M3X: Amended Partnership Return Claim for Refund (2025)

Minnesota · Minnesota DOR · Used for tax years 2025

Minnesota Form M3X is used to amend a previously filed 2025 Minnesota partnership return and claim a refund. It reports changes to taxes, withholding, credits, and payments and calculates the corrected amount due or refund.

Who files this form

Partnerships must use Form M3X to correct an original Minnesota partnership return. Use the 2025 version to amend a 2025 return. For another tax year, use that year's Form M3X.

You must also amend if the IRS changes or audits your return, you amend your federal return, or you file an administrative adjustment request (AAR) with the IRS.

The text also requires partnerships affected by the 2026 Minnesota tax bill to amend using Form M3X and update Schedules KPCNC, KPINC, KPC, and KPI for the changes.

Form M3X can also be used to claim a refund and report changes to your Minnesota tax liability.

What you'll need

Have these records and attachments ready:

  • The Form M3 instructions for 2025, plus the amounts from your original return and any later amended returns or audit adjustments.
  • A separate, detailed explanation of each change, including calculations.
  • Corrected schedules affected by your changes, including amended partner schedules as applicable.
  • A complete copy of your amended federal Form 1065, if any. For an IRS adjustment, attach your amended federal return or the IRS correction notice.
  • Applicable schedules requested by the form, such as Schedule PTE, Schedules KPI, Schedule M3BBA, Schedule ETP, and Schedule EPC.
  • Credit certificate numbers for any applicable film production, agricultural asset owner, state housing, or short line railroad infrastructure modernization credits.
  • Your bank routing and account numbers if you want direct deposit.

How to file

  1. File your original return before filing Form M3X.
  2. Enter the tax year's beginning and ending dates, partnership information, and reason for amending. For an IRS adjustment, check the appropriate box and enter the final determination date.
  3. For lines 1–16, enter previously reported or adjusted amounts in column A, changes in column B, and corrected amounts in column C. Show decreases in parentheses. Leave column B blank where nothing changed.
  4. Attach your explanations, calculations, and required schedules. If amending solely because of the 2026 Minnesota tax bill, write “Conformity” in red at the top of Form M3X and the amended Schedules KPI and KPC issued to partners.
  5. Have a partner or LLC member sign the return. A paid preparer must also sign and provide the required identifying and contact information.
  6. Mail the return to:

Minnesota Partnership Tax

Mail Station 1760

St. Paul, MN 55146-1760

Payment: Pay electronically by logging in to e-Services at www.revenue.state.mn.us. To pay by check, select Make a Payment, then Check, and use the Payment Voucher System to create a voucher. Electronic payment cannot use a foreign bank account. Additional tax and interest must be paid with the amended return.

Common mistakes

  • Using the wrong year's form. Use the Form M3X for the year being amended.
  • Leaving changes unexplained. Enter each changed amount and attach a detailed explanation and related schedules. Missing changed amounts will delay processing.
  • Forgetting signatures. The return must be signed by a partner or LLC member, and a paid preparer must also sign.
  • Stapling or taping attachments. Do not staple anything you submit or tape enclosures to the return.
  • Not rounding amounts. Round to the nearest dollar: amounts under 50 cents round down, and amounts of 50 cents or more round up.
  • Trying to change estimated payments or refunds credited to later years. These cannot be amended after the original return is filed.
  • Submitting Form AWC with an amended return. Form AWC can only be filed with the original return. Later submissions will be denied.
  • Including penalty or interest in line 17. Do not include penalty, interest, or underpayment-of-estimated-tax amounts on that line.

Questions people ask

Can the partnership get a refund of nonresident withholding or PTE tax?

Nonresident withholding refunds are limited to overpayments that were not deducted or withheld from the partnership. PTE tax overpayments are limited if a partner has claimed the PTE tax credit on their return. The conformity guidance says the partnership cannot claim a PTE tax refund if partners already claimed the credit on their personal returns.

Can I receive my refund by direct deposit?

Yes. Complete line 27 with your checking or savings account information. Use an account not associated with a foreign bank. The routing number must have nine digits. The account number may have up to 17 characters, including numbers and letters, without hyphens, spaces, or symbols. If the bank information is incorrect or not accepted, you will receive a paper check.

Can I apply the refund to estimated taxes?

No. A Form M3X refund cannot be applied to your estimated tax account. You also cannot use funds in your estimated tax account to pay the amount owed on line 21.

Does Form M3X show my full unpaid tax balance?

Not necessarily. Lines 21 and 25 reflect the tax and credit changes reported on Form M3X. If taxes remain unpaid on your original Form M3, Form M3X is not intended to show your corrected total balance due.

Official sources

All versions of M3X