Wisconsin Business Tax Extension LLC / Partnership – S Corporation – C Corporation – Fiduciary
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Connect with a TaxPro →Wisconsin Business Tax Extension – LLC / Partnership
Wisconsin Extension Payment • LLC / PartnershipWisconsin LLC & Partnership Tax Extension
Wisconsin LLCs and partnerships with Wisconsin source income file Form 3 (Wisconsin Partnership Return) with the Wisconsin Department of Revenue. The return is due March 16, 2026, and a six-month extension to September 15, 2026 is available. Wisconsin automatically honors the federal Form 7004 extension for pass-through entity returns–no separate Wisconsin extension form is required–provided all Wisconsin income tax owed is paid by March 16, 2026.
Extending a Wisconsin LLC or Partnership Return
File IRS Form 7004 before March 16, 2026 to extend the Wisconsin return to September 15, 2026. Pay all Wisconsin tax owed by March 16, 2026 through Wisconsin TAP or by mailing a payment to: Wisconsin Department of Revenue, PO Box 8949, Madison, WI 53708.
Wisconsin automatically honors the federal Form 7004 extension for partnership returns–no separate Wisconsin extension form is required. Wisconsin requires pass-through entities to withhold Wisconsin income tax on the Wisconsin-source income of nonresident members unless the nonresident member files a Wisconsin Form PW-2 waiver. The withholding rate is the highest Wisconsin individual rate (7.65%). The withholding obligation is not extended by the filing extension–amounts must be paid by March 16, 2026.
WI LLC Extension Best Practices
- File IRS Form 7004 before March 16, 2026 to extend the Wisconsin Form 3 return to September 15, 2026–no separate Wisconsin extension form is required.
- Pay all Wisconsin pass-through entity or nonresident withholding tax by March 16, 2026 through Wisconsin TAP or by mail to avoid the 5%/month failure-to-file penalty.
- Remit Wisconsin nonresident member withholding by the original deadline or obtain Form PW-2 waivers from nonresident members before March 16, 2026.
- File the completed Form 3 with the Wisconsin Department of Revenue by September 15, 2026.
Working with a Tax Professional
LLC / Partnership returns carry unique complexities – a licensed CPA or Enrolled Agent can navigate the details and ensure your Wisconsin return is filed accurately and on time.
- Get matched with a verified U.S.-based CPA or Enrolled Agent
- Upload your business documents via secure drag-and-drop
- Review your return with transparent, upfront pricing
- Your TaxPro files the Wisconsin return by September 15, 2026
How to Pay
Wisconsin requires online payment for tax amounts of $750 or more. Submit electronically via the Wisconsin Online Tax Extension Payment portal. For amounts under $750, complete Wisconsin Extension Payment and mail with your payment.
Wisconsin Online Payment Portal
Submit electronically through the Wisconsin Online Tax Extension Payment system. Required for all payments $750 and above.
Wisconsin Extension Payment by Check
Download Wisconsin Extension Payment and mail with your check or money order. Include your EIN and tax year on the check.
PO Box 8949
Madison, WI 53708
Late Filing & Payment Penalties
| Penalty Type | Amount |
|---|---|
| Failure to File | 5% of unpaid tax per month, up to 25% |
| Failure to Pay | 1% per month on unpaid tax |
LLC / Partnership Quick Reference
| State Abbreviation | WI |
| Entity Type | LLC / Partnership |
| Extension Status | Automatic with approved IRS Form 7004 |
| Original Filing Deadline | March 16, 2026 |
| Extended Filing Deadline | September 15, 2026 |
| Payment Due | March 16, 2026 (100% of tax owed) |
| Payment Form | Wisconsin Extension Payment |
| Online Payment | Wisconsin Online Tax Extension Payment |
| State Agency | Wisconsin Department of Revenue |
| Failure to File Penalty | 5% of unpaid tax per month, up to 25% |
| Failure to Pay Penalty | 1% per month on unpaid tax |
Wisconsin Business Tax Extension – S Corporation
Wisconsin Extension Payment • S CorporationWisconsin S Corporation Tax Extension
Wisconsin S corporations with Wisconsin source income file Form 5S (Wisconsin Tax-Option (S) Corporation Franchise or Income Tax Return) with the Wisconsin Department of Revenue. The return is due March 16, 2026, and a six-month extension to September 15, 2026 is available. Wisconsin automatically honors the federal Form 7004 extension–no separate Wisconsin extension form is required–provided all Wisconsin income tax owed is paid by March 16, 2026.
