Statutory vs Non-Statutory Stock Options: Exercise, Sale, and AMT

Statutory stock options and non-statutory stock options differ mainly in how the IRS taxes them. Statutory options, which for most employees means incentive stock options (ISOs), can let your entire profit be taxed at long-term capital gains rates if you follow strict holding rules. Non-statutory stock options (NSOs) tax the spread at exercise as ordinary income and only tax the gain that accrues afterward as capital gain. That one distinction drives almost every other rule that separates the two.

Who Can Receive Each Type

NSOs are the default. Any option that doesn’t meet the specific Internal Revenue Code requirements for special tax treatment is automatically an NSO. Companies can grant NSOs to employees, board members, consultants, and other independent contractors, and the terms — duration, vesting, exercise price — are whatever the option contract says.

ISOs are far more restricted. They can only go to common-law employees of the company or its parent or subsidiary, and the option agreement has to follow the rules in IRC Section 422.¹ The exercise price must be at least the fair market value of the stock on the grant date. The option can’t run longer than ten years. A written plan approved by shareholders must specify the total shares available and which employees qualify. None of that applies to NSOs.

What Happens at Grant and Vesting

Neither type produces a tax bill when the option is granted or when it vests. The IRS defers taxation because most stock options don’t have a readily ascertainable fair market value at the time of the grant.² Vesting turns your option from a contingent right into an enforceable one, but the IRS doesn’t treat that as income. You owe nothing until you exercise or sell.

A narrow exception exists for options that trade on an established market, where fair market value is readily ascertainable. Those would be taxed at grant. In practice almost no employee stock options fall into this category.

How Each Is Taxed at Exercise

The “spread” at exercise is the difference between what you pay (the exercise price) and what the stock is worth on that date. This is where the two option types diverge.

NSO Exercise: Ordinary Income Right Away

When you exercise an NSO, the spread is taxed as ordinary income in the year of exercise, whether you sell the stock immediately or keep holding it.² Your employer reports the income on your W-2 and withholds federal income tax at the 22% supplemental wage rate, or 37% for amounts over $1 million in a calendar year. The spread also carries Social Security tax (6.2% on wages up to $184,500 in 2026) and Medicare tax (1.45%, plus an additional 0.9% on wages above $200,000).³

Your cost basis in the acquired shares equals the exercise price plus the ordinary income you already recognized. If you paid $10 per share and the stock was worth $50 at exercise, your basis is $50 per share, because you already paid tax on that $40 spread. Any future gain or loss starts from that $50 baseline.

The employer gets a tax deduction equal to the spread in the year of exercise. That corporate deduction is one reason many companies prefer NSOs for highly compensated executives, where the spread will be large.

ISO Exercise: No Regular Income Tax, but Watch the AMT

Exercising an ISO does not trigger ordinary income tax. The spread is not on your W-2, and no income tax or payroll tax is withheld.¹ You only need cash for the exercise price. The employer, in turn, gets no tax deduction.⁴

The spread isn’t invisible to the IRS, though. It counts as a positive adjustment when calculating your Alternative Minimum Tax. If the adjustment pushes your AMT liability above your regular tax liability, you owe the difference. For 2026, the AMT exemption is $90,100 for single filers and $140,200 for married couples filing jointly, with phaseouts beginning at $500,000 and $1,000,000 respectively.⁵ AMT rates run 26% on the first $244,500 of AMT income above the exemption and 28% above that.

A large ISO exercise burns through the exemption fast. This produces one of the most common tax surprises in equity compensation: you exercised ISOs, didn’t sell any stock, and now owe a five- or six-figure AMT bill the following April. The stock may have even dropped between the exercise date and the tax filing date, so you’re paying tax on a gain that no longer exists in your brokerage account. If you paid AMT, you can claim an AMT credit in future years when your regular tax exceeds the AMT calculation, but recovery can take several years.

How Each Is Taxed When You Sell the Stock

The sale is where the full picture comes together. NSOs are simple. ISOs depend on how long you held the shares.

Selling NSO Shares

You already paid ordinary income tax on the spread at exercise, so your cost basis is the fair market value on the exercise date. Anything after that is capital gain or loss. Hold for more than a year after exercise and the gain qualifies for long-term capital gains rates. Sell inside a year and it’s short-term, taxed at ordinary rates.⁶

For 2026, long-term capital gains are taxed at 0% for single filers with taxable income up to $49,450 ($98,900 for married filing jointly), 15% up to $545,500 ($613,700 jointly), and 20% above those thresholds. High earners face an additional 3.8% net investment income tax on capital gains once modified adjusted gross income exceeds $200,000 single or $250,000 joint.⁷ The effective top federal rate on long-term gain is 23.8%.

Selling ISO Shares: Qualifying vs. Disqualifying Dispositions

The whole point of ISOs is the qualifying disposition. To qualify, you must hold the shares at least two years from the grant date and at least one year from the exercise date.¹ Both conditions have to be met. When they are, the entire profit from exercise price to sale price is treated as long-term capital gain. No portion is taxed as ordinary income, and any AMT you paid at exercise starts crediting back against regular tax over time.

