42-008: IA 1120S Schedule K-1 42-008 (2025)
Iowa · Iowa DOR · Used for tax years 2025
The 2025 IA 1120S Schedule K-1 reports a shareholder’s share of an S corporation’s income, deductions, Iowa modifications, and Iowa tax credits. It shows federal or all-source amounts and amounts attributable to Iowa, along with composite tax paid on the shareholder’s behalf and
Who files this form
The S corporation must include completed Iowa Schedule K-1s, including additional attachments, for all shareholders with its IA 1120S return.
Shareholders may have an Iowa filing requirement even if they are not Iowa residents. The form states that the S corporation must file a composite return for its nonresident shareholders, except under certain circumstances, and should notify shareholders if it has done so.
A shareholder must file a return to claim composite, PTET, or other tax credits.
What you'll need
The form calls for the following information and supporting items:
- Corporation legal name, address, and federal employer identification number (FEIN).
- Shareholder name, address, taxpayer ID number, residency status, entity type, and ownership percentage.
- Shareholder’s share of Iowa receipts, receipts everywhere, and total nonbusiness income.
- The S corporation’s Business Activity Ratio (BAR) from IA 1120S, Schedule E, line 13.
- Federal/all-source amounts and amounts attributable to Iowa for the shareholder’s income, deductions, and modifications.
- Iowa composite tax paid on the shareholder’s behalf on the 2025 IA PTE-C and Iowa PTET credits reported to the shareholder.
- Current-year Iowa credit amounts, Iowa tax credit codes, and certificate numbers.
Include any additional K-1 attachments with the completed schedules submitted with the IA 1120S return.
How to file
Include completed Iowa Schedule K-1s for all shareholders, along with any additional attachments, with the IA 1120S return.
The form does not provide a mailing address or e-filing directions. It directs taxpayers to revenue.iowa.gov or to call 515-281-3114 or 800-367-3388 for filing information for individuals, corporations, and other entities.
Common mistakes
- Leaving out a shareholder’s K-1 or attachments. Completed Iowa Schedule K-1s, including additional attachments, for all shareholders must be included with the IA 1120S return.
- Assuming a nonresident has no Iowa filing requirement. The form warns that shareholders may have a filing requirement even if they are not Iowa residents.
- Trying to claim credits without filing a return. A return must be filed to claim composite, PTET, or other tax credits.
Questions people ask
Could I need to file an Iowa return if I am not an Iowa resident?
Yes. The form states that shareholders may have an Iowa filing requirement even if they are not residents.
Does the S corporation file a composite return for nonresident shareholders?
The form says the S corporation is required to do so, except under certain circumstances. It should notify shareholders if it has filed a composite return on their behalf.
Must I file a return to claim Iowa tax credits?
Yes. A return must be filed to claim composite, PTET, or other tax credits.
Where does the Business Activity Ratio come from?
Use the S corporation’s BAR from IA 1120S, Schedule E, line 13.
Where can I get more filing information?
The form directs taxpayers to revenue.iowa.gov or to call 515-281-3114 or 800-367-3388.