You may file an amended return or refund claim if the change is attributed to you and affects your tax due. To calculate a refund amount:

1. Recompute the joint tax due for your original return.
2. Recompute you and your ex-spouse’s separate tax due by completing Married Filing Separately returns for each of you. You will not file these returns.
3. Determine you and your ex-spouse’s share of the joint tax due, since neither spouse can receive a refund exceeding their share. Based on the results from steps 1 and 2, calculate your share using the formula below:

​​​​​​​Divide your separate tax due by the total of you and your ex-spouse's separate taxes due. Then, multiply that number by joint tax due to get your share.

4. Subtract your share of the joint tax due from your own withholding or estimated tax payments to determine your refund amount. File the amended return as Married Filing Jointly so that your filing status matches your original return. 

Example

Mary and Bill filed a joint return with a Minnesota taxable income amount of $110,000. The next year, they get a divorce.

Mary later realizes she failed to claim a $10,000 deduction on their joint return. She files a refund claim showing her taxable income for that year is now only $25,000 ($35,000 - $10,000).

The joint income is now $100,000 in taxable income (after taking Mary’s deduction), with the recomputed tax due of $10,000.

Mary must file the amended return as Married Filing Jointly (the same filing status as the original return since it's past the original due date).

Note: Regardless of marital status, the refund will still be sent to both parties.

You may file a protective claim by amending your tax return if you anticipate a refund in the future. This situation applies if your refund depends on something that will not be resolved until the deadline for claiming a refund has passed. Examples include a pending lawsuit or an expected law change.

To file a protective claim in Minnesota, you must first amend your federal tax return. Then, complete and file Form M1X. When selecting your reason for amending, check the box titled “Claim due to a pending court case.” Include a copy of your amended federal return.

After the situation is resolved, review the amended return you submitted to us for your protective claim.

• If your amended return showed the correct changes, send us a copy of the IRS audit report, notice of adjustment, or refund check showing your federal claim was accepted. Mail to:

Minnesota Department of Revenue
Mail Station 4122
600 N. Robert St.
St. Paul, MN 55146-4122

• If your amended return did not show the correct changes, file a new Form M1X showing all changes relating to the claim.