IL HB4288

Amends the State Prompt Payment Act to require state agencies to confirm receipt of contractor bills or invoices within 15 business days and transmit approved amounts to the Comptroller within 30 days of receipt

Requires state agencies to make voucher information (voucher number, date, and amount) available electronically within 15 business days of submission to the Comptroller, replacing the previous "promptly" standard

Allows agencies to pay late-payment interest liabilities from any appropriated funds not prohibited for that purpose when federal rules prevent charging interest to the original expenditure account (previously limited to General Revenue Fund)

Establishes a uniform 30-day deadline for agencies to review bills/invoices and notify vendors of any defects, removing the previous distinction between construction and non-construction bills

Eliminates obsolete provisions related to payment timelines that predated State fiscal year 2012, consolidating requirements under the current 90-day payment standard with 1% monthly interest penalties for late payments