Illinois HB 2840 makes the current workers compensation medical fee schedule inoperative after August 31, 2026. Every payment made on or after September 1, on open claims of any accident year, will be priced under a new Medicare-corridor structure. Self-insured Illinois employers have 19 days to coordinate with their TPAs before the old benchmark disappears.
What the law changes
The new structure sets a floor of 125% of Medicare and a ceiling of 225% for each procedure code and DRG. Services priced below the floor automatically rise to 125%; services above the ceiling are capped at 225%. The Illinois Workers’ Compensation Commission will publish 18 geographic fee schedules: four non-hospital schedules and 14 hospital schedules tied to specific county groupings across the state.
The annual adjustment mechanism also changes permanently. Rather than politically negotiated periodic updates, the new schedule increases each year by half the Consumer Price Index for All Urban Consumers (CPI-U). That replaces a discretionary process with an automatic formula, which changes the long-run severity trend assumption actuaries have historically applied to Illinois WC medical.
Who it affects
Self-insured Illinois employers, public entities, universities, hospitals, logistics and construction firms, and group WC pools with Illinois members. The issue is not prospective pricing alone: every open medical claim on the books will be paid under the new schedule starting September 1, regardless of when the injury occurred. Claims currently reserved at old fee-schedule rates may be under or over their actual liability depending on how the legacy rate compares to the new corridor.
The reserve mechanism
This is a case adequacy problem. Rural Illinois geographic zones where legacy rates ran below 125% of Medicare will require case reserve increases for hospital inpatient claims: those files are now under-reserved by the gap between the old rate and the new 125% floor. Urban and suburban claims where legacy rates already cleared 125% may see limited change or a ceiling effect if rates were above 225%.
The actuarial implication runs beyond open claims. Development triangles calibrated to historical Illinois WC medical data embed the old fee schedule’s pricing curve. Post-September claims follow a structurally different curve. Blending both in a single triangle without a break adjustment will distort paid and incurred development factors, emergence patterns, and every diagnostic metric derived from them. The September 2026 data point is a structural break that needs to be flagged explicitly in the next actuarial report.
The shift to a CPI-U-linked annual adjustment also affects prospective trend assumptions. Actuaries who have used Illinois-specific historical trend data will need to revise the long-run medical severity assumption to reflect the formula rather than the negotiated-update pattern.
See also: the Illinois HB 5228 analysis on WC medical review reserve timing, which covers the companion UR reform bill sent to the governor in June.
What this means for your next review
Before September 1, contact your TPA and confirm it has pulled every open Illinois WC medical claim, identified the applicable geographic schedule for each claimant’s service location, and flagged files where the new corridor would change expected total medical payments. Reserve adjustments should be processed before the schedule flips; adjustments made after September 1 will be more difficult to attribute to the fee schedule change versus ordinary development.
At the next formal reserve study, ask your actuary whether the development triangle includes a break adjustment at the September 2026 data point. Blending pre- and post-reset claim payments without a correction will distort tail factors.
Decision-maker checklist (next 30 days):
- Ask your TPA for a count of open Illinois WC medical claims by geographic schedule region and a reserve variance estimate between old and new rates.
- Confirm your case reserve for hospital inpatient claims in rural geographic zones reflects the new 125% Medicare floor, not the legacy rate.
- Ask your actuary whether the Illinois WC medical development triangle will carry a structural break at September 2026, or whether an adjustment factor will be applied.
- Update your long-run Illinois WC medical severity trend assumption to reflect the CPI-U/2 formula rather than the prior negotiated-update pattern.