VOIDPaper only: marks a form on a sheet that should be ignored. It is not a correction; a filed return is undone with a corrected return.How corrections workCORRECTEDChecked on a return that replaces one already filed. Which fields to repeat, and whether two returns are needed, depends on the error.Type 1 vs Type 2 correctionsTransferor's nameWhat goes hereOn Form 3921 the TRANSFEROR boxes hold the corporation that transferred the stock on exercise of the incentive stock option and files the form. The employee who received the shares goes in the EMPLOYEE'S name and TIN boxes.Watch forIf the stock transferred belongs to a different corporation, name that corporation in box 6.Which name goes firstBox 1: Date option grantedWhat goes hereThe date the incentive stock option was granted.Watch forThe form is filed for the calendar year of the transfer of stock on exercise, not the year of grant. File one Form 3921 for each transfer made during the year.Click to open the row in the box tableBox 2: Date option exercisedWhat goes hereThe date the option was exercised.Watch forFor a transfer in the year, Copy B goes to the employee by January 31 of the next year and Copy A to the IRS by February 28, or March 31 if you file electronically.Click to open the row in the box tableTransferor's TINWhat goes hereThe TIN of the transferor corporation filing the form.Watch forA filer's TIN may never be truncated. Only the employee's TIN may be truncated, and only on the employee's statement, never on the copy filed with the IRS.Match it before you fileBox 3: Exercise price per shareWhat goes hereThe exercise price per share of stock.Watch forEnter the price for one share, not the total the employee paid for all the shares in box 5.Click to open the row in the box tableBox 4: Fair market value per share on exercise dateWhat goes hereThe fair market value of one share of stock on the date the option was exercised.Watch forUse the value on the exercise date in box 2, not the grant date. The employee may need it because part of the value of ISO stock can count toward the alternative minimum tax.Click to open the row in the box tableBox 5: Number of shares transferredWhat goes hereThe number of shares of stock transferred on exercise of the option.Click to open the row in the box tableTransferor's street addressWhat goes hereThe street address of the transferor, the corporation filing the form. The employee's own address goes in the EMPLOYEE boxes.Box 6: If other than transferor, name, address and EIN of corporation whose stock is being transferredWhat goes hereThe name, address and TIN of the corporation whose stock was transferred on exercise of the option.Required whenThat corporation is not the entity shown in the TRANSFEROR boxes in the upper left corner. If it is the same entity, leave box 6 blank.Click to open the row in the box tableTransferor's city or townWhat goes hereThe city or town, state and ZIP code of the transferor, the corporation filing the form.Account numberWhat goes hereYour account number for the employee.Required whenYou have multiple accounts for a person for whom you file more than one Form 3921. The IRS encourages an account number on every Form 3921.Hover over a box for what goes in it; click to open its row in the table below. On a touch screen, tap the box to jump to the row.
Who must file Form 3921
Every corporation that in a calendar year transfers stock to any person on that person's exercise of an incentive stock option described in section 422(b) must file Form 3921 for each transfer and furnish a statement to the employee. The corporation whose stock is transferred files, whether or not it is the employer, and a transfer agent or other party may file as its agent. A separate form is filed for each exercise, even by the same employee on the same day.
No form is required for an exercise by a nonresident alien employee to whom the corporation is not required to furnish a Form W-2 for the relevant period.
Threshold: All amounts, every transfer of stock pursuant to an ISO exercise during the calendar year; a separate form for each exercise.
What is reported, box by box
| Box | What it reports | Notes |
|---|---|---|
| 1 | Date option granted | All exercises, no dollar threshold: file one form for each transfer of stock on exercise of an incentive stock option in the year. The date the option was granted. Not required for a nonresident alien employee to whom you were not required to give a W-2 for any year from grant through exercise. |
| 2 | Date option exercised | The date the option was exercised. Copy B goes to the employee by January 31 of the next year; Copy A goes to the IRS by February 28, or March 31 if you file electronically. |
| 3 | Exercise price per share | The exercise price for one share of stock, not the total paid for all the shares. |
| 4 | Fair market value per share on exercise date | The fair market value of one share on the exercise date, not the grant date. The employee may need it for the alternative minimum tax. |
| 5 | Number of shares transferred | The number of shares of stock transferred on exercise of the option. |
| 6 | If other than transferor, name, address and EIN of corporation whose stock is being transferred | Only when the stock belongs to a corporation other than the one in the TRANSFEROR boxes: that corporation's name, address and TIN. Otherwise leave it blank. |
Box titles follow the current revision of the form. The IRS reads the payer and recipient name, TIN, address, account number and the money boxes; the state boxes are for the state copy only.
Payments that are not reported on Form 3921
- Nonstatutory options (their spread is wages on Form W-2), and ESPP transfers (Form 3922).
- Exercises by nonresident aliens to whom no W-2 is required for the period from grant to exercise.
