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IRSCredits & Incentives (8800/8900 Series)

Official form guide

Form 8879S: 8879-S

Form 8879-S is the IRS e-file Signature Authorization for Form 1120-S, the U.S. Income Tax Return for an S corporation. It authorizes an electronic return originator (ERO) to transmit the corporation's return electronically and to sign the return on behalf of the corporation. The form must be completed and provided to the ERO before the electronic transmission of Form 1120-S.

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Form Overview

IRS Form 8879S - 8879-S

Form 8879-S is the IRS e-file Signature Authorization for Form 1120-S, the U.S. Income Tax Return for an S corporation. It authorizes an electronic return originator (ERO) to transmit the corporation's return electronically and to sign the return on behalf of the corporation. The form must be completed and provided to the ERO before the electronic transmission of Form 1120-S.

The form captures the corporation’s name, EIN, address, tax year, type of return (Form 1120‑S), the ERO’s name and EFIN, the officer’s signature and date, and a taxpayer PIN if used.

Risk Radar

Scan points
  • 1A missing or mismatched EIN will cause the electronic return to be rejected by the IRS.
  • 2Missing officer signature
  • 3Incorrect EIN or corporation name
  • 4Using an outdated edition date
  • 5Entering the wrong tax year or return type

Plain English

When an S corporation files its tax return online through a tax‑preparer or service that is an authorized ERO, the corporation signs Form 8879‑S to give that preparer permission to send the return to the IRS and to act as the corporation’s electronic signature. The corporation keeps a copy of the signed form; the ERO retains it for their records. No copy of Form 8879‑S is sent to the IRS unless the agency specifically requests it.

Submission Date

  • Filing date: 2022-01-03 22:11:14
  • Preparation window: collect IDs, supporting records, and signatures in advance.
  • Final review: verify names, dates, and required fields before submission.

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Glossary Terms

income taxincome

Hover a term to preview the meaning.

What this form is for

  • Use when filing Form 1120‑S electronically through an authorized ERO
  • Do not use for paper filing of Form 1120‑S
  • Do not use for other entity types such as Form 1120 (C corporation) or Form 1065 (partnership)

Form selector

Use this form or another form?

Filing Form 1120 (C corporation) electronically

Authorizes e‑signature for corporate return

✓ Verify you have the correct form for entity type

Form 8879

Filing Form 1065 partnership return electronically

Partnership e‑signature authorization

✓ Confirm you need the partnership version

Form 8879‑P

Filing Form 1120‑S paper return

Electronic signature not required

✓ Ensure you are not using 8879‑S for a paper return

No form needed

Amending a previously filed 1120‑S electronically

Same authorization needed for amended e‑file

✓ Check if the amendment is being e‑filed

Form 8879‑S (new authorization)

Using a preparer who is not an authorized ERO

Only EROs may use 8879‑S

✓ Confirm the preparer’s EFIN is active

Not applicable

Deadline or filing window

Form 8879‑S must be completed and provided to the ERO before the electronic transmission of Form 1120‑S, which must meet the corporation’s filing deadline. For most calendar‑year S corporations the original deadline is March 15, with an automatic six‑month extension to September 15 if Form 7004 is filed. Fiscal‑year S corporations must file by the 15th day of the third month after the close of their tax year.

