Incentive Stock Options and the AMT: The Exercise Strategy That Avoids the Trap

Key takeaways

ISOs can be taxed entirely at capital gains rates if you hold shares two years from grant and one year from exercise, but the exercise spread is an AMT adjustment in the exercise year.
In 2026 the AMT exemption is $90,100 single and $140,200 joint, phasing out above $500,000 and $1,000,000 of AMT income.
Exercise up to the "AMT crossover," the amount of spread you can take before AMT exceeds regular tax, each year.
AMT paid on ISO exercises generates a credit that comes back in later years; it's a prepayment, not a lost tax, but the cash flow is real.

Incentive stock options are the most tax-favored form of equity compensation, and the one most likely to produce a nasty surprise. The favorable treatment is real: exercise, hold, and the entire gain from grant price to eventual sale price can be a long-term capital gain. The surprise is the alternative minimum tax, which taxes the paper gain at exercise even though no cash has come in. We've watched people exercise a big ISO block in a rising market, hold, and then owe a six-figure AMT bill on a gain that had already evaporated by April.

The strategy below exists so that doesn't happen to you.

How ISOs are taxed

At exercise, you pay the strike price and receive shares. For regular income tax, nothing happens. For AMT, the spread (fair market value at exercise minus strike price) gets added to your income.

If you sell the shares after holding them at least two years from the grant date and one year from the exercise date, the sale is a "qualifying disposition," and the entire gain from strike price to sale price is a long-term capital gain, taxed at 15% or 20% plus the 3.8% surtax.

Sell earlier and it's a "disqualifying disposition": the spread at exercise (or the actual gain if less) becomes ordinary income in the year of sale, and any further gain is capital gain. No AMT adjustment in that case, because the income is recognized for regular tax instead.

How the AMT works in 2026

The alternative minimum tax is a parallel calculation. You compute AMT income by adding back certain items to regular taxable income, the ISO spread among them, subtract an exemption, and apply a rate of 26% up to a threshold (about $244,500 for joint filers in 2026) and 28% above. If the AMT calculated this way exceeds your regular tax, you pay the difference as AMT.

The 2026 exemption is $90,100 for single filers and $140,200 for joint filers, and it phases out at 50 cents per dollar of AMT income above $500,000 (single) and $1,000,000 (joint), a faster phase-out than before 2026. The 2017 law raised the exemption and the phase-out thresholds substantially, and the 2025 law made the higher exemption permanent while resetting the phase-out thresholds to $500,000 and $1,000,000 with a steeper 50% phase-out, so far fewer people hit AMT from ordinary deductions than a decade ago. ISO exercises are still the most common trigger.

The crossover

Because AMT is only owed to the extent it exceeds regular tax, there's a certain amount of ISO spread you can absorb each year before any AMT is due. Above that amount, every additional dollar of spread costs roughly 26 to 28 cents of AMT. That amount is the AMT crossover, and it's the key number in any ISO exercise plan.

The crossover depends on your regular income, deductions, filing status, and state (no Florida income tax matters here, because state tax is an AMT add-back for people who itemize). For a joint filer with $250,000 of wages and the standard deduction, the crossover might be on the order of $100,000 to $150,000 of spread. For a single filer with $150,000 of wages it's smaller. The number changes every year and has to come out of a projection, not a guess.

The exercise strategy

Exercise early in the year, up to the crossover. Spread the exercises across tax years so each year's spread stays under the crossover, and no AMT is owed at all. Exercising in January gives you the longest look at the stock before the year ends.

Reassess before year end. If the stock has fallen since exercise, a disqualifying disposition before December 31 (selling the shares) wipes out the AMT adjustment and replaces it with ordinary income on the actual, smaller gain. This is the escape hatch the six-figure-AMT-bill people never used. It costs the long-term treatment on those shares. It also keeps you from paying tax on a gain that no longer exists.

Hold what remains past the two dates. Shares exercised under the crossover and held for the required periods produce the full capital gains benefit.

Use the credit. If AMT is paid in a year, it generates a minimum tax credit that reduces regular tax in future years when regular tax exceeds AMT, typically when the shares are finally sold. So AMT is largely a timing cost. But the cash has to be there when it's due.

When to exercise and sell immediately

Sometimes the right move is a same-day exercise and sale, accepting ordinary income treatment. The reasons: the position would otherwise become a dangerous concentration; you need the cash; the company's outlook is shaky; or the spread is so large the AMT would eat the benefit of holding. Ordinary income at 35% on a certain gain can beat capital gains at 20% on a gain that might not survive the holding period.

Private company ISOs

For employees of private companies, exercising has an extra cost: the cash for the strike price and any AMT, with no market to sell into. The 409A valuation sets the spread for AMT purposes. Exercising early, when the spread is small, can lock in the holding period cheaply; an 83(b) election on early-exercised unvested shares starts the clocks immediately. If the shares qualify as QSBS, holding five years can exclude the gain entirely; see QSBS after the 2025 law change. And before a liquidity event, our startup equity checklist covers the sequencing.

The $100,000 rule

Options that become exercisable in a single year with a total strike value above $100,000 are treated as non-qualified options for the excess. Grants at fast-growing companies blow through this without anyone noticing, and the excess is taxed as ordinary income at exercise with withholding. The grant paperwork should say which portion is ISO and which is NSO; the difference matters.

How we plan it

Each client with ISOs has an exercise schedule: the crossover for the year computed from the projection, the exercise amount and timing, the year-end check against the current price, and the sale plan for shares that reach their holding periods. AMT paid gets tracked as a credit and recovered in the sale years. It's part of equity compensation planning, and we rebuild it every January.

Frequently asked questions

Do I owe AMT if I exercise and sell in the same year?

No. A same-year sale is a disqualifying disposition; the spread is ordinary income for regular tax, and there's no separate AMT adjustment.

Can I deduct the strike price?

The strike price is your basis in the shares for regular tax. For AMT, your basis is the fair market value at exercise, which is why the eventual sale produces a smaller AMT gain and lets the credit come back.

How long does the AMT credit take to recover?

It depends on the gap between regular tax and AMT in later years. Selling the shares in a qualifying disposition usually creates a large regular-tax gain and a small AMT gain, and that's when most of the credit gets used.

Is it better to have ISOs or RSUs?

ISOs offer more tax upside and more risk; RSUs are simpler and always taxed as wages at vesting. Neither is better in the abstract. What matters is the plan for each; our RSU guide covers the other side.

Joseph G. Valerio, CFP®, EAFounder and Lead Advisor at Valerio Wealth Management, a fee-only, fiduciary virtual family office in Miami, Florida. One advisor, credentialed in both financial planning and federal tax. About Joseph

This article is general education, not individualized advice, and it is not tax, legal, or accounting advice. Figures reflect federal law for the year stated and can change. Valerio Wealth Management does not prepare or file tax returns. Speak with a qualified professional about your own situation before acting.