Transferor and employee boxes
The transferor's name and address, the transferor's TIN, the employee's TIN, the employee's name and address, and an account number.
3921
Exercise Of an Incentive Stock Option Under Section 422(b)
- Agency
- IRS
- Revision
- Rev. April 2025
- Fillable fields
- 43
- Pages
- 4
- Official source
- IRS form page
- Checked
- October 21, 2026
Form 3921: Exercise of an Incentive Stock Option Under Section 422(b)
Form 3921, Exercise of an Incentive Stock Option Under Section 422(b), is an information return a corporation files with the IRS. The IRS page says corporations file it for each transfer of stock to any person pursuant to that person's exercise of an incentive stock option described in section 422(b). The instructions say every such corporation files one Form 3921 for each transfer made during the calendar year.
The form records the date the option was granted, the date it was exercised, the exercise price per share, the fair market value per share on the exercise date and the number of shares transferred. The corporation sends Copy A to the IRS, gives Copy B to the employee and keeps Copy C.
Copy B tells the employee to keep the form and use it to figure gain or loss when the stock is sold, and points to Pub. 525 and Form 6251. The same instructions cover Form 3922. You can fill out the PDF free in your browser on this page and download it without an account.
What's on Form 3921
Boxes 1 and 2
Date option granted and date option exercised.
Boxes 3 and 4
Exercise price per share, and fair market value per share on the exercise date.
Box 5
The number of shares transferred pursuant to the exercise of the option.
Box 6
The name, address and TIN of the corporation whose stock is being transferred, if other than the transferor.
The three copies
Copy A for the IRS, Copy B for the employee with the Instructions for Employee, and Copy C for the corporation, with VOID and CORRECTED boxes.
How to fill out Form 3921
- 1
Employee name, address and TIN
Enter the name, address and TIN of the person to whom the shares were transferred pursuant to the exercise of the option.
- 2
Account number
The instructions say it is required when one person has several accounts with more than one Form 3921, and the IRS encourages one on every form.
- 3
Boxes 1 and 2
Enter the date the option was granted and the date the option was exercised.
- 4
Boxes 3 and 4
Enter the exercise price per share of stock, then the fair market value (FMV) per share on the date the option was exercised.
- 5
Box 5
Enter the number of shares of stock transferred pursuant to the exercise of the option.
- 6
Box 6
Enter the name, address and TIN of the corporation whose stock is transferred only if it is not the entity shown in the transferor boxes in the upper left corner.
Why fill Form 3921 on indox
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- The official blank straight from the IRS, not a copy someone retyped
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Copies, e-filing and statements
One form per transfer
The instructions say a corporation files Form 3921 for each transfer made during the calendar year.
Statement to the employee
A filer of Form 3921 also furnishes a statement to the person named on the form. The instructions say Copies B and C have been made fillable online in a PDF format.
E-filing
The instructions say the e-file threshold was lowered to 10 returns, counted across all information returns, for returns required to be filed on or after January 1, 2024. IRIS is the IRS online portal for e-filing information returns.
Truncated TINs
The employee's TIN may be truncated on payee statements but not on documents filed with the IRS. The payer's TIN may not be truncated on any form.
Continuous use revision
The instructions say to use them for tax year 2025 and later years until a superseding revision is issued.
Due dates and penalties
The instructions point to the General Instructions for Certain Information Returns for when and where to file, corrections and penalties.
Related forms
Who files Form 3921?
The corporation that transferred the stock completes and files the form. The employee receives Copy B and does not file it with the IRS.
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Questions about Form 3921
Why did I receive a Form 3921?
Copy B says your employer or transfer agent transferred your employer's stock to you pursuant to your exercise of an incentive stock option (ISO).
What do I do with Form 3921?
Copy B says to keep the form and use it to figure the gain or loss for the year in which the stock is sold or otherwise disposed of, and points to Pub. 525.
Can exercising an ISO affect the alternative minimum tax?
Copy B says a portion of the fair market value of the stock may have to be included in alternative minimum taxable income, and points to Form 6251 and its instructions.
What is the difference between Form 3921 and Form 3922?
Form 3921 reports the exercise of an incentive stock option under section 422(b). Form 3922 reports a transfer of stock acquired through an employee stock purchase plan under section 423(c).
Who keeps Copy C?
Copy C says it should be retained by the corporation whose stock has been transferred under section 422(b).
Why does my form show only part of my SSN?
Copy B says the form may show only the last four digits of your SSN, ITIN or ATIN for your protection, but the employer has reported your complete TIN to the IRS.