What Happens to Stock Options in an IPO: Taxes, Lock-Up, and AMT

When your company goes public, your employee stock options don’t automatically pay out. What happens to stock options in an IPO is that your shares become claims on a publicly traded stock with a real market price, your vesting schedule generally keeps running as written, a lock-up period of roughly 180 days blocks you from selling, and your tax outcome depends on whether you hold incentive stock options (ISOs) or non-qualified stock options (NSOs) and how you time your exercise and sale. Handled well, the difference between the best and worst tax outcomes on a large grant can run into tens of thousands of dollars.

What Actually Changes on IPO Day

Going public creates a market price for your company’s shares. That’s the change. Your options don’t convert into cash, they don’t vest faster by default, and they don’t disappear. They become options on a stock that now has a daily quoted value, which means the spread between the market price and your strike price is finally something you can measure precisely.

Most options continue vesting on their original schedule after the IPO. Nothing about going public automatically changes the timeline in your grant agreement. What can change it is an acceleration clause, and not every company includes one. Single-trigger acceleration activates on the IPO alone, vesting some or all unvested options 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 grant has acceleration language, read it before the IPO. Single-trigger acceleration can interact badly with the ISO annual limit described below, silently converting ISOs to NSOs with no way to undo it after the fact.

The 180-Day Lock-Up

Even after the IPO, you almost certainly cannot sell your shares right away. IPO underwriters require company insiders to sign a lock-up agreement preventing sales for a set period after the offering. The most common lock-up is 180 days.¹ The purpose is to prevent a wave of selling that would tank the share price right after the company starts trading.

Some lock-ups include early release provisions. These might allow non-executive employees to sell a small percentage of shares on the first trading day, or release a portion of locked-up shares if the stock price stays above a threshold (commonly 20% to 50% above the IPO price) for a sustained number of trading days. Other agreements stagger releases around earnings announcements. Read your specific terms; the 180-day standard isn’t universal.

ISOs or NSOs: The Fork That Drives Your Tax Bill

Every employee stock option falls into one of two categories: ISOs or NSOs. Both give you the right to buy company shares at a fixed strike price. What differs is the tax treatment.

ISOs qualify for preferential tax treatment but come with strict rules. The option can only go to an employee, the strike price must be at least equal to fair market value on the grant date, the option cannot be exercised more than 10 years after grant, and it isn’t transferable except through a will.² NSOs have none of these restrictions. Companies can grant them to contractors, board members, and consultants at whatever strike price they choose. That flexibility comes at a cost: NSOs get no special tax deferral.

Your grant documents will say which type you have. If you have a mix, treat them separately when you plan.

How NSOs Are Taxed

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 you recognized at exercise. When you sell, any difference between the sale price and that basis is a capital gain or loss. Hold for 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, then capital gains tax on any additional appreciation.

How ISOs Are Taxed, and the AMT Trap

ISOs don’t trigger ordinary income tax or payroll taxes when you exercise. That’s the headline benefit. Your regular-tax basis is simply the strike price, and no withholding happens at exercise. Your employer files Form 3921 with the transaction details you’ll need for your return.³

The catch is the Alternative Minimum Tax. The AMT is a parallel calculation that adds certain items back into income so higher earners can’t cut their liability too far. The ISO spread at exercise is one of those add-back items.⁴ You calculate tax both ways 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 at $500,000 and $1,000,000 respectively.⁵ A large ISO exercise at IPO prices can push the spread well past the exemption and produce a substantial AMT bill. The partial offset: AMT paid on ISO exercises creates an AMT credit you can carry forward against regular tax in future years when you don’t owe AMT.

Qualifying and Disqualifying Dispositions

To get the full ISO benefit, you must hold the stock for at least two years from the option’s grant date and at least one year from the exercise date.² A sale meeting both is a qualifying disposition, and the entire gain is taxed at long-term capital gains rates.

For 2026, those 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.⁶ Against ordinary rates that reach 37%, the gap is meaningful on a large gain.

Selling before either holding period ends is a disqualifying disposition. The spread at exercise (or the actual gain, if smaller) is retroactively taxed as ordinary income. Any profit above the spread is capital gain. The trade-off: a disqualifying disposition eliminates the AMT adjustment for that exercise, which can occasionally make it the better financial choice. Run both scenarios before selling.

The $100,000 ISO Annual Limit

There’s 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.² Value is measured as of the grant date, and options apply in the order they were granted.

