Wisconsin: corporate income tax, a franchise (privilege) tax and an annual report due in your anniversary month.
Each fact below cites the agency page we read and the day we read it. Where a rule is still being confirmed, the page says so instead of showing a zero.
Verified facts
Corporate income tax
Yes
7.9%
Franchise or privilege
Yes
The franchise tax applies to all domestic corporations and to foreign corporations doing business in Wisconsin (or buying/selling Wisconsin lottery prizes), except where exempt by statute or barred by federal law. The rate is 7.9% and federal obligations are included in income under the franchise…
Entity annual report
Yes
annual · Domestic entities: deliver the annual report in the calendar-year quarter in which the anniversary date of registration occurs (Q1 March 31, Q2 June 30, Q3 September 30, Q4 December 31). Foreign entities registered to transact business: during the first calendar quarter (March 31).
Return due date
Published rule
Form 4 and Form 6 are due the 15th day of the 4th month after the end of the taxable year.
Extension
Not verified
Not verifiedZero activity / minimum tax
Not verified
Not verified
Long-form guide in professional review
Dates, extensions and payments
Filing and payment dates stay separate wherever the source supports it.
- Filing
Return filing
Form 4 and Form 6 are due the 15th day of the 4th month after the end of the taxable year.
Explicit exception: a fiscal year ending on June 30 is due the 15th day of the 3rd month after the end of the fiscal taxable year. Form 5S (tax-option S corporations) is due the 15th day of the 3rd…
- Entity report
Entity report
annualDomestic entities: deliver the annual report in the calendar-year quarter in which the anniversary date of registration occurs (Q1 March 31, Q2 June 30, Q3 September 30, Q4 December 31). Foreign entities registered to transact business: during the first calendar quarter (March 31).
Email me the Wisconsin guide
We send you this page with its sources, and we tell you if a date changes.
Frequently asked questions
Does Wisconsin impose a corporate income tax?
Yes. 7.9% Form: Form 4 (non-combined) / Form 6 (combined), Wisconsin Corporation Franchise or Income Tax Return.
Does Wisconsin charge a franchise or privilege tax?
Yes. Check the fact chip and the linked official source before budgeting for it.
When is the Wisconsin corporate return due?
Form 4 and Form 6 are due the 15th day of the 4th month after the end of the taxable year.
Does an extension also postpone the tax payment?
No. The extension moves the filing date, not the payment date; unpaid tax can accrue penalty and interest.
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