Wis. Stat. § 480.16
All downpayments, earnest money deposits or other trust funds received by an auctioneer or auction company on behalf of the auctioneer's or auction company's principal or any other person shall be deposited in a common trust account maintained by the auctioneer or auction company for that purpose in a bank, savings and loan association or credit union which is authorized to do business in this state and is designated by the auctioneer or auction company pending the consummation or termination of the transaction, except that the money may be paid to one of the parties pursuant to an agreement between the parties. The name of the bank, savings and loan association or credit union shall at all times be registered with the department, along with a letter authorizing the department to examine and audit the trust account when the department determines that an examination or audit of the trust account is necessary.
Wis. Stat. § 480.16