This limit bites at IPO time. If your grant includes acceleration that vests multiple years of options at once, you can blow through the cap in a single year. The options above the cap lose ISO treatment and become NSOs, meaning ordinary income tax on the spread at exercise. Knowing this before the IPO closes gives you time to plan around it.

How to Pay for the Exercise

Exercising means paying the strike price and, for NSOs, covering tax withholding. Post-IPO, three methods are usually available through your company’s stock plan administrator.

Cash exercise. You pay the strike price and any tax out of pocket, and keep every share. This is the choice when you want to hold the stock and start the long-term capital gains clock.
Sell-to-cover. The broker sells enough shares to cover the strike price and tax withholding, then deposits the rest into your account. You hold fewer shares but need no upfront cash.
Cashless exercise, also called same-day sale. The broker sells all the shares immediately and delivers net cash after the strike price and taxes. Simplest, no capital required, no shares left.

For NSOs, the brokerage handles income tax and payroll withholding at exercise. For ISOs, there is generally no withholding, but you still need to plan for the AMT bill that lands at filing. Any method you choose leaves your shares subject to the lock-up.

Estimated Tax and the Net Investment Income Tax

A large ISO exercise creates an estimated tax problem. The IRS expects taxes paid throughout the year, not in a lump sum at filing. If withholding doesn’t cover your liability and you expect to 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 AMT can be significant. One practical workaround is to file an updated W-4 asking your employer to increase withholding on your regular paycheck.⁷

Capital gains on the sale may also trigger the Net Investment Income Tax, a 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 for joint filers).⁸ Those thresholds aren’t indexed to inflation, so a large post-IPO sale can easily cross them.

If You Made a Section 83(i) Deferral, the IPO Ends It

Some employees at qualifying private companies used a Section 83(i) election to defer tax on exercised stock options for up to five years. The election is available only where at least 80% of U.S. employees receive equity grants, and it excludes executives, 1% owners, and the four highest-paid officers.⁹

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.⁹ The deferred income becomes taxable the year the company goes public, even though the lock-up prevents you from selling shares to pay the bill. If you relied on an 83(i) deferral, plan for that cash squeeze before the IPO date is set.

If You’re an Affiliate: Rule 144 and Blackouts

Once the lock-up expires, most employees can trade freely. Officers, directors, and large shareholders (collectively called affiliates under securities law) face permanent restrictions under SEC Rule 144. The volume limit caps sales in any three-month period at the greater of 1% of the company’s outstanding shares or the average weekly trading volume over the preceding four weeks. Any sale over 5,000 shares or $50,000 in value during a three-month window also requires filing a Form 144 notice.¹⁰

Many affiliates set up a Rule 10b5-1 trading plan to work around these limits. The plan commits to buying or selling specific numbers of shares at preset prices or dates, and must be established before the insider becomes aware of material nonpublic information.¹¹ Companies also impose internal blackout periods around quarterly earnings that block employee trading regardless of affiliate status.

If Your Options Are Underwater

Not every IPO makes employees rich. If the stock trades below your strike price after listing, your options are underwater and have no intrinsic value. Exercising would mean paying more per share than the market will pay you back.

You don’t have to do anything. Underwater options cost nothing to hold, and prices can recover. Options remain valid until they expire, which for ISOs is a maximum of 10 years from the grant date.² If the price climbs above your strike price later, you can exercise then. If it never does, the options expire worthless, with no tax consequence for letting them go.

1
Investor.gov. Initial Public Offerings – Lockup Agreements
2
Office of the Law Revision Counsel. 26 USC 422 – Incentive Stock Options
3
Internal Revenue Service. Instructions for Forms 3921 and 3922
4
Office of the Law Revision Counsel. 26 USC 56 – Adjustments in Computing Alternative Minimum Taxable Income
5
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
6
Tax Foundation. 2026 Tax Brackets and Federal Income Tax Rates
7
Internal Revenue Service. Estimated Taxes
8
Office of the Law Revision Counsel. 26 USC 1411 – Imposition of Tax
9
Office of the Law Revision Counsel. 26 USC 83 – Property Transferred in Connection With Performance of Services
10
U.S. Securities and Exchange Commission. Rule 144 – Selling Restricted and Control Securities
11
eCFR. 17 CFR 240.10b5-1 – Trading on the Basis of Material Nonpublic Information in Insider Trading Cases