If you paid AMT in a prior year due to exercising ISOs, you may be eligible to reclaim that as a credit this year. See our overview of the AMT credit if you're not sure whether you qualify before proceeding.

Two things to confirm first:

  • You paid AMT in a previous year (specifically, your AMT exceeded your regular tax)
  • You do not also owe AMT in the current filing year

If both are true, here's how to claim it.

Step 1: Locate Your Old IRS Form 6251

Form 6251 is the form you filed in the prior year when you calculated and paid AMT. You'll need the numbers from this form to complete Form 8801.

If you used tax software (TurboTax, H&R Block, FreeTaxUSA, etc.), you can pull it up from your prior year's saved return. You can also find a blank copy on the IRS website to familiarize yourself with the layout.

Step 2: Fill Out Form 8801

Navigate to your tax software and search for "AMT Credit" — most major programs will surface Form 8801 directly.

You'll be asked a series of questions. All you need to do is carry over the relevant numbers from your prior year's Form 6251. The instructions tell you exactly which rows to reference.

One thing to note: tax software typically asks only about exclusion items in this section — not about ISO exercises. That's intentional. ISO exercise spreads are deferral items, which do qualify for the AMT credit, and the software handles them separately via the Form 6251 inputs. You're in the clear.

At the end, the software will combine your Form 8801 inputs with the rest of your tax return and calculate your final AMT credit amount. The credit is applied dollar-for-dollar against your tax owed.

Step 3: Track What You Used and What's Left

The IRS doesn't maintain a running balance of your AMT credit for you. After filing, note:

  • How much credit you started with
  • How much you applied this year
  • How much carries forward

Keep this alongside your tax returns and original ISO exercise documentation. If you're ever audited, this is your evidence.

That's It

The AMT credit is one of the most overlooked tax benefits for people who've exercised ISOs. If you've paid AMT in prior years and aren't in an AMT-owing year now, make sure you're claiming it.