MO-1120S: S Corporation Income Tax Return (2024)
Missouri · Missouri DOR · Used for tax years 2024
Form MO-1120S is Missouri’s S Corporation Income Tax Return for 2024. It reports Missouri additions and subtractions, the resulting S corporation adjustment, and each shareholder’s allocated share of that adjustment.
Who files this form
Form MO-1120S is Missouri’s S Corporation Income Tax Return for tax year 2024. The provided form does not state a general filing requirement, but it gives these completion rules:
- If the S corporation has Missouri modifications, complete Lines 1–15 and the shareholder information on page 3.
- If it has nonresident shareholders, complete Lines 1–15, the shareholder information on page 3, and Form MO-NRS.
- If it has income from sources outside Missouri, complete and attach Form MO-MSS.
What you'll need
Have the following information and applicable forms ready:
- Corporation name, address, charter number, Missouri tax identification number, federal employer identification number, and tax year beginning and ending dates.
- Federal Form 1120S information for state and local income taxes deducted, plus the amounts needed for the Missouri additions and subtractions.
- Each shareholder’s name, Social Security number, nonresident status, and share percentage from federal Schedule K-1.
- Form MO-NRS if the corporation has nonresident shareholders.
- Form MO-MSS if the corporation has income from sources outside Missouri. Complete and attach it.
- A copy of approved federal Form 7004 if claiming an approved federal extension. Select the extension box and attach the copy.
Use an attachment if needed to list all shareholders.
How to file
Complete the applicable return lines, shareholder information, and required attachments. The signature block calls for the officer’s signature, printed name, telephone number, and date signed, along with the applicable preparer information.
Mail the return to:
Missouri Department of Revenue
P.O. Box 336
Jefferson City, MO 65105-0336
For questions, the form lists (573) 751-4541 and corporate@dor.mo.gov.
Common mistakes
- Not selecting the address change box. The form warns that mailings may go to the last address on file if you do not select it.
- Leaving shareholders off page 3. All shareholders must be listed. Use an attachment if necessary.
- Not rounding shareholder percentages. Enter percentages from federal Schedule K-1 and round them to whole numbers.
- Not identifying the adjustment type. At the top of Column 5, indicate whether the adjustments are additions or subtractions.
- Overlooking missing paid-preparer information. If you answer Yes to the question about a paid preparer failing to sign or provide an IRS preparer tax identification number, enter the preparer’s name, address, and phone number in the applicable signature-block sections.
Questions people ask
What if the corporation has nonresident shareholders?
Complete Lines 1–15 on pages 1 and 2, the shareholder information on page 3, and Form MO-NRS.
What if the corporation has income from outside Missouri?
Complete and attach Form MO-MSS.
How do I show an approved federal extension?
Select the approved federal extension box and attach a copy of the approved Federal Extension, Form 7004.
How are Missouri adjustments allocated to shareholders?
Enter the adjustment from Line 13 or 14 as the total in Column 5. Multiply each shareholder’s percentage in Column 4 by that total. Each shareholder must report their Column 5 amount on Form MO-1040 as an addition to or subtraction from federal adjusted gross income.