Illinois gives commercial payers and HMOs 30 days to pay and charges 9% annual interest after that. Medicaid managed care plans follow a parallel statute in the Public Aid Code with the same 30-day deadline.
To see what a late Illinois payer owes on a specific claim, use the prompt pay interest calculator.
Illinois prompt pay at a glance
| Statute | 215 ILCS 5/368a (commercial and HMO) and 305 ILCS 5/5-30.1(g) (Medicaid MCOs) |
|---|---|
| Electronic clean claim | Pay within 30 days of receipt of due proof of loss |
| Paper clean claim | Same 30 days. The statute does not distinguish them. |
| Late payment | 9% per year |
| Regulator for complaints | Illinois Department of Insurance (IDOI) |
The statute
Section 368a of the Illinois Insurance Code names insurers, HMOs, managed care plans, PPOs, third-party administrators, IPAs, and PHOs. The HMO Act separately applies § 368a to HMOs through 215 ILCS 125/5-3(a). Medicaid MCOs are governed by 305 ILCS 5/5-30.1(g).
The legislature has not amended § 368a since 2012. Section 5-30.1 was amended several times from 2024 to 2026, most recently effective June 16, 2026, and the prompt-pay subsections remain in place.
Clean-claim payment deadlines
A payer must pay within 30 days after receipt of due written proof of loss, the same for electronic and paper claims (§ 368a(c)). Within that 30 days, it must tell the provider about any known failure to send sufficient documentation.
Medicaid MCOs must pay a claim with all essential information within 30 days, and notify the billing party within 30 days if they cannot adjudicate it (305 ILCS 5/5-30.1(g)).
Not verified: § 368a says “30 days” without the word “calendar”.
Interest and penalties on late payment
Late claims carry interest “at the rate of 9% per year from the 30th day after receipt of such proof of loss” to the date of payment (§ 368a(c)). Interest under $1 need not be paid, and interest owed must be paid within 30 days after the claim is paid.
Medicaid MCOs must pay a penalty at least equal to the § 368a interest, automatically and reported separately (305 ILCS 5/5-30.1(g)).
Which payers the law covers
- Commercial fully insured plans: Covered under § 368a. IDOI says the law does not reach policies purchased in another state.
- HMOs: Covered under § 368a and 215 ILCS 125/5-3(a).
- Medicaid managed care plans: Covered under the separate 305 ILCS 5/5-30.1(g), with complaints handled by HFS rather than IDOI.
- Self-funded ERISA plans: Not covered. IDOI states the Prompt Pay Law does not apply to self-insured employer plans and points providers to the U.S. Department of Labor.
IDOI lists the State Employee Quality Care Plan among plans outside its jurisdiction.
How to file a prompt-pay complaint
Providers file with IDOI online through the IDOI Help Center, or with the provider complaint form by email, fax, or mail, as described on the IDOI provider complaint page. Prompt-pay complaints must include evidence of the claim submission date. File in the provider’s name, not the patient’s.
For a Medicaid MCO, go through the plan’s internal dispute process first, then use the HFS Provider Resolution Portal. Under § 5-30.1(g-8), file no sooner than 30 days after submitting to the MCO and no later than 30 days after an unsatisfactory MCO response, or 60 days after submitting to the MCO.
How prompt pay interacts with timely filing
Illinois sets no statutory filing deadline for commercial or HMO claims, so the window comes from the payer contract, while Medicaid fee-for-service and MCO claims carry a 180-day limit from the date of service (305 ILCS 5/5-30.1(g-12)). The § 368a clock starts at receipt of due proof of loss, so an incomplete claim does not start the 30 days even as the contract filing window keeps running. Our 2026 timely filing guide compares filing limits by payer.
What we could not verify
- Day type for the 30 days in § 368a.
- The IDOI mailing address. The web page lists 4800 Wabash Avenue, Springfield 62711, and the provider form lists 320 West Washington Street, Springfield 62767. Confirm before mailing.
- Whether the state employee plan has its own prompt-pay rule.
- The HFS timely filing rule at 89 Ill. Adm. Code 140.20, which we did not open directly. The 180-day figure is confirmed in the HFS provider handbook and § 5-30.1(g-12).
Sources
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