Wis. Stat. § 626.11: Rate standards.

(1) General. Rates determined under this chapter shall not be excessive, inadequate or unfairly discriminatory.

(2) Excessiveness. Rates determined under this chapter are not excessive merely because a reasonable margin is allowed for a profit.

(3) Adequacy. The commissioner shall approve a minimum adequate pure premium for each classification under which worker’s compensation insurance is written. No insurer writing any insurance specified under s. 626.03 may use a pure premium less than that approved by the commissioner.