Wis. Stat. § 342.157: Motor vehicle salvage pools and auction companies to maintain records.

For each motor vehicle sold by a motor vehicle salvage pool or auction company, the motor vehicle salvage pool or auction company shall establish and maintain a record of each sale, including the mileage disclosure of the transferor under s. 342.155. The department shall specify by rule the information that shall be included in such records and the manner in which and the period of time for which the records shall be maintained.