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Official form guide
Form 3921: Exercise Of an Incentive Stock Option Under Section 422(b)
IRS Form 3921 is used to report the exercise of an incentive stock option under section 422(b); every corporation that transfers stock on such an exercise must file. The e‑file threshold is 10 returns, effective Jan 1 2024.
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IRS Form 3921 - Exercise Of an Incentive Stock Option Under Section 422(b)
IRS Form 3921 is used to report the exercise of an incentive stock option under section 422(b); every corporation that transfers stock on such an exercise must file. The e‑file threshold is 10 returns, effective Jan 1 2024.
Risk Radar
Scan points- 1Skipping the required filing for a transfer triggers IRS penalties.
- 2Filing Form 3921 when the corporation is not required because the employee is a nonresident alien without a W‑2.
- 3Omitting the employee’s statement copy, which must be furnished to the transferee.
- 4Leaving Box 1, Box 2, or Box 3 blank, so the grant date, exercise date, or price is missing.
- 5Truncating the employee’s TIN on the form or any accompanying document, which is prohibited.
Plain English
Form 3921 tells the IRS when a company gives an employee stock after they exercise an incentive stock option. The company reports the grant date, exercise date, and price per share. It also must give a copy of the form to the employee.
Submission Date
- Filing date: 2026-02-10 16:10:39
- Preparation window: collect IDs, supporting records, and signatures in advance.
- Final review: verify names, dates, and required fields before submission.
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What this form is for
- Use this form when a corporation transfers stock to a person upon exercise of an incentive stock option described in section 422(b).
- Do not use it when the transfer arises from an employee stock purchase plan under section 423(c) or any non‑ISO transaction.
- Check Form 3922 instead when the transfer is under an employee stock purchase plan (section 423(c)).
Form selector
Use this form or another form?
Corporation records a transfer of stock acquired through an employee stock purchase plan (section 423(c))
Reporting requirement differs; 3922 covers ESPP transfers
✓ Verify plan type before filing
Employee must calculate alternative minimum tax on ISO exercise
AMT calculation for ISO exercise
✓ Confirm AMT inclusion if applicable
E‑file threshold lowered to 10 information returns
Threshold applies to all information returns including 1099 series
✓ Check total return count before e‑filing
Deadline or filing window
Not stated in the official source.
Checklist
What you need before filling it out
Box 1 – Exercise price per share
Exercise price amount · Entered by corporation on Form 3921
Box 8 – Exercise price determinability indicator
Leave blank if price fixed · Form 3921 instructions
Corporation name, address, TIN
Corporate name, address, TIN · Form 3921 header
Employee TIN
Employee’s taxpayer identification number · Form 3921 employee section
Copies B and C
Printed copies for recipient and records · Form 3921 PDF fillable copies
Before you submit
- 1Confirm the revision date reads 04/2025 on the form.
- 2Verify corporation name, address, and TIN are correct.
- 3Enter the exercise price per share in Box 1.
- 4Leave Box 8 blank if the exercise price is fixed or determinable on the grant date.
- 5Enter the employee’s name and TIN accurately.
- 6Prepare and attach Copies B and C as required.
- 7Ensure any required signature is present.
- 8Retain the original copy for corporate records.
- 9File the return by the due date for the calendar year.
- 10E‑file only if total information returns for the year are 10 or fewer.
How to file this form
- 1Gather corporation’s name, address, and TIN.
- 2Record the exercise price per share in Box 1.
- 3Leave Box 8 blank when the exercise price is fixed.
- 4Enter employee’s name and taxpayer identification number.
- 5Prepare Copies B and C for the employee and for records.
- 6Submit Form 3921 to the IRS by the filing deadline.
- 7Retain the original copy for corporate records as proof of filing.
Known limitations
- 1Form 3921 does not apply to employee stock purchase plans under section 423(c); those transfers use Form 3922.
- 2Individuals are not required to file Form 3921; filing is limited to corporations, related corporations, agents, and other parties described in the instructions.
- 3If a transfer falls under the unspecified exception noted in the instructions, Form 3921 is not required.
- 4Box 8 is only used when the exercise price per share is not fixed or determinable on the grant date; otherwise it must be left blank.
Field map
Compact field-by-field guide
General Info
2 items
Full legal name and taxpayer identification number (SSN or EIN).
Current mailing address.
Details
2 items
Complete all applicable sections of this form according to the official IRS instructions.
Enter the relevant dollar amount if this form involves tax calculation.
Certification
1 items
Read and acknowledge any certifications required by this form.
Signatures
1 items
Sign and date. Unsigned forms cannot be processed.
Almost done reviewing the fields?
Fillable formOpen in Editor->The form is revised 04/2025; the source points to the latest information page at IRS.gov/Form3921 and notes the e‑file threshold was lowered to 10 returns effective Jan 1 2024.
