Equity Forms › Form 3921 Due Dates and Filing Deadlines for 2026
At a Glance
Form 3921 Filing Deadlines
Form 3921 follows standard information return deadlines. Corporations must file for each Incentive Stock Option exercise during the tax year.
Key Deadlines
| Requirement | Deadline |
|---|---|
| Provide Copy B to employee | January 31 |
| File with IRS (paper) | February 28 |
| File with IRS (electronic) | March 31 |
If any deadline falls on a weekend or federal holiday, the deadline moves to the next business day.
Why Timely Filing Matters
Employees need Form 3921 to properly report their ISO exercises and calculate any Alternative Minimum Tax (AMT) liability. Late filing can cause problems for employees preparing their tax returns.
E-File Form 3921 with BoomTax
E-file your Form 3921 with BoomTax to ensure timely filing and avoid penalties.
External Resources
Frequently Asked Questions About Form 3921 Deadlines
Employees need Form 3921 early because they must use the information to calculate potential Alternative Minimum Tax (AMT) on Form 6251. The spread between exercise price and FMV is an AMT preference item, and employees need these figures to complete their tax returns.
Yes, you can request an automatic 30-day extension using Form 8809. The request must be filed before the original due date. Note that an extension to file with the IRS does not extend the January 31 deadline to provide statements to employees.
Penalties vary based on when you file. Reduced penalties apply if filed within 30 days of the deadline. Penalties increase progressively for later filings. Maximum penalties apply for forms filed after August 1 or not filed at all. Small businesses may qualify for reduced penalty rates.
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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.