Extending a Wisconsin S Corporation Return
File IRS Form 7004 before March 16, 2026 to extend the Wisconsin return to September 15, 2026. Pay all Wisconsin income tax owed by March 16, 2026. Pay online or mail payments to: Wisconsin Department of Revenue, PO Box 8949, Madison, WI 53708.
Wisconsin S corporations–referred to as "tax-option corporations" under Wisconsin law–are treated as pass-through entities for Wisconsin income tax purposes. Wisconsin requires withholding on the Wisconsin-source income of nonresident shareholders unless the nonresident shareholder files a Wisconsin Form PW-2 waiver. The withholding rate is 7.65% for individuals. Wisconsin also imposes a minimum franchise tax on S corporations–the minimum tax is $25 per year for corporations with gross receipts below $4 million and scales up to $9,800 for the largest corporations.
WI S Corporation Extension Best Practices
- File IRS Form 7004 before March 16, 2026 to extend the Wisconsin Form 5S return to September 15, 2026–no separate Wisconsin extension form is required.
- Pay all Wisconsin S corporation or pass-through entity tax by March 16, 2026 through Wisconsin TAP or by mail to avoid the 5%/month failure-to-file penalty.
- Remit Wisconsin nonresident shareholder withholding by the original deadline or obtain Form PW-2 waivers before March 16, 2026.
- File the completed Form 5S with the Wisconsin Department of Revenue by September 15, 2026.
Working with a Tax Professional
S Corporation returns carry unique complexities – a licensed CPA or Enrolled Agent can navigate the details and ensure your Wisconsin return is filed accurately and on time.
- Get matched with a verified U.S.-based CPA or Enrolled Agent
- Upload your business documents via secure drag-and-drop
- Review your return with transparent, upfront pricing
- Your TaxPro files the Wisconsin return by September 15, 2026
How to Pay
Wisconsin requires online payment for tax amounts of $750 or more. Submit electronically via the Wisconsin Online Tax Extension Payment portal. For amounts under $750, complete Wisconsin Extension Payment and mail with your payment.
Wisconsin Online Payment Portal
Submit electronically through the Wisconsin Online Tax Extension Payment system. Required for all payments $750 and above.
Wisconsin Extension Payment by Check
Download Wisconsin Extension Payment and mail with your check or money order. Include your EIN and tax year on the check.
PO Box 8949
Madison, WI 53708
Late Filing & Payment Penalties
| Penalty Type | Amount |
|---|---|
| Failure to File | 5% of unpaid tax per month, up to 25% |
| Failure to Pay | 1% per month on unpaid tax |
S Corporation Quick Reference
| State Abbreviation | WI |
| Entity Type | S Corporation |
| Extension Status | Automatic with approved IRS Form 7004 |
| Original Filing Deadline | March 16, 2026 |
| Extended Filing Deadline | September 15, 2026 |
| Payment Due | March 16, 2026 (100% of tax owed) |
| Payment Form | Wisconsin Extension Payment |
| Online Payment | Wisconsin Online Tax Extension Payment |
| State Agency | Wisconsin Department of Revenue |
| Failure to File Penalty | 5% of unpaid tax per month, up to 25% |
| Failure to Pay Penalty | 1% per month on unpaid tax |
Wisconsin Business Tax Extension – C Corporation
Wisconsin Extension Payment • C CorporationWisconsin C Corporation Tax Extension
Wisconsin C corporations with Wisconsin taxable income file Form 4 (Wisconsin Corporation Franchise or Income Tax Return) with the Wisconsin Department of Revenue. The return is due April 15, 2026, and a six-month extension to November 15, 2026 is available. Wisconsin automatically honors the federal Form 7004 extension–no separate Wisconsin extension form is required–provided all Wisconsin corporate income tax owed is paid by April 15, 2026. Wisconsin corporate income is taxed at 7.9% flat rate.