What changed or needs a fresh check
- Edition date — confirm the revision date reads 04/2025 on the form
- Fee — Not stated in the official source
- Mailing address — Not stated in the official source
- Signature — Not stated in the official source
- E‑file eligibility — verify total information returns do not exceed 10 for the calendar year
Quick Facts
Downloads
After you file
- 1Furnish a statement to the employee whose name appears on Form 3921 after filing.
- 2Optionally designate an account number for the filing as encouraged by the IRS.
- 3If an error is discovered, submit a corrected or voided Form 3921 as described in the general instructions.
- 4Retain a copy of the filed Form 3921 and any statements for your records.
Sources
- SRCInstructions p.1 — filing requirement: every corporation that transfers stock on an incentive stock option exercise must file Form 3921.
- SRCInstructions p.1 — exception noted: the text includes the word “Exception.” indicating some transfers are excluded.
- SRCInstructions p.1 — parties that may file: corporation, related corporation, agent, brokerage firm, and party controlling remuneration.
- SRCInstructions p.1 — statement to transferee required: filers must furnish a statement to the person named on Form 3921.
- SRCInstructions p.1 — account number encouragement: the IRS encourages designating an account number for all Forms 3921.
- SRCInstructions p.2 — box 8 rule: leave box 8 blank if the exercise price per share is fixed or determinable on the grant date.
- SRCInstructions p.1 — e‑file threshold: lowered to 10 returns effective January 1 2024 (Form 9972).
- SRCInstructions p.1 — fillable online PDFs: copies of Form 3921 are available as fillable PDFs at IRS.gov/Form3921.
- SRCInstructions p.1 — IRIS portal: IRS developed IRIS for e‑filing information returns.
- SRCInstructions p.1 — corrected and void returns: general reminders include “Corrected and void returns.”
Common confusion points
Do I need to file Form 3921 as an individual?
The filing requirement is limited to corporations and related parties.
→ Verify that the filer is a corporation, a related corporation, an agent, or another listed party.
Should I fill in box 8 when the exercise price is fixed on the grant date?
Box 8 is only for non‑fixed prices; the instructions say to leave it blank if the price is fixed.
→ Confirm the price is fixed or determinable on the grant date and leave box 8 empty.
Can I e‑file Form 3921 if I have fewer than 10 returns?
The e‑file threshold was lowered to 10 returns for the filing year.
→ Use paper filing when filing fewer than 10 Forms 3921.
Am I required to give the employee a copy of the filing?
The instructions require furnishing a statement to the transferee.
→ Provide the employee with the required statement after filing.
Is an account number mandatory on Form 3921?
The IRS only encourages the use of an account number, not mandates it.
→ Include an account number if you choose; otherwise it may be omitted.
Do I use Form 3921 for a stock purchase plan?
Form 3921 covers section 422(b) options, while stock purchase plans fall under section 423(c).
→ Use Form 3922 for employee stock purchase plan transfers.
Workflow map
Related forms and next steps
Before
Current
After
Often used with
⚠ If something goes wrong
- File a corrected or voided Form 3921 as outlined in the general instructions.
Questions about IRS Form 3921
What is IRS Form 3921 used for?
Form 3921 tells the IRS when a company gives an employee stock after they exercise an incentive stock option. The company reports the grant date, exercise date, and price per share. It also must give a copy of the form to the employee.
Who must file IRS Form 3921?
Every corporation that transfers a share of stock to a person when the person exercises an incentive stock option described in section 422(b) must file Form 3921 for each such transfer.
What information does IRS Form 3921 require?
The form collects the option’s grant date (Box 1), the exercise date (Box 2), and the exercise price per share (Box 3).
Where do I file IRS Form 3921?
The form can be filed electronically via the IRS Information Reporting Intake System (IRIS) at IRS.gov/IRIS or through the e‑file options listed at IRS.gov/InfoReturn.
How do I complete IRS Form 3921?
First, complete Boxes 1‑3 with the grant date, exercise date, and exercise price per share. Then, optionally assign an account number and furnish a copy of the completed Form 3921 to the employee. File the form electronically through IRIS or submit a paper copy to the IRS. Sign the form before sending.
What happens if IRS Form 3921 is filed incorrectly?
Failure to file can subject the corporation to penalties under the general information‑return rules.
Do I need to file Form 3921 as an individual?
The filing requirement is limited to corporations and related parties. Verify that the filer is a corporation, a related corporation, an agent, or another listed party.
Should I fill in box 8 when the exercise price is fixed on the grant date?
Box 8 is only for non‑fixed prices; the instructions say to leave it blank if the price is fixed. Confirm the price is fixed or determinable on the grant date and leave box 8 empty.
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