Due dates and extensions
| Copy | Due | For 2026 returns |
|---|---|---|
| To the IRS, paper | February 28 | Monday, March 1, 2027 (February 28 is a Sunday) |
| To the IRS, electronic | March 31 | Wednesday, March 31, 2027 |
| To the recipient | January 31 | Monday, February 1, 2027 (January 31 is a Sunday) |
An automatic 30-day extension is available on Form 8809, filed by the due date on paper or through IRIS; a second 30 days requires a hardship showing. Recipient statements can be extended 30 days on Form 15397, online or by fax only. 10 or more information returns of any type in aggregate must be e-filed (T.D. 9972); IRIS is the only IRS intake system from filing season 2027, FIRE having been retired. A payer who e-files the originals must e-file the corrections.
For 2026 forms filed in 2027: January 31 falls on a Sunday, so that deadline moves to Monday, February 1, 2027; February 28 also falls on a Sunday, so the paper deadline moves to Monday, March 1, 2027. March 31 (electronic) and March 15 are weekdays. February 28 does not become February 29 in a leap year. The compliance calendar has every date with the weekend shifts applied.
Withholding and TIN matching
There is no payment to withhold on: an ISO exercise is not wages and not a reportable payment, so backup withholding and the IRS TIN Matching program do not apply. The employee's name and SSN come from payroll, which is the most reliable source in the whole information-return system, and mismatches on 3921 are rare; they arise from equity-plan platforms that carry a legal name different from payroll's.
Name and TIN errors on this form
Every information return is matched by the IRS on the first four characters of the payee's name (the name control) against the TIN. A mismatch produces a CP2100 line the following autumn and, unless the solicitation record is in order, a 972CG penalty the year after: $340 per return for 2026 forms filed in 2027 that are late or wrong, $690 for intentional disregard, with annual maximums of $4,191,500 ($1,397,000 for small filers) under Rev. Proc. 2025-32. The errors that recur on Form 3921:
- Equity platform versus payroll. The plan administrator's participant record is the one on the 3921; reconcile it to the W-2 name and SSN once a year.
- Former employees. ISOs exercised after termination (within the three-month window) still get a 3921 under the former employee's SSN.
- Transfers to a trust or on death follow the option holder's own reporting; exercise by an estate is reported to the estate.
The name control calculator shows what the IRS will derive from a name line, and the CP2100 guide covers what to do when the notice arrives.
Recipient statements and substitutes
The recipient statement for Form 3921 need not be a copy of the official form: a substitute may be combined with other account statements or reports, provided every required item is numbered and titled as on the official form, the tax year, form number and form name appear together, the recipient instructions are included, and, for the forms Pub 1099 lists, a telephone number with direct access to someone who can answer questions is shown. Publication 1179 (Rev. Proc. 2026-18) has the specifications; logos, slogans and advertising are not permitted on the statement itself. Statements may be furnished electronically only to a recipient who has affirmatively consented in a way that shows they can access the format, after the disclosures in Pub 1099 part M, and must stay posted through October 15. Copy B may show a truncated TIN (xxx-xx-1234); the IRS copy never may. The consent rules for furnishing statements electronically are under review: Notice 2026-4 asked for comments (due May 23, 2026) on whether the broker rules, and then the rules for every other payee statement, should change.
Corrections and state copies
A wrong amount, code or checkbox is a Type 1 correction: one corrected return with the CORRECTED box checked. The wrong form type is a Type 2 correction: a zeroed-out copy of the original plus a new original, in that order. A wrong or missing payee TIN or name is also Type 2 on paper, but IRIS corrects it in one step on the original record (Publication 5717). Publication 1099 also says you are not required to file a correction for a missing or incorrect TIN if you meet the reasonable-cause standard, only to use the right TIN on the next return, although the IRS encourages the correction. Details and the paper error charts are on the 1099 corrections page.
Form 3921 is not in the Combined Federal/State Filing program, so any state that requires it must receive it directly. Requirements by state are on the state pages.
Questions people ask about Form 3921
Is the spread on an ISO reported on the W-2?
Not at exercise, if the holding periods are met; the 3921 gives the employee the AMT adjustment. A disqualifying disposition puts ordinary income on the W-2 in the year of sale.
One form per employee per year?
No; one form per exercise.
Is 3921 in the Combined Federal/State program?
No.
Other federal forms
1042-S · 1097-BTC · 1098 · 1098-C · 1098-E · 1098-F · 1098-Q · 1098-T · 1098-VLI · 1099-A · 1099-B · 1099-C · 1099-CAP · 1099-DIV · 1099-G · 1099-INT · 1099-K · 1099-LPS · 1099-LS · 1099-LTC · 1099-MISC · 1099-NEC · 1099-OID · 1099-PATR · 1099-Q · 1099-QA · 1099-R · 1099-S · 1099-SA · 1099-SB · 3922 · 5498 · 5498-ESA · 5498-QA · 5498-SA · 5498-TA · W-2G · 1099-DA · Comparison table
Sources: IRS Publication 1099 (2026), General Instructions for Certain Information Returns, which replaced the separate General Instructions starting with tax year 2026; Instructions for Forms 3921 and 3922 (Rev. April 2025); Pub 1099 (2026); IRC 6039IRC 6039Internal Revenue Code, Cornell LII, 422; Regulations 1.6039-1. Threshold amounts are indexed for inflation from calendar year 2027; check IRS.gov/InflationAdjustment for the current year.