ISO AMT (Alternative Minimum Tax on Incentive Stock Options)

Incentive Stock Options (ISOs) get favorable tax treatment if you hold the shares long enough — but the Alternative Minimum Tax (AMT) can hit you in the year of exercise, even though no shares have been sold.

The mechanics

When you exercise an ISO:

• For regular tax purposes, there is no immediate income
• For AMT purposes, the spread (FMV at exercise minus strike price) is an AMT preference item

If your AMT exceeds your regular tax, you pay the difference. This often happens when employees exercise large ISO grants on a paper-rich, cash-poor balance sheet.

Disqualifying disposition

If you sell the shares before holding for 1 year from exercise AND 2 years from grant, the sale is a "disqualifying disposition." The spread becomes ordinary income, eliminating AMT exposure but also losing long-term capital gain treatment.

Strategic exercise

Common planning moves:

• Exercise early in the year and decide later in the year whether to disqualify
• Exercise in years when income is otherwise low (sabbatical, job change)
• Exercise small batches each year to stay below the AMT crossover
• Use AMT credit in future years when regular tax exceeds tentative AMT

AMT credit recovery

Pre-paid AMT typically creates a refundable AMT credit that can offset future regular tax. The math improves over time, but the cash drag in the exercise year is real.