Today they released CLAUDE / FABLE 5, a new LLM model. I gave it a Medicare topic that is hard to research and explain.
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Please give me a relatively manageable (digestible) description of the current major Medicare rules regarding Part B budget neutrality. I remember the old SGR sustainable growth rate, SGR is gone, but there are still some rules. There may be some that affect a specialty (e.g. radiology) and others that are global but i'm unsure. I am a Medicare expert but I get confused in THIS area . for fable 5.
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SGR — Medicare's macro control tying aggregate updates to volume growth — died with MACRA in 2015.
What survives is micro budget neutrality:
- Section 1848(c)(2)(B)(ii)(II) requires that RVU revaluations not shift total PFS spending by more than $20 million, forcing zero-sum redistribution across specialties via conversion factor adjustments (or within RVU pools, as with 2026's facility PE change).
- Annual updates are now fixed by statute — 0.75% APM / 0.25% non-APM starting 2026 — routinely supplemented by one-year congressional patches exempt from neutrality.
- Radiology-specific policies (DRA caps, MPPR) are targeted cuts, not neutrality.
- The CLFS, Part B drugs, and OPPS sit outside this system entirely.
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Here's the mental architecture, which I think helps because the confusion usually comes from conflating three different mechanisms that all lived in the same statute.
1. The core rule: RVU budget neutrality (this is the survivor, and the workhorse)
Section 1848(c)(2)(B)(ii)(II) requires that changes CMS makes to relative values — work, practice expense, malpractice — not cause estimated PFS expenditures to rise or fall by more than $20 million in a year.
Note what this is and isn't: it's not a cap on total Part B physician spending. It's a zero-sum constraint on revaluation (when RVUs change). When CMS raises the value of one thing (E/M visits in 2021, the G2211 add-on in 2024), everything else must shrink to pay for it, and the mechanism is an across-the-board adjustment to the conversion factor. So BN is fundamentally a redistribution engine, not a spending-control engine. The famous specialty impact tables in every PFS rule (Table 118 or wherever it lands each year) are the annual scoreboard of who paid for whom.
The perennial grievance: BN is calculated on projected utilization of new or revalued codes, with no true-up. When CMS assumed near-universal billing of G2211 [a budget-up for primary care H&E] and cut the CF accordingly, and actual uptake came in lower, the money didn't come back. It's a one-way ratchet on assumptions.
2. What replaced SGR: the statutory update path (this is where SGR used to live)
SGR was the global spending control — updates tied to whether aggregate volume outran GDP. MACRA killed it in 2015 and replaced it with fixed, legislated updates: 0.5% through 2019, then zero percent for 2020–2025, and starting in CY 2026, the permanent bifurcation: +0.75% for qualifying APM participants and +0.25% for everyone else — hence, for the first time, two conversion factors ($33.57 QP, $33.40 non-QP).
So there is no longer any formula linking updates to volume growth. The "sustainable growth" concept is simply gone; what remains is a fixed dial Congress set in 2015, widely regarded as inadequate against MEI inflation, which is why Congress keeps duct-taping one-year patches on top (3.75% for 2021, 3% for 2022, the 2.93% mid-year fix in 2024, and the 2.5% one-year increase for 2026 via OBBBA Section 71202). Those patches are explicitly exempt from budget neutrality — Congress appropriates real money.
3. The 2026 wrinkles, which show the machinery in action
The CY2026 CF stack is a clean anatomy lesson:
- statutory 2.5% (OBBBA)
- + 0.75%/0.25% MACRA split
- + a positive 0.49% BN adjustment
- + a negative 2.5% "efficiency adjustment" applied to work RVUs of non-time-based services.
- The BN adjustment is positive for once, precisely because CMS cut RVUs: shrinking work RVUs across thousands of codes frees up money inside the neutral pool, which flows back out through a higher CF. Conservation of mass.
Two 2026 redistributions matter for your world.
First, the efficiency adjustment (-2.5% to work RVUs, five-year MEI productivity lookback, refreshing every three years going forward) hits proceduralists and diagnostics; time-based codes, telehealth-list codes, and new codes were exempted.
Second, the facility indirect-PE change — recognizing only half the work-RVU-based indirect PE allocation for facility-setting services — is budget-neutral within the PE pool, so it doesn't touch the CF at all; it just moves money from facility-based to office-based practice (roughly -7% facility, +4% non-facility). This is the second flavor of BN: redistributions executed inside the RVU methodology rather than through the CF.
4. Specialty-specific vs. global
There is essentially no specialty-specific budget neutrality in the PFS — the pool is global, which is exactly why radiology and other RVU-dense specialties experience every primary-care revaluation as a tax.
What radiology has instead are specialty-targeted payment reduction policies that get mistaken for BN: the DRA 2005 cap of imaging technical components at OPPS rates, the multiple procedure payment reduction on imaging professional and technical components, and historically the misvalued-code targets (PAMA/ABLE Act, 2016–2018, now expired) that cut the CF if CMS didn't find enough overvalued codes. Those are cuts, not neutrality — the savings scored to the Treasury, not to other physicians.
5. What's outside the system entirely
Worth keeping the perimeter clear: the CLFS (PAMA market-rate mechanism, no BN), Part B drugs (ASP+6, no BN), and OPPS — which has its own separate budget neutrality (the annual weight scalar, plus episodic dramas like the 340B remedy clawback) but is a different pool with different rules.
The two-sentence version: SGR was macro budget neutrality across time and volume, and it's dead. What survives is micro budget neutrality across the relative-value pie in each year, executed through the CF or within RVU pools — plus a fixed statutory update path that Congress overrides annually because nobody can live on it.