Checklist

What you need before filling it out

1

Corporation name

Articles of incorporation or IRS CP 575 · Corporate records

⚠ Misspelling or using a DBA incorrectly✕ Medium
2

EIN

IRS notice CP 575 or prior year return · Prior year return

⚠ Using a wrong EIN✕ High
3

Tax year

Prior year return or internal calendar · Internal records

⚠ Entering the wrong year✕ Medium
4

Officer signature

Corporate resolution or officer ID · Corporate records

⚠ Missing or unauthorized signature✕ High
5

ERO EFIN

ERO’s IRS acceptance letter · ERO records

⚠ Entering an incorrect EFIN✕ Medium
6

Taxpayer PIN

Prior year PIN or self‑selected PIN · Taxpayer records

⚠ Forgetting to enter a PIN when required✕ Low
7

Date

Today’s date · Calendar

⚠ Entering a future or past date✕ Low

Before you submit

  1. 1Verify you have the latest edition of Form 8879‑S
  2. 2Confirm the corporation’s legal name matches IRS records
  3. 3Double‑check the EIN is correct
  4. 4Ensure the tax year and form type (1120‑S) are correctly selected
  5. 5Confirm the ERO’s name and EFIN are accurate
  6. 6Make sure an authorized officer has signed and dated the form
  7. 7If a taxpayer PIN is used, verify it is entered correctly
  8. 8Check that no required fields are left blank
  9. 9Ensure the form is not being sent to the IRS unless specifically requested
  10. 10Retain a copy of the signed form for your records
  11. 11Confirm the ERO will retain the form for at least three years
  12. 12Verify that the form is attached to the electronic return before transmission

How to file this form

  1. 1Download the current Form 8879‑S from IRS.gov
  2. 2Enter the corporation’s full legal name, EIN, and mailing address
  3. 3Select the tax year and indicate that the return is Form 1120‑S
  4. 4Enter the ERO’s name and EFIN
  5. 5Have an authorized officer sign and date the form (add PIN if applicable)
  6. 6Give the completed, signed form to the ERO before they transmit the return
  7. 7Keep a copy of the signed form for at least three years
  8. 8Monitor for the IRS acceptance notice or any rejection notice

Known limitations

  1. 1Only authorizes electronic signing of Form 1120‑S; cannot be used for other returns
  2. 2Not valid for paper‑filed Form 1120‑S
  3. 3Must be retained by the ERO, not submitted to the IRS unless requested
  4. 4Does not replace Form 8453‑S for certain situations that require a paper signature
  5. 5Valid only for the tax year indicated on the form
  6. 6If the corporation changes its EIN, a new Form 8879‑S must be completed

Field map

Compact field-by-field guide

6 fields

Entity Info

1 items

Taxpayer Name and TIN

Name and taxpayer ID of the entity claiming the credit.

Requiredtext

Credit Info

1 items

Credit Type

Type of credit or incentive being claimed.

Requiredselect

Calculation

2 items

Qualifying Amount

The base amount used to calculate the credit.

Requiredamount
Credit Amount

Calculated credit amount after applying formulas and limitations.

Requiredamount

Certification

1 items

Supporting Information

Detailed breakdown supporting the credit calculation.

text

Signatures

1 items

Signature

Sign and date the form.

Requiredsignature
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Current form status
IRS

The most recent version of Form 8879‑S is revised for the 2024 tax year; always verify the edition date on the IRS website before use.

What changed or needs a fresh check

  • Edition date – check the bottom left corner for the current year’s version
  • Fee – there is no fee to file or obtain Form 8879‑S
  • Mailing address – not applicable; the ERO retains the form, do not mail to the IRS
  • Signature requirement – an authorized officer must sign and date the form
  • PIN field – optional taxpayer PIN may be entered if used by the ERO
  • Retention period – ERO must keep the signed form for at least three years

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Quick Facts

An officer of the S corporation (such as the president, vice‑president, treasurer, or other authorized person) completes and signs Form 8879‑S. The form is filed by the corporation, not by the ERO.
The form captures the corporation’s name, EIN, address, tax year, type of return (Form 1120‑S), the ERO’s name and EFIN, the officer’s signature and date, and a taxpayer PIN if used.
Form 8879‑S must be completed and given to the ERO before the electronic transmission of Form 1120‑S, which must meet the corporation’s filing deadline (generally March 15 for calendar‑year S corps, with extensions to September 15 if Form 7004 is filed).
The completed form is given to the ERO, who keeps it in their records; it is not mailed to the IRS unless the IRS requests it. The ERO must retain the signed form for at least three years.
If the form is missing, contains incorrect information, or is not properly signed, the IRS may reject the electronic return, delay processing, or assess penalties for an unauthorized filing.
1) Obtain the current version of Form 8879‑S from the IRS website. 2) Fill in the corporation’s legal name, EIN, address, and tax year. 3) Indicate that the return is Form 1120‑S and enter the ERO’s name and EFIN. 4) Have an authorized officer sign and date the form (and enter a taxpayer PIN if applicable). 5) Provide the signed form to the ERO before they transmit the return. 6) Keep a copy of the signed form for your records.

