Key figures
Wisconsin compliance
2026, with sources
Registering a Delaware corporation
A Delaware corporation transacting business in Wisconsin registers with the Department of Financial Institutions; DFI lists the fee for a foreign business corporation as $100+. After that, a foreign corporation files an annual report in the first calendar quarter of every year after it registers, $65 online. DFI’s due date for foreign entities is March 31 regardless of when they registered.
With the Department of Revenue, a business registers once for the taxes it will collect or pay (withholding, sales and use) and renews its Business Tax Registration certificate for a $10 fee.
Returns and the surcharge
The Wisconsin franchise or income tax return is due with the federal return, on the 15th day of the 4th month after year end. A federal extension automatically extends Wisconsin to 30 days after the federal extended date — mid-November for a calendar-year company — with a copy of the federal extension attached. Without a federal extension, Wisconsin gives seven months.
Corporations with $4 million or more of gross receipts add the economic development surcharge to the same return.
Unclaimed property
Wisconsin’s unclaimed property program sits inside the Department of Revenue. Holder reports and payments are due November 1 for the period ending June 30, with a 60-day extension requestable in September and October through My Tax Account, and a 15% penalty on property not paid or delivered on time. Most holders file only when they have something to report; negative reports are required from financial institutions, utilities and life insurers with a Wisconsin presence.
Deadlines
- First calendar quarter — by Mar 31Foreign corporation annual report to DFI ($65 online)Annual report
- Apr 15Franchise or income tax return (calendar year)Form 4 / Form 6
- Nov 1Unclaimed property report and payment for the period ending June 30
The federal baseline
This page covers what Wisconsin adds. The federal rules underneath it apply here too.
Common questions
When is the Wisconsin annual report due for a Delaware corporation?
Every year, in the first calendar quarter — by March 31 — starting the year after registration. Domestic Wisconsin corporations file in the quarter of their incorporation anniversary instead. It costs $65 online for a foreign business corporation.
Do we file an unclaimed property report if we have nothing to report?
Not usually. Wisconsin requires negative reports from financial institutions, utilities and life insurance companies with a physical presence in Wisconsin; other holders report when they have property. Reports and payments are due November 1 for the period ending June 30.
Compliance next door
- ILIllinois complianceIllinois requires an application for authority, a $75 annual report with franchise tax (first $10,000 exempt), Form IL-1120 and an annual unclaimed property report.
- IAIowa complianceRegister with the Secretary of State for $100, file a $60 biennial report by April 1 of even years, and file the IA 1120 by April 30. No franchise tax applies.
- MIMichigan complianceMichigan needs a $60 certificate of authority, a $25 annual report each May 15, a CIT return due April 30 and an unclaimed property report each July 1.
- MNMinnesota complianceMinnesota asks for a certificate of authority ($150 plus a $50 filing fee), a $115 annual renewal, the M4 with its minimum fee, and an unclaimed property report before November 1.
More of the Wisconsin guide
- AccountingAccounting and state tax in WisconsinCorporate tax, conformity to federal rules, apportionment and what it does to your books
- ReceivablesReceivables and sales tax in WisconsinSales tax registration, economic nexus, whether SaaS is taxable, and collecting from customers
- PayablesPayables and contractors in WisconsinPaying vendors and contractors: 1099 filing, use tax, contractor tests and withholding
- PayrollPayroll taxes and employer rules in WisconsinWithholding, unemployment insurance, paid leave, minimum wage and the rules on paydays
- AdvisoryAdvisory: credits and decisions in WisconsinCredits, incentives and the decisions that are cheaper to get right the first time
Sources
Checked against each agency’s own page on . Rates and thresholds change, usually on January 1.
General information for US companies, not tax, legal or accounting advice for yours. Rules and thresholds change; confirm the specifics with a CPA or the agency before you act on them.