ISO Exercise - Form 3921 vs. AMT

cr9999 — Mon, 23 Feb 2026 14:35:42 GMT

I entered the 3921 form I received for an ISO exercise (did not sell) in the Investment Income section as prompted. Do I need to enter the cost basis info again in the "AMT" section later (under Other Tax Situations when it asks about any uncommon situations), or would this be double-counting the same exercise?

I believe it is double counting, as the number in the summary section titled "ISO Exercise and Hold" is showing 2 times what it should be, but I just want a sanity check if possible.

For example, ISO Exercise and Hold amount should be 30k (based on the calculation of market price - grant price * shares exercised) but shows 60k. When I remove the info I manually input into the AMT section in "Other Tax Situations" section at the end, it reverts to 30k, which aligns with what's on the 3921 forms.

Re: ISO Exercise - Form 3921 vs. AMT

MaryK4 — Sat, 18 Mar 2023 23:12:41 GMT

Yes, if you entered the information in both sections, it will double count the income. You will need to remove the information in one section.

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ISO Exercise - Form 3921 vs. AMT

Re: ISO Exercise - Form 3921 vs. AMT