Form4: Form4 (2025)
Wisconsin · Wisconsin DOR · Used for tax years 2025
Wisconsin Form 4 is the 2025 Non-Combined Corporation Franchise or Income Tax Return. It reports Wisconsin income or loss, tax, credits, and payments to calculate the amount due or refund.
Who files this form
Form 4 is Wisconsin’s Non-Combined Corporation Franchise or Income Tax Return for 2025.
Do not use this form if filing as a combined group.
When it's due
For tax year 2025, the form states that the return is generally due on the 15th day of the 4th month following the close of the taxable year. It refers filers to the instructions for details.
If you have an extension of time to file, check item F and enter the federal extended due date.
What you'll need
- A copy of your federal return is required, even if you had no Wisconsin activity. Form 4 uses federal Form 1120, line 28, and total assets from Form 1120.
- Have the corporation’s Wisconsin DFI number, federal employer ID number, business activity (NAICS) code, and state and year of incorporation available.
- As applicable, gather Schedule 4V for additions, Schedule 4W for subtractions, Form N, the apportionment schedule used, Schedule 4I for insurance companies, Form 4BL for loss carryforwards, Schedule CR for credits, and Form U for interest, penalties, and late fees.
- Include Schedule AR for an amended return. Attach an explanation for applicable items in section E, such as an amended return, first return, or listed short-period return.
- Submit Schedule DE if the corporation is the sole owner of any limited liability companies.
- Enclose federal Schedule UTP or Form 8886 if you filed them with the IRS.
- Item H applies if you have related entity expenses and are required to file Schedule RT with the return.
How to file
The form refers to electronic filing but does not provide electronic filing steps.
If you are not filing electronically, make your check payable to Wisconsin Department of Revenue and mail your return to:
Wisconsin Department of Revenue
PO Box 8908
Madison WI 53708-8908
Complete the paper form in black ink. Do not staple or bind it. Use a paper clip to attach a check or money order in the marked space.
Include a copy of your federal return and applicable attachments. Complete the officer’s signature, title, and date fields.
Common mistakes
- Using Form 4 for a combined group. The form specifically says not to do this.
- Leaving out the federal return. A copy is required even if there was no Wisconsin activity.
- Using commas, cents, or parentheses for negative numbers. Enter whole-dollar amounts without commas, and show negatives with a minus sign, such as
-1000. - Filling unused lines. The form says to leave a line blank if there is no entry.
- Stapling or binding the return, or using ink other than black.
- Entering a loss carryforward on line 14 that exceeds line 13.
- Entering a negative amount on line 20 when nonrefundable credits on line 19 exceed gross tax on line 18. The form says to enter zero instead.
Questions people ask
Do I need to include my federal return if I had no Wisconsin activity?
Yes. You must file a copy of your federal return with Form 4, even if there was no Wisconsin activity.
What must I include with an amended return?
Check the amended return box in section E, attach an explanation, and include Schedule AR.
What if the corporation is the sole owner of an LLC?
Answer yes to item 45 and submit Schedule DE with the return. Item 46 asks whether you included the income of the listed LLCs in this return.
Can I apply an overpayment to next year’s estimated tax?
Yes. On line 35, enter the amount of the line 34 overpayment you want credited to 2026 estimated tax. Subtract that amount from line 34 to calculate the refund on line 36.
Can I authorize someone else to discuss the return with the department?
Yes. Select yes in the Third Party Designee section and provide the designee’s name, PIN, and phone number.