Incentive stock options and the alternative minimum tax

How it works

When the shares are held at least two years from the grant and one year from the exercise, the whole gain at sale is a long term capital gain and no wages are reported, which is the qualifying disposition. Selling sooner is a disqualifying disposition, and the spread at exercise becomes ordinary wage income in the year of sale. The catch is the alternative minimum tax, a parallel tax with its own exemption of this year's official amt exemption single (not yet verified here; see the official source below) for a single filer and its own rates, which counts the exercise spread as income in the year of exercise even though nothing was sold. A worker who exercises a large block and holds can owe alternative minimum tax on paper gains, and if the stock then falls, the tax was paid on value that vanished.

What it gives

A qualifying disposition turns the whole gain, from the option price to the sale price, into a long term gain.

No tax is withheld or owed under the regular system at exercise.

Alternative minimum tax paid on the spread comes back as a credit in later years, in many cases.

What it costs, or where the catch is

A large exercise and hold can trigger alternative minimum tax on gains that exist only on paper.

Shares that fall after exercise leave the tax paid and the gain gone.

The holding periods for the long term treatment are strict, and a sale a day early turns the spread into wages.

A worked example

Amara exercises incentive stock options on 2,000 shares at $10 when the stock is $40, paying $20,000 for shares worth $80,000. The $60,000 spread, which is $80,000 minus $20,000, is income for the alternative minimum tax. With her other income, that pushes her into owing about $14,000 of alternative minimum tax in April with no shares sold. She holds the required periods and sells at $55 two years later for a long term gain of $90,000 over her $20,000 cost.

Where it goes wrong

The common miss is exercising a large block late in the year and holding into the next, which fixes the alternative minimum tax bill at a price the stock may not keep.

Who confirms it for you

For your own numbers, a CPA or enrolled agent. This page explains how the rule works for people in general; it does not know your situation and does not tell you what to do.

The official source

IRS Tax Topic 427, Stock options. Every figure that changes by year comes from the site's rules table, which the watcher checks against the official page on a schedule; where a figure is not yet verified, this page says so instead of printing a number.