Equity Forms › E-File Form 3921 Online for 2025 Tax Year
At a Glance
E-File Form 3921 with BoomTax
BoomTax is an IRS-authorized e-file provider for Form 3921. Our platform is designed for corporations, stock plan administrators, and third-party service providers who need to report Incentive Stock Option exercises.
Why E-File Form 3921?
- IRS requirement: Electronic filing is mandatory for 10 or more returns
- Faster processing: E-filed returns are processed more quickly
- Built-in validation: Catch errors before submission
- Instant confirmation: Receive acknowledgment from the IRS
What You Need to E-File
To e-file Form 3921 with BoomTax, you will need:
- Corporation information: Name, address, and EIN
- Employee information: Name, address, and SSN
- Option exercise data:
- Box 1: Date option was granted
- Box 2: Date option was exercised
- Box 3: Exercise price per share
- Box 4: Fair market value per share on exercise date
- Box 5: Number of shares transferred
For details, see our What is Form 3921 guide.
How BoomTax Works
Import Your Form 3921 Data
You can import your data as Excel, XML, or use files from popular payroll providers like QuickBooks, UKG, ADP, and many more.
Step-By-Step Wizard
We walk you through the process with no complicated jargon. You can also live chat with a real person as you work on your filing for hands-on help.
E-File & Mail Employee Copies
Once your data is loaded, you can e-file and distribute employee copies in minutes.
Bulk Filing for Stock Plan Administrators
Companies with many ISO exercises can upload data in bulk via Excel or CSV. BoomTax validates your data and transmits it securely to the IRS through the FIRE system.
Filing Deadlines
- Employee copy: January 31
- IRS filing (paper): February 28
- IRS filing (electronic): March 31
For details, see our Form 3921 due date guide.
Related Forms
- E-File Form 3922: ESPP stock transfers
External Resources
Frequently Asked Questions About E-Filing Form 3921
Yes, BoomTax supports filing both Form 3921 (ISO exercises) and Form 3922 (ESPP transfers) in the same submission through the FIRE system. This is convenient for companies that offer both types of equity compensation.
You can file a corrected Form 3921 through BoomTax. Submit a new form with the correct information marked as a correction. The IRS will match it to the original filing using the employee's SSN and exercise date. You should also provide a corrected copy to the employee.
File a separate Form 3921 for each exercise. If an employee exercised options on different dates, or exercised options from different grants on the same date, each exercise requires its own form. BoomTax handles bulk uploads so you can file multiple forms per employee efficiently.
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BoomTax and its affiliates do not provide tax, legal, or accounting advice. This material has been prepared for informational purposes only, and is not intended to provide, and should not be relied on for, tax, legal, or accounting advice. You should consult your own tax, legal, and accounting advisors prior to engaging in any transaction.