Wisconsin
What the Wisconsin authorities publish about business insurance, quoted directly, with a link and a date on every answer.
What the regulator says
Each answer below is what a named authority publishes, quoted so you can check it, with the date we last confirmed it against their page.
When does a Wisconsin employer become subject to the Worker’s Compensation Act?
The Wisconsin Department of Workforce Development states that an employer becomes subject to the Act, and must carry a policy, when the employer employs three or more full-time or part-time employees. The Department publishes a separate wage-based trigger that can bite below that headcount, so three employees is not the only route in.
“The employer employs three or more full-time or part-time employees.”
This is reporting, not advice. Rules change, and the authority above is the one that changes them — confirm your situation there or with a licensed producer before you act on it.