Wis. Stat. § 779.16
All moneys, bonds or warrants paid or to become due to any prime contractor or subcontractor for public improvements are a trust fund only in the hands of the prime contractor or subcontractor to the amount of all claims due or to become due or owing from the prime contractor or subcontractor for labor, services, materials, plans, and specifications performed, furnished, or procured for the improvements, until all the claims have been paid, and shall not be a trust fund in the hands of any other person. The use of any such moneys by any prime contractor or subcontractor for any other purpose until all claims, except those which are the subject of a bona fide dispute and then only to the extent of the amount actually in dispute, have been paid in full or proportionally in cases of a deficiency, is theft by the prime contractor or subcontractor of moneys so misappropriated and is punishable under s. 943.20. If the prime contractor or subcontractor is a corporation, limited liability company, or other legal entity other than a sole proprietorship, such misappropriation also shall be deemed theft by any officers, directors, members, partners, or agents responsible for the misappropriation. Any of such misappropriated moneys which have been received as salary, dividend, loan repayment, capital distribution or otherwise by any shareholder, member, or partner not responsible for the misappropriation shall be a civil liability of that person and may be recovered and restored to the trust fund specified in this subsection by action brought by any interested party for that purpose. Except as provided in this subsection, this section shall not create a civil cause of action against any person other than the prime contractor or subcontractor to whom such moneys are paid or become due. Until all claims are paid in full, have matured by notice and filing or have expired, such money, bonds and warrants shall not be subject to garnishment, execution, levy or attachment.
Wis. Stat. § 779.16
A fiduciary relationship exists between a prime contractor and subcontractor when the prime contractor has received payment for a public improvement. Loehrke v. Wanta Builders, 151 Wis. 2d 695, 445 N.W.2d 717 (Ct. App. 1989). Misappropriation of funds under this section was a nondischargeable debt in bankruptcy. Matter of Thomas, 729 F.2d 502 (1984).