Extending a Wisconsin C Corporation Return
File IRS Form 7004 before April 15, 2026 to extend the Wisconsin Form 4 (Wisconsin Corporation Franchise or Income Tax Return) return to November 15, 2026. Pay all Wisconsin corporate income tax by April 15, 2026. Pay online or mail payments to: Wisconsin Department of Revenue, PO Box 8949, Madison, WI 53708.
Wisconsin imposes a franchise tax on corporations doing business in Wisconsin. Wisconsin uses a single-sales-factor apportionment formula for most corporations–only Wisconsin sales are used to apportion income to Wisconsin. Wisconsin also imposes an economic development surcharge on corporations with Wisconsin gross receipts exceeding $4 million–this surcharge is the greater of $25 or 3% of Wisconsin tax liability, with a maximum of $9,800 per year. Wisconsin requires estimated tax payments for corporations with annual Wisconsin tax liability exceeding $500.
WI C Corporation Extension Best Practices
- File IRS Form 7004 before April 15, 2026 to extend the Wisconsin Form 4 return to November 15, 2026–no separate Wisconsin extension form is required.
- Pay all Wisconsin franchise or income tax by April 15, 2026 through Wisconsin TAP or by mail to avoid the 5%/month failure-to-file penalty.
- Confirm the Wisconsin economic development surcharge obligation and include it in the extension payment if applicable.
- File the completed Form 4 with the Wisconsin Department of Revenue by November 15, 2026.
Working with a Tax Professional
C Corporation returns carry unique complexities – a licensed CPA or Enrolled Agent can navigate the details and ensure your Wisconsin return is filed accurately and on time.
- Get matched with a verified U.S.-based CPA or Enrolled Agent
- Upload your business documents via secure drag-and-drop
- Review your return with transparent, upfront pricing
- Your TaxPro files the Wisconsin return by November 15, 2026
How to Pay
Wisconsin requires online payment for tax amounts of $750 or more. Submit electronically via the Wisconsin Online Tax Extension Payment portal. For amounts under $750, complete Wisconsin Extension Payment and mail with your payment.
Wisconsin Online Payment Portal
Submit electronically through the Wisconsin Online Tax Extension Payment system. Required for all payments $750 and above.
Wisconsin Extension Payment by Check
Download Wisconsin Extension Payment and mail with your check or money order. Include your EIN and tax year on the check.
PO Box 8949
Madison, WI 53708
Late Filing & Payment Penalties
| Penalty Type | Amount |
|---|---|
| Failure to File | 5% of unpaid tax per month, up to 25% |
| Failure to Pay | 1% per month on unpaid tax |
C Corporation Quick Reference
| State Abbreviation | WI |
| Entity Type | C Corporation |
| Extension Status | Automatic with approved IRS Form 7004 |
| Original Filing Deadline | April 15, 2026 |
| Extended Filing Deadline | November 15, 2026 |
| Payment Due | April 15, 2026 (100% of tax owed) |
| Payment Form | Wisconsin Extension Payment |
| Online Payment | Wisconsin Online Tax Extension Payment |
| State Agency | Wisconsin Department of Revenue |
| Failure to File Penalty | 5% of unpaid tax per month, up to 25% |
| Failure to Pay Penalty | 1% per month on unpaid tax |
Wisconsin Business Tax Extension – Fiduciary
Wisconsin Extension Payment • FiduciaryWisconsin Fiduciary Tax Extension
Wisconsin trusts and estates with Wisconsin source income file Form 2 (Wisconsin Fiduciary Return for Estates or Trusts) with the Wisconsin Department of Revenue. The return is due April 15, 2026, and a six-month extension to October 15, 2026 is available. Wisconsin automatically honors the federal Form 7004 extension–no separate Wisconsin extension form is required–provided all Wisconsin fiduciary income tax owed is paid by April 15, 2026. Wisconsin fiduciary income is taxed at 3.54% to 7.65% graduated rates.
