On July 2, 2026, CMS issued its calendar-year 2027 Hospital Outpatient Prospective Payment System (OPPS) and Ambulatory Surgical Center proposed rule, CMS-1850-P (CMS fact sheet). The headlines are a 2.4% payment update, the removal of 637 procedures from the Inpatient-Only list, and a site-neutral cut that would pay most off-campus outpatient MRI and CT without contrast at roughly 40% of the usual OPPS rate. Trade press reads this as a hospital-revenue story. For self-insured employers, it is something narrower and more direct: a reset of the unit cost buried in your workers’ compensation medical reserves.
Why a Medicare rule moves WC reserves
Roughly 44 states run a workers’ compensation medical fee schedule, and many peg hospital-outpatient and ambulatory-surgical reimbursement directly to Medicare OPPS base rates and relative weights (see NCCI’s primer on Medicare fee schedules and WC). Georgia’s State Board of Workers’ Compensation, for example, builds its facility schedule on OPPS methodology, and the federal OWCP program has paid on an OPPS basis since 2014. When CMS changes the OPPS base, the allowed amount for an outpatient procedure on a comp claim moves with it in every pegged state, without a single state legislature lifting a finger.
That is the transmission line. The lever it moves is medical severity, specifically unit cost per service, and behind it, case-reserve adequacy on open claims.
Who it affects
Self-insured employers, single-parent and group captives, and public-entity pools carrying WC exposure in OPPS-pegged states. The impact is uneven by design: an employer concentrated in a state that pegs to OPPS sees the full pass-through, while one in a state that sets its own independent base rates (California’s OMFS, which updates on its own schedule) sees little from this rule. A national self-insured with mixed-state payroll sits somewhere in between, and a blended medical-trend assumption will smear the effect until someone splits it out.
The reserve mechanism
Two pieces matter. First, the 2.4% general update (a 3.2% market-basket increase net of a 0.8-point productivity cut) nudges outpatient facility and surgical unit costs up in pegged states. Second, and cutting the other way, the site-neutral imaging cut: CMS estimates paying off-campus MRI and CT without contrast at the physician-fee-equivalent rate would reduce spending by about $190 million and beneficiary cost-sharing by about $70 million, roughly $260 million combined in 2027 (Holland & Knight analysis). Diagnostic imaging is an early, high-frequency line item on soft-tissue and back claims, so in pegged states this pulls diagnostic severity down even as the general update pushes facility cost up. The 637 Inpatient-Only removals push more surgical care into the outpatient and ASC setting, shifting where WC facility dollars land and, secondarily, changing hospital and ambulatory-surgical professional-liability claim mix.
Where this shows up in your reserves
On the medical column of your WC development triangle for accident year 2027, and specifically in the paid-severity trend for outpatient facility and diagnostic services. Do not expect it in 2026. State schedules adopt OPPS updates on their own calendars, so the effect emerges as AY2027 develops, not on the day the final rule lands. That lag is exactly why the impact of a federal outpatient rule is routinely underestimated in the year it arrives.
What this means for your next review
Ask your actuary to confirm the medical-trend assumption distinguishes OPPS-pegged states from independent-fee-schedule states, rather than applying one blended factor. This rule stacks on the CY2027 physician fee cut already flowing into pegged-state professional charges, and echoes the outpatient-versus-ASC payment gap WCRI has flagged. See our explainer on workers’ compensation IBNR for where a unit-cost shift lands in the estimate, and our reserve diagnostic guide for reading the severity signal.
Decision-maker checklist
- Ask whether your WC medical trend splits OPPS-pegged from independent-schedule states.
- Confirm your TPA data extract flags state of jurisdiction at the claim level.
- Test how a site-neutral MRI cut moves diagnostic severity in your pegged-state claims.
- Note the August 31, 2026 comment deadline; self-insured employers rarely engage it.
- Flag accident-year 2027 for a separate look once states adopt the updated OPPS base.
Sources
- CMS CY2027 OPPS/ASC Proposed Rule fact sheet (CMS-1850-P)
- Holland & Knight, CMS Issues Sweeping CY 2027 Hospital OPPS Rule
- Morgan Lewis Health Law Scan, CMS Proposes Major Changes to Medicare Outpatient Payments
- NCCI, Medicare Fee Schedules and Workers Compensation
- Georgia SBWC medical fee schedules (OPPS methodology)