State of Wisconsin – Prompt Payment Law
(Section 16.528, Wisconsin Statutes - https://docs.legis.wisconsin.gov/statutes/statutes/16/III/528)
Wisconsin's prompt payment law requires that state agencies make payments (issue a check or deposit an ACH payment) no later than 30-days from receipt of a properly-completed invoice (or receipt of the goods or services if later). If an agency makes their payment after that date, the agency is required to add interest to the payment in the amount of 12%, compounded monthly. Therefore, vendors (aka “Suppliers") that provide goods or services to Wisconsin state agencies may not add “late fees", “penalties" or any other additional fees to an invoice, regardless of when the State makes the payment. If a Supplier incorrectly adds such a fee, the invoice will be returned to the Supplier, and the Supplier will be required to re-issue a corrected invoice – which could further delay the State's payment.
Below are two examples of how this statute will be applied to State payments. Please note that the State of Wisconsin will return all invoices that are not properly-completed. Requirements for a properly-completed invoice may be found on this website: Properly-Completed Invoice
Example #1 – A properly-completed Supplier invoice arrives at the State 5 days after the Supplier's invoice date:
| Processing Step | Date |
| Supplier invoice date | 5/1/2019 |
| Date the properly-completed invoice is received by the state | 5/6/2019 |
Prompt Payment Date (5/6/2019 + 30 days) (date the check must be mailed OR the ACH payment must be deposited to Supplier's bank account) | 6/5/2019 |
Example #2 – Supplier submits an invoice that is not properly-completed (i.e. the invoice does not include a required element, such as an invoice number, or it contains a late fee or penalty). The invoice is returned to the Supplier and then the Supplier submits a revised, properly-completed invoice:
| Processing Step | Date |
| Supplier invoice date | 5/1/2019 |
| Date the invoice that IS NOT properly-completed is received by the State (i.e. it is missing a required element or it included an improper penalty or late fee). | 5/3/2019 |
| Date the invoice is returned to the Supplier for revision | 5/6/2019 |
| Date the revised, properly-completed Invoice is received by the State | 5/10/2019 |
Prompt Payment Date (5/10/2019 + 30 days) (date the check must be mailed OR the ACH payment must be deposited to Supplier's bank account) | 6/9/2019 |
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