Extending a Wisconsin Fiduciary Return
File IRS Form 7004 before April 15, 2026 to extend the Wisconsin Form 2 (Wisconsin Fiduciary Return for Estates or Trusts) return to October 15, 2026. Pay all Wisconsin fiduciary income tax by April 15, 2026. Pay online or mail payments to: Wisconsin Department of Revenue, PO Box 8949, Madison, WI 53708.
Wisconsin taxes the income of resident trusts–those administered by a Wisconsin trustee or created by a Wisconsin resident–on all income regardless of source. Nonresident trusts pay Wisconsin tax only on Wisconsin-source income. Wisconsin fiduciary income tax rates follow the individual rate schedule with four brackets. Wisconsin does not require a separate extension form for fiduciary returns–a valid federal Form 7004 automatically extends the Wisconsin Form 2 to October 15, 2026, provided all Wisconsin fiduciary income tax is paid by April 15, 2026.
WI Fiduciary Extension Best Practices
- File IRS Form 7004 before April 15, 2026 to extend the Wisconsin Form 2 fiduciary return to October 15, 2026–no separate Wisconsin extension form is required.
- Pay all Wisconsin fiduciary income tax by April 15, 2026 through Wisconsin TAP or by mail to avoid the 5%/month failure-to-file penalty.
- Confirm the trust's Wisconsin residency classification to determine whether all income or only Wisconsin-source income is subject to Wisconsin fiduciary tax.
- File the completed Form 2 with the Wisconsin Department of Revenue by October 15, 2026.
Working with a Tax Professional
Fiduciary returns carry unique complexities – a licensed CPA or Enrolled Agent can navigate the details and ensure your Wisconsin return is filed accurately and on time.
- Get matched with a verified U.S.-based CPA or Enrolled Agent
- Upload your business documents via secure drag-and-drop
- Review your return with transparent, upfront pricing
- Your TaxPro files the Wisconsin return by October 15, 2026
How to Pay
Wisconsin requires online payment for tax amounts of $750 or more. Submit electronically via the Wisconsin Online Tax Extension Payment portal. For amounts under $750, complete Wisconsin Extension Payment and mail with your payment.
Wisconsin Online Payment Portal
Submit electronically through the Wisconsin Online Tax Extension Payment system. Required for all payments $750 and above.
Wisconsin Extension Payment by Check
Download Wisconsin Extension Payment and mail with your check or money order. Include your EIN and tax year on the check.
PO Box 8949
Madison, WI 53708
Late Filing & Payment Penalties
| Penalty Type | Amount |
|---|---|
| Failure to File | 5% of unpaid tax per month, up to 25% |
| Failure to Pay | 1% per month on unpaid tax |
Fiduciary Quick Reference
| State Abbreviation | WI |
| Entity Type | Fiduciary |
| Extension Status | Automatic with approved IRS Form 7004 |
| Original Filing Deadline | April 15, 2026 |
| Extended Filing Deadline | October 15, 2026 |
| Payment Due | April 15, 2026 (100% of tax owed) |
| Payment Form | Wisconsin Extension Payment |
| Online Payment | Wisconsin Online Tax Extension Payment |
| State Agency | Wisconsin Department of Revenue |
| Failure to File Penalty | 5% of unpaid tax per month, up to 25% |
| Failure to Pay Penalty | 1% per month on unpaid tax |
Extended? Your Wisconsin Business Return Deadline Is Coming Up.
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