M4X: Amended Corporation Franchise Tax Return (2024)

Minnesota · Minnesota DOR · Used for tax years 2024

Form M4X is Minnesota’s 2024 Amended Corporation Franchise Tax Return. It reports previously reported amounts, net changes and corrected amounts for income, deductions, taxes, credits and payments to determine the amount due or refund.

Who files this form

Use the 2024 Form M4X to claim a refund or report changes to a corporation’s Minnesota franchise tax liability for tax year 2024. File it only after filing the original return.

If you amend your federal return or the IRS adjusts it, you must notify the Minnesota Department of Revenue within 180 days. Attach a copy of the amended federal return or adjustment notice to Form M4X.

When it's due

For tax year 2024, the instructions give these filing time limits:

  • File Form M4X within 3½ years after the return was due or within one year from the date of an order assessing tax, whichever is later.
  • If you filed the original return under an extension by the extended due date, you have up to 3½ years from that extended due date to amend.
  • Report federal return amendments or IRS adjustments within 180 days.

Any additional tax owed is due when you file the amended return. A penalty will be assessed if the additional tax and interest are not paid with it.

What you'll need

Have these records and attachments ready, as applicable:

  • Your original 2024 Minnesota return and any later amended returns or audit adjustments, to establish the previously reported amounts.
  • Your federal Form 1120 for the amended income calculation.
  • A copy of your amended federal return or IRS adjustment notice if reporting federal changes.
  • A detailed explanation of each change, including computations and supporting schedules, statements, or forms.
  • Corrected schedules if changing lines 7, 8, 20, 21, 22, 23, 24, 25, 30, 31, or 32.
  • Documentation showing Minnesota backup withholding claimed on line 33, such as Form 1099, Schedule KPI, Schedule KS, or the other documents listed in the instructions.
  • Form TPD if reporting a Tax Position Disclosure.
  • Applicable credit certificate or project numbers requested on the form.

You will also need the corporation’s FEIN, Minnesota Tax ID, tax-year dates, and original filing date. For a refund, provide routing and account numbers for an account not associated with any foreign banks.

How to file

  1. Enter the corporation’s identifying information, tax-year beginning and ending dates, and reason for amending.
  2. Enter previously reported or adjusted amounts in column A, changes in column B, and corrected amounts in column C. Show decreases in parentheses. If an amount has not changed, carry column A into column C.
  3. Complete the amended income calculation and explain each change in detail on page 3. Attach supporting documents.
  4. Have a person authorized by the corporation sign the return. A paid preparer must also sign and enter their PTIN and phone number.

Mail the return to:

Minnesota Department of Revenue

Mail Station 1255

600 N. Robert St.

St. Paul, MN 55146-1255

For payment options, go to www.revenue.state.mn.us and select Make a Payment. The instructions list bank-account payments, credit or debit cards, ACH credit, Fed Wire, and check or money order. Card payments carry a vendor fee.

If paying by check or money order with a paper return, create a voucher through the Payment Voucher System. Send the voucher and payment separately from the return. Electronic payment is required if you meet the requirements described in the instructions.

Common mistakes

  • Forgetting signatures: An authorized person must sign. A paid preparer must also sign and provide their PTIN and direct phone number.
  • Not rounding: Round to whole dollars. Drop amounts below 50 cents and round amounts of 50 cents or more up to the next dollar.
  • Stapling or taping attachments: Do not staple anything submitted or tape enclosures to the return.
  • Leaving out explanations or supporting records: Explain changes in detail. Without documentation of backup withholding, the department will disallow it and assess tax or reduce the refund.
  • Trying to change amounts credited to later years: Estimated payments and refunds credited to subsequent years cannot be amended.
  • Missing the federal-change reporting deadline: Failing to report within 180 days results in a penalty of 10% of additional tax due.
  • Paying by check when electronic payment is required: A 5% penalty applies to payments not made electronically, even if the check is timely.

Questions people ask

Can I apply my M4X refund to estimated tax?

No. This refund cannot be applied to your estimated tax account. Provide banking information for direct deposit into an account not associated with any foreign banks.

Does M4X show my full corrected balance if I still owe tax on the original return?

No. If the original Form M4 has unpaid taxes, Form M4X is not intended to show the corrected balance due. Lines 40 and 45 reflect changes to tax and credits reported on the amended return.

What if my 2024 federal amendment is solely due to H.R. 1?

If you amended solely because of the 2025 Federal Tax Budget and Reconciliation Bill (H.R. 1), the instructions say the Minnesota nonconformity adjustment will offset the federal taxable income changes. Write “H.R. 1” in red at the top of the amended return and see the Schedule M4NC instructions.

Does authorizing my preparer to discuss the return let them sign for the corporation?

No. Checking the authorization box does not let the preparer sign tax documents on your behalf or represent you at an audit or appeals conference. Those authorities require Form REV184b, Business Power of Attorney.

Official sources

All versions of M4X