Wis. Stat. § 779.88

Except as provided under s. 779.87 (3), a customer who makes a prepayment under a regulated prepaid maintenance agreement has a lien designated as a prepaid maintenance lien in the amount of the prepayment on all the proceeds contained in the escrow account, including all after acquired proceeds. This lien is preferred to all other liens, security interests and claims on such proceeds except other prepaid maintenance liens which attached at an earlier time.