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Official form guide
Form 8879C: 8879-C
IRS Form 8879-C is the IRS e‑file Signature Authorization for corporate income tax returns. It is used when a corporation files Form 1120, 1120‑S, 1120‑F, or a related corporate return electronically and needs to provide a signed declaration that the return is true, correct, and complete.
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IRS Form 8879C - 8879-C
IRS Form 8879-C is the IRS e‑file Signature Authorization for corporate income tax returns. It is used when a corporation files Form 1120, 1120‑S, 1120‑F, or a related corporate return electronically and needs to provide a signed declaration that the return is true, correct, and complete.
Risk Radar
Scan points- 1A single missing signature can cause the entire corporate return to be rejected.
- 2Missing or unsigned Form 8879‑C
- 3Signature does not match IRS records for the officer
- 4Incorrect EIN or tax year entered
- 5Using the wrong edition of the form
Plain English
When a business files its corporate tax return online, the IRS still requires a paper signature to confirm the return is accurate. Form 8879‑C is that signed paper, attached to the electronic filing. It lets the corporation sign once and keep the rest of the filing digital.
Submission Date
- Filing date: 2021-11-16 22:14:01
- Preparation window: collect IDs, supporting records, and signatures in advance.
- Final review: verify names, dates, and required fields before submission.
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What this form is for
- Use when filing an electronic corporate income tax return (Forms 1120, 1120‑S, 1120‑F).
- Do not use for individual returns; those require Form 8879.
- If filing a paper return, no Form 8879‑C is needed.
Form selector
Use this form or another form?
Amended corporate return
Requires a separate signature page
✓ Verify amendment instructions
Partnership return
Different signature authority rules
✓ Use only for partnerships
Non‑profit return
No 8879‑C required
✓ Check Form 990‑EZ filing guide
Deadline or filing window
The signed Form 8879‑C must be received by the IRS before the electronic filing deadline for the corporate return, usually the 15th day of the fourth month after the corporation’s year‑end. If the deadline is missed, the return will be rejected and must be re‑submitted.
- —Tax year | Return year entered on Form 1120 | Tax year field on 8879‑C | Verify year matches return
Checklist
What you need before filling it out
Corporation name
Articles of Incorporation or EIN verification · Return header
EIN
IRS notice or prior return · Top of form
Authorized officer title
Corporate bylaws or board minutes · Signature block
Signature
Hand‑signed on paper · Signature line
Tax year
Return worksheet · Tax year box
Before you submit
- 1Confirm form edition is 2024
- 2Match EIN and corporation name with the electronic return
- 3Verify tax year on the form matches the return
- 4Ensure the correct authorized officer signed
- 5Check that the signature is legible and dated
- 6Attach the form to the correct cover sheet or fax cover
- 7Mail or fax to the address specified in the e‑file instructions
- 8Retain a copy for corporate records
- 9Record the mailing/fax date for deadline tracking
- 10Confirm receipt with the IRS if possible
How to file this form
- 1Complete the corporate return in approved e‑file software.
- 2Print the generated Form 8879‑C.
- 3Have the authorized officer sign and date the form.
- 4Attach the signed form to the e‑file cover sheet or fax cover.
- 5Mail or fax the package to the IRS processing center indicated.
- 6Keep a scanned copy of the signed form for the corporation’s files.
- 7Track mailing/fax confirmation to ensure timely receipt.
Known limitations
- 1Form does not include a fee schedule; fees are handled by the e‑file provider.
- 2Signature verification is manual; the IRS cannot validate electronic signatures on this form.
- 3The form does not provide a field for electronic signatures; a handwritten signature is required.
- 4If the corporation has multiple authorized officers, only one signature is required on this form.
Field map
Compact field-by-field guide
Entity Info
1 items
Name and taxpayer ID of the entity claiming the credit.
Credit Info
1 items
Type of credit or incentive being claimed.
Calculation
2 items
The base amount used to calculate the credit.
Calculated credit amount after applying formulas and limitations.
Certification
1 items
Detailed breakdown supporting the credit calculation.
Signatures
1 items
Sign and date the form.
Almost done reviewing the fields?
Fillable formOpen in Editor->Form 8879‑C is currently in its 2024 edition. Verify the IRS website for any updates before filing.
What changed or needs a fresh check
- Edition date – confirm 2024 edition on the IRS website
- Fee – no filing fee for Form 8879‑C itself
- Mailing address – use the address listed in the e‑file software instructions
- Signature line – ensure officer’s name matches IRS records
- Tax year box – match the year on the corporate return
Quick Facts
Downloads
After you file
- 1Store the signed Form 8879‑C with the corporate tax file for at least three years.
- 2Record the filing date and IRS acknowledgment number.
- 3Monitor IRS correspondence for acceptance or rejection notices.
- 4If rejected, correct the issue (e.g., missing signature) and resubmit promptly.
- 5Update corporate records to reflect the filing date.
- 6Notify the tax preparer of any issues that arise.
Sources
- SRCForm 8879‑C title and purposeIRS official form description
- SRCAuthorized officer signature requirementIRS instructions for 8879‑C
- SRCTax year and EIN fieldslayout of the form
- SRCEdition date 2024IRS form revision history
- SRCMailing address guidanceIRS e‑file submission instructions
- SRCDeadline alignment with corporate return due dateIRS filing calendar
- SRCNo filing fee for 8879‑CIRS fee schedule
- SRCSignature must be handwrittenIRS signature requirements
- SRCNot clearly stated in the provided official source
Common confusion points
Form 8879‑C vs. Form 8879 – corporate vs. individual returns
Use the C version only for corporations
→ Verify return type first
Signature line location – some software places it on a separate page
Ensure the printed form includes the signature block
→ Check the PDF preview before printing
Tax year box – often pre‑filled incorrectly by software
Compare with the return’s tax year
→ Double‑check the year field
Mailing address – different IRS centers for different return types
Use the address listed in the e‑file software guide
→ Confirm before sending
Authorized officer title – some officers have multiple titles
Use the title that appears on the corporate records
→ Match title exactly
Electronic vs. fax submission – not all e‑file systems support fax
Verify your software’s submission method
→ Choose the method indicated in the instructions
Edition date
:
Using a prior year’s form can cause rejection
Verify the 2024 edition on the IRS site
Signature legibility
Workflow map
Related forms and next steps
Before
Current
After
Often used with
⚠ If something goes wrong
- Form 12171 (Request for Penalty Relief) for rejected e‑file
Source transparency
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