up to $49,450 for single filers ($98,900 married filing jointly), 15% up to $545,500 ($613,700 joint), and 20% above those thresholds.6Tax Foundation. 2026 Tax Brackets and Federal Income Tax Rates Compared to ordinary income rates reaching 37%, the difference on a big gain is significant.
Sell before meeting both holding periods and you have a disqualifying disposition. The spread at exercise (or the actual gain on the sale, if smaller) is retroactively taxed as ordinary income. Anything beyond that is a capital gain. The trade-off is that a disqualifying disposition eliminates the AMT adjustment for that exercise, which occasionally makes it the better financial choice. Run the numbers both ways before selling.
Estimated Taxes and the Net Investment Income Tax
Capital gains from selling your shares can also trigger the Net Investment Income Tax, a separate 3.8% tax on the lesser of your net investment income or the amount by which your modified adjusted gross income exceeds $200,000 for single filers ($250,000 married filing jointly).7Office of the Law Revision Counsel. 26 USC 1411 – Imposition of Tax Those thresholds don’t adjust for inflation, so more people cross them each year, and a single large post-IPO sale easily can.
A large exercise also creates an estimated tax problem. The IRS expects taxes throughout the year, not at filing. If withholding doesn’t cover the liability and you’ll owe $1,000 or more, you face an underpayment penalty unless you make quarterly estimated payments. This is easy to miss with ISOs, where nothing is withheld at exercise but the AMT hit can be large. One practical workaround: increase income tax withholding on your regular paycheck by filing an updated W-4.8Internal Revenue Service. Estimated Taxes
If You Used a Section 83(i) Deferral
Some employees at qualifying private companies elect to defer tax on exercised options for up to five years under Section 83(i). If you did, the IPO ends the deferral. One of the statutory triggering events is the first date the company’s stock becomes readily tradable on an established securities market.9Office of the Law Revision Counsel. 26 USC 83 – Property Transferred in Connection With Performance of Services The deferred income becomes taxable in the year the company goes public, even if the lock-up prevents you from selling shares to raise the cash. Plan for that squeeze well before the IPO date is set.
What If Your Options Are Underwater
Not every IPO makes employees rich. If the post-listing share price sits below your strike price, your options are underwater and have no intrinsic value. Exercising would mean paying more per share than you could sell for on the open market.
You don’t have to do anything. Underwater options cost nothing to hold, and stock prices can recover. Your options remain valid until they expire, which for ISOs is a maximum of 10 years from the grant date.5Office of the Law Revision Counsel. 26 USC 422 – Incentive Stock Options If the price climbs back above your strike price, you can exercise then. If it never does, they expire worthless, with no tax consequence for letting them go.