Wis. Stat. § 229.833: Trust funds.

All moneys received under this subchapter, whether as proceeds from the sale of bonds or from any other source, are trust funds to be held and applied solely as provided in this subchapter. Any officer with whom, or any bank or trust company with which, those moneys are deposited shall act as trustee of those moneys and shall hold and apply the moneys for the purposes of this subchapter, subject to this subchapter and the bond resolution authorizing issuance of the bonds.