Sell before either holding period is done and you have a disqualifying disposition. The IRS recaptures a portion of the gain as ordinary income: the lesser of the actual profit on the sale or the spread that existed at exercise. That ordinary income appears on your W-2 for the year of the sale, but it isn’t subject to Social Security or Medicare tax. Any gain above the ordinary income portion is a capital gain. The employer picks up a corresponding deduction for the ordinary income amount.

This gets tricky in practice. Suppose you exercised ISOs when the spread was $80,000 and then the stock dropped before you sold, so your actual profit was only $30,000. The ordinary income on the disqualifying disposition would be $30,000 (the lesser of the two), not $80,000. But if you previously paid AMT on the full $80,000 spread, you’ll need to reconcile the AMT credit on your return. This multi-year, multi-form complexity is why many ISO holders end up needing professional tax help.

The $100,000 Annual ISO Limit

There’s a cap on how many ISOs can become exercisable for the first time in any calendar year. If the aggregate fair market value of the underlying stock, measured at the grant date, exceeds $100,000 in a single year, the excess options are automatically treated as NSOs.⁸ The limit applies across all plans of the employer and its related corporations.

Options granted earliest are counted first, and later grants that push you over $100,000 convert automatically. Companies with aggressive vesting schedules sometimes trigger this reclassification without meaning to, and the employee may not realize part of the ISO grant has become an NSO until tax time. No equivalent limit exists for NSOs.

What Happens When You Leave Your Job

This is where many employees quietly lose the ISO tax advantage. Under IRC Section 422, you must have been an employee continuously from the grant date until no later than three months before the exercise date.¹ If you leave your job and don’t exercise your ISOs within roughly 90 days, they convert to NSOs. The favorable tax treatment vanishes and any exercise after that window is taxed like an NSO exercise: ordinary income on the spread, payroll taxes, withholding.

Most option agreements give you a specific post-termination exercise window, often 90 days, though some companies (particularly startups) have extended this. The ISO tax treatment still expires at 90 days regardless of what the option agreement says. If your company gives you a year to exercise after leaving, you can exercise during months four through twelve, but those options will be taxed as NSOs.

Two exceptions apply. If you leave due to permanent disability, the window extends to one year. If the option holder dies, the estate or heir who inherits the option is not bound by the employment requirement, and the holding period rules for qualifying dispositions don’t apply to them either.

NSOs aren’t affected by any of this. Your post-termination exercise window for NSOs is whatever the option agreement specifies, and the tax treatment stays the same regardless of your employment status.

Quick Comparison

Who can receive them: ISOs, employees only; NSOs, anyone the company chooses to grant them to.
Tax at exercise: ISOs, no regular income tax but AMT exposure on the spread; NSOs, ordinary income on the spread plus payroll tax withholding.
Tax at sale (long hold): ISOs qualifying disposition, entire profit is long-term capital gain; NSOs, capital gain only on appreciation after exercise.
Tax at sale (short hold): ISOs disqualifying disposition, part of the profit is ordinary income; NSOs, short-term gain taxed as ordinary income.
Employer deduction: ISOs, none unless there’s a disqualifying disposition; NSOs, deduction equal to the spread at exercise.
Grant-price floor: ISOs, at least fair market value on grant date; NSOs, no statutory floor.
Annual cap: ISOs, $100,000 in stock value first exercisable per year; NSOs, no cap.
After you leave: ISOs, 90-day window before conversion to NSO treatment; NSOs, whatever the option agreement says.

Which One Is Better for You

Employees rarely get to pick which type they receive, but understanding the trade-offs helps you time your exercise and sale. ISOs make the most sense when the spread at exercise is modest relative to the AMT exemption, you can afford to hold the shares for the required periods, and you expect meaningful appreciation after exercise. The payoff is having the entire gain taxed at long-term capital gains rates instead of splitting it between ordinary income and capital gains.

NSOs are more predictable. The tax hit comes at exercise, withholding is handled by your employer, and your basis is set at fair market value. There’s no AMT calculation, no dual-basis tracking, and no risk that a disqualifying disposition wipes out months of planning. For employees at companies with volatile stock or when you need liquidity quickly, the simplicity of NSOs has real value.

From the company’s side, NSOs generate a corporate tax deduction equal to the ordinary income the employee recognizes. ISOs produce no deduction unless the employee triggers a disqualifying disposition. That’s why many companies grant NSOs to senior executives, where the deduction on a large spread can be worth millions, and reserve ISOs for employees whose expected spreads are smaller or who particularly value the capital gains treatment.

1
Office of the Law Revision Counsel. 26 USC 422 – Incentive Stock Options
2
eCFR. 26 CFR 1.83-7 – Taxation of Nonstatutory Stock Options
3
Social Security Administration. Contribution and Benefit Base
4
Office of the Law Revision Counsel. 26 USC 421 – General Rules
5
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
6
Internal Revenue Service. Topic No. 409, Capital Gains and Losses
7
Internal Revenue Service. Topic No. 559, Net Investment Income Tax
8
eCFR. 26 CFR 1.422-4 – $100,000 Limitation for Incentive Stock Options