Wis. Stat. § 16.528

(b) If a subcontractor is not paid in a timely fashion, the principal contractor shall pay interest on the balance due from the 8th day after the principal contractor’s receipt of any payment from the agency, at the rate specified in s. 71.82 (1) (a) compounded monthly. (c) Subcontractors receiving payment under this subsection shall pay lower-tier subcontractors, and be liable for interest on late payments, in the same manner as principal contractors are required to pay subcontractors in pars. (a) and (b). (3) Exceptions. Subsection (2) does not apply to the following: (a) Any portion of an order or contract under which the payment is made from federal moneys. (b) An order or contract that is subject to late payment interest or another late payment charge required by another law or rule specifically authorized by law. (c) An order or contract between 2 or more agencies except if the order or contract involves prison industries. (d) An order or contract for services which provides for the time of payment and the consequences of nontimely payment. (e) An order or contract under which the amount due is subject to a good faith dispute if, before the date payment is not timely, notice of the dispute is sent by 1st class mail, personally delivered or sent in accordance with the procedure specified in the order or contract. In this paragraph, “good faith dispute” means a contention by an agency that goods delivered or services rendered were of a lesser quantity or quality than ordered or specified by contract, were faulty or were installed improperly; or any other reason giving cause for the withholding of payment by the agency until the dispute is settled. (f) A contract under s. 977.08 (3) (f). (4) Appropriation from which paid. An agency which pays interest under this section shall pay the interest from the appropriation for administration of the program under which the order or contract was made or entered into unless payment from that appropriation is prohibited. Notwithstanding ss. 20.115 to 20.765, if payment from the appropriation for administration of the program is prohibited, the interest payment shall be made from a general program operations appropriation of the agency determined by the agency. If the program is administered from more than one appropriation, the interest payment shall be made from the appropriation or appropriations for program administration determined by the agency. (5) Reports of interest paid. Annually before October 1, each agency shall report to the department the number of times in the previous fiscal year the agency paid interest under this section, the total amount of interest paid and the reasons why interest payments were not avoided by making timely payment. (6) Attorney fees. Notwithstanding s. 814.04 (1), in an action to recover interest due under this section, the court shall award the prevailing party reasonable attorney fees. History: 1985 a. 300; 1987 s. 312 s. 17; 1987 a. 399; 1989 a. 233; 1991 a. 39; 1995 a. 27, 241; 1999 a. 150 s. 672; 2001 a. 16; 2001 a. 30 s. 108; 2005 a. 74, 335; 2007 a. 20, 97; 2009 a. 28; 2011 a. 7, 10; 2013 a. 20; 2015 a. 55.