What actually happens
An employee who lives in Minnesota and performs work in Wisconsin sits in two tax systems at once. The residence state claims the right to tax all of a resident's income wherever earned; the work state claims the right to tax income sourced within its borders. Absent an agreement, both claims stand, and the conflict is resolved after the fact through a credit on the resident return rather than up front in payroll.
When Wisconsin withholding starts
Wisconsin applies a de minimis test $1,500 of in-state wages before nonresident withholding begins. Per Wisconsin Publication 166 (Withholding Tax Guide): an employer need not withhold Wisconsin tax from a nonresident employee where the employer can reasonably expect the employee's annual Wisconsin earnings to be less than $1,500; once the estimate exceeds $1,500 the employer must withhold from wages paid thereafter. Does not apply to interstate air carriers. Wisconsin does NOT accept the federal Form W-4 -- every newly hired employee must complete Form WT-4.
The trap is that thresholds are usually retroactive to the first day once crossed. An employee who spends 40 days in a 30-day-threshold state does not owe tax on 10 days; they owe it on all 40, and the employer is the one who failed to withhold.
Unemployment insurance goes to one state only
Income tax can be split between states. Unemployment insurance cannot. Under the localization test used by every state, an employee whose services are performed entirely in Wisconsin is covered by Wisconsin for unemployment purposes, and all wages are reported there — regardless of where they live, where you are headquartered, or which state's income tax you withhold. Wisconsin's 2026 taxable wage base is $14,000. The four-factor test in order.
What you have to register for
| Obligation | State | Agency |
|---|---|---|
| Income tax withholding | Wisconsin | Wisconsin Department of Revenue |
| Unemployment insurance | Wisconsin | Wisconsin Department of Workforce Development (DWD) |
Frequently asked
Do Wisconsin and Minnesota have a reciprocal tax agreement?
No. There is no reciprocal agreement between Wisconsin and Minnesota. Wisconsin taxes wages earned in the state by nonresidents, and Minnesota taxes the same wages as resident income while allowing a credit for tax paid to Wisconsin.
Which state's income tax should be withheld?
Wisconsin, as the state where the work is performed. Minnesota also taxes the income as a resident, but the employee claims a credit on the Minnesota return for tax paid to Wisconsin.
Which state gets the unemployment insurance wages?
Wisconsin. Unemployment coverage is never split between states for a single job. The localization test assigns the whole job to the state where services are performed, which here is Wisconsin, regardless of residence or where the employer is headquartered.
How many days can an employee work in Wisconsin before withholding starts?
Wisconsin applies a de minimis test of $1,500 in wages. Once the limit is crossed, most states require withholding on all in-state wages for the year, not just the excess.