Incentive stock options (ISOs) get special treatment: no regular income tax when you exercise, and long-term capital gain treatment on the whole gain if you meet the holding periods. The catch is the alternative minimum tax, which counts the paper gain at exercise as income.
How ISOs are taxed
- Grant and vest: no tax.
- Exercise: no regular income tax, but the spread between the exercise price and the market value is an AMT adjustment.
- Sale: if you sell at least two years after grant and one year after exercise, the entire gain over your exercise price is long-term capital gain. That's a qualifying disposition.
Why exercising can trigger AMT
AMT is a parallel tax system with its own exemption and rates. When you exercise and hold ISOs, the spread is added to your AMT income. If it's large enough, your AMT exceeds your regular tax and you pay the difference, even though you haven't sold a share or received any cash.
Beginning in 2026, the AMT exemption phases out starting around $500,000 of income for single filers and $1 million for joint filers, and it phases out faster than before. Higher earners can hit AMT with a smaller exercise than in recent years.
Strategies that reduce the risk
- Find your AMT headroom. A projection shows how much spread you can add this year before AMT kicks in. Exercising up to that amount each year spreads the exposure across years.
- Exercise early in the year. Exercising in January gives you almost a full year to watch the stock. If it falls, selling in the same calendar year turns it into a disqualifying disposition and eliminates the AMT adjustment.
- Exercise when the spread is small. At early-stage companies, exercising soon after grant, sometimes with an 83(b) election for early-exercise plans, can keep the AMT spread low.
- Plan a same-day sale for some shares. Selling some shares immediately creates ordinary income but provides cash to cover tax on the shares you keep.
The AMT credit
AMT paid because of ISO exercises generally creates a minimum tax credit you can use in future years when your regular tax exceeds your AMT, often in the year you sell. Track it carefully. Credits from earlier years are easy to lose if they aren't carried forward on each return.
Disqualifying dispositions
If you sell before meeting both holding periods, the spread at exercise becomes ordinary income, reported on your W-2, and any further gain is capital gain. It isn't always a mistake. Selling early can be the right choice when the stock is volatile or a large share of your net worth.
State considerations
California has its own AMT, and both California and Oregon tax option income based on where you worked between grant and vest or exercise. If you moved during that period, part of the income may still be taxable in the state you left. Washington has no income tax, but its capital gains tax can apply to large long-term gains when you sell.
The bottom line
ISOs reward planning. A multi-year exercise schedule built around your AMT headroom, your company's outlook and your cash needs can capture most of the long-term gain benefit without an unaffordable tax bill.
This article is general information, not tax, legal or investment advice for your situation. Rules and thresholds change, so please talk with a qualified advisor before acting.
