40 ILCS 5/21-114
The State Agency upon its own initiative may conduct investigative field audits of the books and payroll records for calendar years prior to 1987 of any political subdivision or retirement system which has adopted coverage. The audits may be conducted at the business office of any participating entity or at any other site mutually convenient to the State Agency and the entity. The State Agency may require covered entities to submit reconciliation statements disclosing total wages and compensation disbursed for all personal services performed during a designated period for comparison with wages included upon reports for which contributions were paid in that same period.
The State Agency may also require, accept and rely upon payroll audits performed by the field staff of any retirement system conducted in accordance with guidelines established by the State Agency, to determine compliance with the reporting and collection of contributions upon covered wages.
The cost of investigative audits conducted by the State Agency under this Section shall be recovered through levy of the annual administrative charge as provided in Section 21-116; however, if the investigative audit should disclose substantial noncompliance requiring an extensive audit, the State Agency may assess audit costs summarily against the noncomplying entity.
40 ILCS 5/21-114