42-004: IA 1120S Income Tax Return for S Corporations 42-004 (2024)
Iowa · Iowa DOR · Used for tax years 2024
The 2024 IA 1120S is Iowa’s income tax return for S corporations. It reports corporation and shareholder information, federal income and deductions, Iowa adjustments, and Iowa-source distributive items.
Who files this form
The IA 1120S is Iowa’s income tax return for S corporations. This version is for calendar year 2024 or another fiscal year entered on the return.
The form does not spell out which S corporations are required to file.
What you'll need
- Federal return: Include a complete copy of your federal return, excluding federal K-1s. Part 4 uses amounts from federal Form 1120-S and Schedule K.
- Corporation and shareholder information: Have the corporation’s legal name, address, FEIN, NAICS code, shareholder counts, and pass-through representative details ready.
- Receipts and payment information: Schedule E asks for Iowa receipts and receipts everywhere. Schedule C asks for estimated tax payments, prior-period credits, voucher payments, and other payments.
Include these additional documents when they apply:
- IA 102 for an amended return.
- Schedule DE if reporting income from disregarded entities.
- Schedule D for nonbusiness income reported on Part 4, lines 22 or 26.
- Supporting schedules for remaining Iowa net operating loss or credit carryforwards from C corporation years.
- Schedule CC for composite and PTET credits.
- IA 103 if making the audit election to pay on behalf of shareholders.
- IA 2220 for the underpayment of estimated tax penalty on line 49.
- A statement for other payments reported on Schedule C.
How to file
You can e-file or mail the return. The form warns that you may be required to file electronically.
Mail returns to:
Corporation Tax Return Processing
Iowa Department of Revenue
PO Box 10468
Des Moines, IA 50306-0468
Include a complete copy of your federal return, excluding federal K-1s. Sign by hand or use a digital signature with a digital certificate. Stamped or typed signatures are not accepted.
Do not email your return. Forms and schedules are available at revenue.iowa.gov.
Common mistakes
- Leaving Schedule E blank: The form says the Business Activity Ratio schedule must be completed.
- Using a typed or stamped signature: Sign by hand or use a digital signature with a digital certificate.
- Omitting the federal return: A complete copy must accompany the Iowa return, excluding federal K-1s.
- Forgetting IA 102 with an amended return: The form requires this attachment.
- Completing Part 6 without a PTET election: Check the box and complete Part 6 only if the corporation has elected, or is electing, entity-level taxation for this tax year. The election is irrevocable.
- Assuming no tax due means no late filing penalty: The form warns that a late filing penalty may apply even if no tax is due.
- Emailing the return: The form specifically says not to email it.
Questions people ask
Can an overpayment be applied to the next return?
Yes. Line 52 lets you apply an overpayment to the next period’s return. Line 53 reports the remaining amount to be refunded.
Can the corporation elect to pay pass-through entity tax?
Part 6 provides a PTET election checkbox. Complete that part only if the corporation has elected, or is electing, to be taxed at the entity level under Iowa Code section 422.16C for this tax year. The election is irrevocable.
What if the corporation reports income from disregarded entities?
Answer the question in Part 3 and include Schedule DE with the return.
Can someone else discuss the return with the Department?
The form includes a Third Party Disclosure Designee section where you can indicate whether you want to allow an individual to discuss the return with the Department.
Where can I ask questions?
Call 515-281-3114 or 800-367-3388, or email idr@iowa.gov. Do not email your return.