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After you file

  1. 1Keep the signed copy of Form 8879‑S in your corporate records
  2. 2Retain the ERO’s acknowledgment or transmission confirmation
  3. 3Monitor for the IRS acceptance notice or any rejection notice
  4. 4Track any extension filings (Form 7004) and ensure they are linked to the original return
  5. 5Maintain the form for at least three years from the date of transmission
  6. 6If filing an amended return electronically, complete a new Form 8879‑S for the amendment
  7. 7Document any correspondence with the ERO regarding the return
  8. 8Verify that any subsequent returns use a fresh authorization if required

Sources

  • SRCForm 8879‑S is the IRS e‑file Signature Authorization for Form 1120‑S (U.S. Income Tax Return for an S corporation).
  • SRCThe form must be signed by an officer of the corporation who is authorized to sign the tax return.
  • SRCIt is filed after the corporation’s Form 1120‑S has been prepared and before the return is transmitted electronically to the IRS.
  • SRCForm 8879‑S is submitted to the IRS together with the electronic filing of Form 1120‑S; it is not mailed separately.
  • SRCThe form includes a declaration that the information on the return is true, correct, and complete to the best of the signer’s knowledge.
  • SRCA PDF copy of the signed Form 8879‑S must be retained by the corporation for its records.
  • SRCThe form does not require a filing fee.
  • SRCThe deadline for submitting Form 8879‑S is the same as the deadline for the electronic filing of Form 1120‑S, typically March 15 (or the next business day if the 15th falls on a weekend or holiday).
  • SRCIf the corporation obtains an extension for filing Form 1120‑S, the extension applies to Form 8879‑S as well.
  • SRCNot clearly stated in the provided official source

Common confusion points

Using Form 8879‑S for Form 1120

Mistaken belief that one form fits all corporations

→ Check the entity type before selecting the form

Sending the form to the IRS

Thinking it must be filed with the return

→ Remember the ERO retains it unless the IRS requests it

Confusing taxpayer PIN with EFIN

Both are numbers but serve different purposes

→ Verify the PIN is officer‑selected, the EFIN belongs to the ERO

Thinking the form expires after transmission

Belief that authorization is one‑time only

→ Retain the signed form for three years as required

Assuming no signature needed if using PIN

Overreliance on the PIN

→ An officer signature is still required even when a PIN is used

Using an outdated edition date

Not checking the IRS website

→ Verify the edition date matches the current year’s version

Believing the form can be used for amended returns without a new signature

Assuming amendment inherits original authorization

→ Each electronic amendment requires a new Form 8879‑S

Workflow map

Related forms and next steps

4 signals

Before

Prepare Form 1120‑S for the tax year

Current

8879S

After

ERO transmits the electronic return to the IRS

Often used with

Form 8879‑S

⚠ If something goes wrong

  • IRS rejection notice → verify Form 8879‑S details and resubmit

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Source transparency

Copyright & Licensing - US Government Forms

Independent guide

BrieflyGo links to and explains official public form sources. We are not a government agency, and this page is for general form guidance, not legal advice.

Public DomainCreated by the U.S. federal government. Not subject to copyright (17 USC § 105). Freely copyable without restriction.
Public DomainCreated by the U.S. federal government. Not subject to copyright (17 USC § 105). Freely copyable without restriction.
Public DomainCreated by the U.S. federal government. Not subject to copyright (17 USC § 105). Freely copyable without restriction.
Public DomainCreated by the U.S. federal government. Not subject to copyright (17 USC § 105). Freely copyable without restriction.
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