Wis. Stat. § 102.38: Records and reports of payments.

Every insurance company that transacts the business of compensation insurance, and every employer who is subject to this chapter, but whose liability is not insured, shall keep a record of all payments made under this chapter and of the time and manner of making the payments and shall furnish reports based upon these records and any other information to the department as the department may require by rule or general order, in a format approved by the department.