ISO Qualifying vs Disqualifying Disposition: The 1-Year and 2-Year Clocks

A senior engineer at a cloud security startup exercised 8,000 ISOs in January 2024 with a strike of $3.10 and a 409A of $47. The bargain element was $351,200. She paid $42,000 of AMT on the 2024 return and held the shares, planning to sell in January 2026 to get long-term capital gain treatment. The company IPO’d in February 2025 at $62. In November 2025 a recruiter came knocking with an offer that required a quick start. She moved jobs and sold her shares in December 2025 to clean up her holdings. The stock sold at $95.

The December sale was a disqualifying disposition. It fell short of both clocks: the one-year post-exercise holding requirement (satisfied only just, in January 2025) and the two-year post-grant requirement (the grant was made in February 2023, so the two-year clock also ran). Wait, the grant was February 2023, meaning two years post-grant elapsed in February 2025. The exercise was January 2024, meaning one year post-exercise elapsed in January 2025. By December 2025, both clocks had run.

So why is this a disqualifying disposition? It is not. The December 2025 sale is a qualifying disposition. The entire gain from $3.10 strike to $95 sale is long-term capital gain. The distinction between qualifying and disqualifying dispositions rests entirely on these two clocks, and running both matters more than any other single rule in the ISO universe.

The two clocks

IRC §422(a) defines a qualifying ISO disposition as one meeting both:

The holding period beginning on the date of exercise lasts at least one year, and
The holding period beginning on the date the option was granted lasts at least two years.

A disposition that fails either test is a disqualifying disposition.

“Disposition” under §422 means a sale, exchange, gift, or transfer of legal title. It does not include a transfer to a spouse, a transfer incident to divorce, or a transfer between a decedent and an estate. It does include a gift to a non-spouse, which is a common disqualifying event that surprises planners who assume charitable transfers are tax-neutral.

Why two clocks

The two-clock structure is designed to distinguish true long-term ownership from opportunistic exercise-and-flip transactions. A one-year clock alone could be gamed by exercising early in the grant period. A two-year grant clock alone could be gamed by holding the option itself rather than exercising. Both together require the employee to commit capital through exercise and to let it appreciate over meaningful time.

Qualifying disposition: the tax picture

If both clocks run, the disposition is qualifying. The entire gain from strike price to sale price is long-term capital gain. Federal tax rates are 0%, 15%, or 20% depending on taxable income. The 3.8% NIIT adds on top for high earners.

There is no ordinary income on the sale under §422. The compensation element that would have been ordinary under a disqualifying disposition is absent.

The AMT adjustment

A qualifying disposition of stock that was subject to AMT at exercise produces an AMT basis adjustment at the sale. Regular-tax basis is the strike price; AMT basis is the strike price plus the bargain element (because AMT already taxed the bargain element). On sale, regular-tax gain is sale price minus strike; AMT gain is sale price minus AMT basis.

Suppose strike $3.10, exercise-date FMV $47, sale price $95. Shares: 8,000.

Calculation	Regular tax	AMT
Proceeds	$95 × 8,000 = $760,000	$760,000
Basis	$3.10 × 8,000 = $24,800	$47 × 8,000 = $376,000
Gain	$735,200	$384,000

The regular-tax gain of $735,200 is long-term capital gain taxed at 20% + 3.8% NIIT = 23.8%, or $175,008. The AMT gain of $384,000 factors into the AMT calculation for the year of sale. Typically, in a year with $735K of long-term gain and modest other income, regular tax exceeds tentative minimum tax, so the AMT adjustment reduces (or eliminates) AMT and triggers AMT credit recovery from prior-year AMT paid.

Disqualifying disposition: the tax picture

A disqualifying disposition produces ordinary wage income equal to the lesser of:

The bargain element at exercise (FMV at exercise minus strike), or
The actual gain (sale price minus strike).

If the stock appreciated between exercise and sale, the ordinary income portion is capped at the bargain element at exercise. The gain above that is capital gain, short-term or long-term depending on how long the shares were held.

If the stock depreciated, the ordinary income portion is the actual gain (which may be zero or even negative).

A worked example

Same facts as above: strike $3.10, exercise FMV $47, sale $95, 8,000 shares. Assume sale before clocks run.

Bargain element at exercise: $47 - $3.10 = $43.90 × 8,000 = $351,200 ordinary income
Actual gain: $95 - $3.10 = $91.90 × 8,000 = $735,200
Ordinary income portion = min($351,200, $735,200) = $351,200
Capital gain portion = $735,200 - $351,200 = $384,000

The $351,200 is reported as wages on the W-2 in the year of disposition, subject to federal income tax at ordinary rates (up to 37%). The $384,000 is capital gain, short-term (taxed as ordinary) or long-term depending on holding period from exercise.

For a single filer with $420,000 of other income, the ordinary $351,200 is taxed at roughly 35% to 37%, or about $126,000. The capital gain of $384,000 at long-term rates (if held more than one year from exercise) is taxed at 20% + 3.8% NIIT = 23.8%, or $91,392. Total federal tax: about $217,000.

