Who needs to file Form 3921, and by when?
Your company files, not the person who exercised. Two things have to be true.
Your company is incorporated in the US
At least one person exercised Incentive Stock Options during the calendar year
Every exercise counts, whether or not the person still works there. Someone who exercised before they left is reportable in the year it happened.
The three dates
| Date | What is due |
|---|---|
| 31 January | Copy B to each person who exercised |
| 28 February | Copy A to the IRS, filing on paper |
| 31 March | Copy A to the IRS, filing electronically |
All three cover the prior calendar year. When a date lands on a weekend or a public holiday, it moves to the next business day.
Filing 10 or more information returns in total, counting W-2s and 1099s alongside your 3921s, makes electronic filing mandatory.