# Form 3921

URL: https://pdf.net/pdf-forms/tax-forms/form-3921
Category: Tax Forms
Attributes: Official IRS form, Trusted by accountants

IRS Form 3921 is an information return used to report the exercise of an incentive stock option by an employee.

You can fill out our editable Form 3921 directly online. Once you’re done, download it to your device and submit it to the IRS.

## Versions

- 2025 — [download PDF](https://cdn.sanity.io/files/i16te7yp/production/70788bca7767aa1671a4fcc3fbfe49efc636456b.pdf)

## How to Fill Out Form 3921

1. Open IRS Form 3921 in our PDF editor.
2. Fill out Copies A, B, and C according to the Form 3921 instructions.
3. File Copy A with the IRS.
4. Furnish Copy B to the employee who exercised their incentive stock option.
5. Keep Copy C for the corporation’s records.

## Facts

### What Is Form 3921 Used For?

Form 3921 is used to report the exercise of an incentive stock option (ISO) by an employee. Essentially, a corporation must file this information return for each employee who exercised their right to buy company stock at a predetermined price.

Employees should note that the spread between the exercise price and the fair market value at the time of exercise may be subject to the Alternative Minimum Tax (AMT), making Form 3921 data important for AMT calculations even if the stock is not immediately sold.

### Who Should Use Form 3921?

Form 3921 is primarily used by corporations, as they are the ones who must furnish it to each eligible employee and file it with the IRS. However, employees also use it to figure their gains and losses on their tax returns in the year when they sell or otherwise dispose of the stock.

### When Is Form 3921 Due?

Form 3921 is due to the employees by January 31st and to the IRS by February 28th or March 31st if filed electronically. If any of these dates fall on a weekend or a federal holiday, the deadline is pushed to the next working day.

### What Happens If Form 3921 Is Not Submitted?

If Form 3921 isn’t submitted on time, you may face the following penalties:

- $60 per return if it’s up to 30 days late
- $130 per return if it’s more than 30 days late but filed by August 1st
- $340 per return if it’s filed after August 1st or not at all
- $680 per return for intentional disregard

In addition to this, you may be charged interest on penalties if they aren’t paid on time.

### How and Where Do I File Form 3921?

You should file Form 3921 with the IRS using the addresses provided on the official website or the online Information Returns Intake System (IRIS). If you’re filing ten or more information returns in one tax year, you must do so electronically.

## Related forms

- [1040 Form](https://pdf.net/pdf-forms/tax-forms/1040-form)
- [Schedule D (Form 1040)](https://pdf.net/pdf-forms/tax-forms/schedule-d-form-1040)
- [Form 1099](https://pdf.net/pdf-forms/tax-forms/1099-form)
- [W2 Form](https://pdf.net/pdf-forms/tax-forms/w2-form)
- [Form 1040-X](https://pdf.net/pdf-forms/tax-forms/form-1040-x)