The AMT reversal

When a disqualifying disposition occurs, the AMT preference is reversed. The original AMT paid in the year of exercise was based on the assumption of qualifying treatment. A subsequent disqualifying disposition reverses that treatment.

The mechanical effect on Form 6251 in the year of sale is to report a negative adjustment equal to the excess, if any, of the amount treated as ordinary income under the disqualifying disposition over the regular-tax basis. This typically eliminates the AMT adjustment for the year of sale.

For AMT paid in the year of exercise, the AMT credit (Form 8801) is available against future regular tax, but only to the extent regular tax exceeds tentative minimum tax in the year of use. A disqualifying disposition produces a surge of ordinary income that raises regular tax, which can accelerate AMT credit recovery.

Which path produces more after-tax value

The comparison depends on three variables: the marginal ordinary tax rate, the effective AMT rate, and the appreciation from exercise to sale.

Scenario A: Strike $3.10, exercise FMV $47, sale price $95

Qualifying (both clocks run):

Long-term capital gain: $735,200 at 23.8% (20% + 3.8% NIIT) = $175,008
AMT at exercise (approximately): $90,000 (paid in exercise year)
AMT credit recovery: approximately $90,000 over future years
Net federal tax: approximately $175,000

Disqualifying (clocks not run):

Ordinary income: $351,200 at 37% = $130,000
Capital gain: $384,000 at 23.8% (if held more than 1 year from exercise) = $91,400
Total federal tax: approximately $221,400

The qualifying path is about $46,000 cheaper in this scenario.

Scenario B: Strike $3.10, exercise FMV $47, sale price $28 (stock declined)

Qualifying (both clocks run):

Long-term capital gain: $24.90 × 8,000 = $199,200 at 23.8% = $47,400
AMT at exercise (approximately): $90,000 (paid, likely partial recovery due to long-term holding)

Disqualifying (clocks not run):

Ordinary income: min(bargain element, actual gain) = min($351,200, $199,200) = $199,200 ordinary
Capital gain: none
Federal tax: $199,200 at 37% = $73,700
AMT at exercise reversed, credit not applicable because no AMT in year of exercise if disqualifying within same year

For a same-year disqualifying disposition (exercise and sell within the calendar year), no AMT is paid because the preference is absorbed by the ordinary income. That saves the AMT prepayment.

Scenario C: Same-year exercise-and-sell

A same-year exercise-and-sell is always a disqualifying disposition. The tax picture is:

Ordinary income equal to actual gain (no AMT preference)
No long-term capital gain
No AMT credit produced or used

This is the cleanest path when the intent is immediate liquidation. It skips the AMT quagmire and produces predictable ordinary-income treatment.

The practical decision tree

The decision logic for any ISO exercise reduces to:

Do I want to hold for the qualifying clocks? If yes, exercise-and-hold and plan for AMT.
Do I want to sell immediately? If yes, exercise-and-sell in the same year (disqualifying, but no AMT paid).
Is the bargain element large enough to create material AMT exposure I can’t fund?
Has the stock moved against me such that holding through the clocks is not worth the concentration risk?

The AMT/ISO calculator lets you compare the two paths with specific numbers.

Edge cases

Gift to a non-spouse before clocks run

A gift to a child, parent, or friend before the one-year and two-year clocks have both run is a disqualifying disposition. The employee recognizes ordinary income on the bargain element. The recipient’s basis is the employee’s basis plus the ordinary income reported.

Death before clocks run

Death is generally not a disposition under §422. The shares pass to the estate or heir with a step-up in basis to fair market value at date of death (IRC §1014). The clocks effectively reset for the heir, and the ordinary-income trap is eliminated by the step-up.

Exchange in a tax-free reorganization

An ISO exchanged for a successor company’s stock in a tax-free merger is generally not a disposition if the §424(a) requirements are met. The clocks continue to run on the successor stock.

Frequently asked

Do both clocks have to run, or is it okay if just one runs?

Both must run. A disposition meeting only the one-year post-exercise test but not the two-year post-grant test is still disqualifying.

What if I exercise early in the grant period?

The two-year post-grant clock starts at grant and ends two years later. Exercising early does not change the grant date. Early exercisers (through an 83(b) election on ISOs, if the plan permits) may reach the two-year post-grant clock before they reach the one-year post-exercise clock. Both clocks still apply.

Does a Rule 10b5-1 plan sale count as a disqualifying disposition?

A sale under a 10b5-1 plan is a disposition like any other. If the sale occurs before both clocks run, it is disqualifying regardless of the plan’s existence.

Can I partially disqualify?

Yes. A disposition of some shares before the clocks run is disqualifying as to those shares. Shares held longer become qualifying when the clocks run on them. Specific-lot identification matters.

What if the stock drops below the strike price?

If you let the ISOs expire without exercising, nothing happens. If you exercised and the stock drops below strike, you are underwater. Selling at a loss more than one year from exercise produces long-term capital loss. Selling within one year of exercise produces ordinary income limited by the actual gain (which is negative), so you essentially reverse the bargain element and generate a capital loss.

Before you exercise, run the qualifying and disqualifying paths side by side in the AMT/ISO calculator.