M15C: Additional Charge for Underpayment of Estimated Tax (2024)
Minnesota · Minnesota DOR · Used for tax years 2024
Minnesota Schedule M15C calculates a C corporation’s additional charge for underpayment of estimated tax for 2024. It compares required installments with payments made and calculates the total charge to report on Form M4.
Who files this form
C corporations must use Schedule M15C to determine the additional charge for underpayment of estimated tax.
For tax year 2024, you do not need to complete this schedule if:
- You are filing your first Minnesota tax return.
- Your 2024 tax on M15C, line 1, is less than $500. In this case, you owe no additional charge.
Line 1 is your 2024 Form M4, line 1, minus the credits reported on Form M4, lines 4, 5, and 6.
When it's due
For tax year 2024, estimated tax installments are due on the 15th day of the third, sixth, ninth, and 12th months of the taxable year.
For a short taxable year, installments are due on the 15th day of the third, sixth, ninth, and final months. No installment is required for a short taxable year of fewer than four months.
If a due date falls on a weekend or legal holiday, payments made electronically or postmarked on the next business day are considered timely.
For calculating the additional charge, line 14 uses the date the underpayment is paid or the 15th day of the third month following the tax year, whichever is earlier.
What you'll need
Have these forms and records available:
- 2024 Form M4, including line 1 and credits on lines 4, 5, and 6.
- 2023 Form M4, if applicable, including line 1 and credits on lines 4 and 5.
- The corporation or designated filer's name, FEIN, and Minnesota Tax ID.
- Estimated tax payment amounts and dates, including any 2023 overpayment credited to your 2024 estimated tax account.
If more than one payment was made for a required installment, attach a separate computation for each payment.
If you use an alternative installment method, complete Schedule A of federal Form 2220 with the Minnesota adjustments and attach the federal schedule to M15C.
How to file
Attach Schedule M15C to your Form M4. Add the additional charges from line 16, enter the total on M15C, line 17, and carry that amount to Form M4, line 15.
The supplied text does not provide a mailing address or instructions for electronically filing the schedule.
Common mistakes
- Not rounding amounts. You must round to the nearest whole dollar.
- Working across columns too soon. Complete lines 7 through 13 for one column before completing the next column. For the first column only, enter line 6 directly on line 10.
- Using prior-year tax when an exception applies. Use line 1 for the required annual payment if you did not file a 2023 return, your preceding-year return covered less than 12 months, or you had no 2023 tax liability. Large corporations must follow the special instructions.
- Leaving out a credited overpayment. Include any 2023 overpayment credited to your 2024 estimated tax account in the first column of line 6.
- Missing required attachments. Attach a separate computation for each payment when an installment has multiple payments. Attach the federal schedule if you use an alternative installment method.
Questions people ask
How is the required annual payment determined?
Generally, line 3 is the smaller of your 2024 tax on line 1 or your 2023 tax on line 2. Exceptions apply if you did not file a 2023 return, the preceding-year return covered less than 12 months, you had no 2023 tax liability, or you are a large corporation.
How much is each required installment?
Generally, each installment is 25 percent of line 3 unless you use an alternative method. For a short taxable year, divide line 3 by the number of installments due. Large corporations have special rules.
Can I use a different method if my income varied during the year?
Yes. The instructions allow the Adjusted Seasonal Installment Method and the Annualized Income Installment Method. Use Schedule A of federal Form 2220, make the specified Minnesota adjustments, and attach the federal schedule to M15C.
How are payments applied when an earlier installment is unpaid?
Estimated tax payments are applied to underpaid installments in the order the installments were due. A later payment may therefore go toward an earlier underpayment before covering the current installment.
What counts as a large corporation?
A corporation is considered large if its Minnesota taxable net income after apportionment was $1 million or more in any of the three tax years immediately preceding the current year. For a unitary business, this test uses the combined Minnesota taxable net income of its members.