340B Rebate Model Pilot · from 1 January 2027

What the rebate model costs a program your size.

For twenty-five drugs, the 340B discount stops arriving in the purchase price and starts arriving as a rebate that has to be claimed. Enter your annual 340B purchases. Every other value below is a published figure or a stated assumption, and every one of them is yours to change.

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Your program

Two figures. Both are things you already know.

Total annual 340B purchases

Scales every figure on this page. 5.5% of it falls in scope — HRSA's own estimate of the share of 340B sales the Pilot covers.

Wholesaler payment terms30 days
10306090

The single input that decides whether carrying cost is real or close to zero. If a rebate lands before the invoice is due, HRSA's position holds.

Scenario

Moves four rates together: claims denied, claims needing an inquiry, records that do not reconcile, and days of inventory dwell.

The three clocks

None of these is a price. Each one decides how long money sits outstanding.

Submission lag — dispense to filing22 days
12245 · HRSA limit

Acts on the share of the file that pays cleanly, which is the largest share. The only one of the three set inside your organization today. Manufacturer plans must allow at least 45 days.

Exception duration — dispense to resolution82 days
4282365

The program has not bounded this. HRSA has committed to a challenge pathway with specified timeframes and has not published them. 82 days is a 22-day filing lag plus 60 days one covered entity observed under the Maximum Fair Price rebate — a different program, with a working route.

Inventory dwell — purchase to qualifying dispense30 days
090180

Applied only to the ten slow-moving drugs, which carry 1.5% of Medicare patients and 21.9% of the spend. A package bought at WAC earns no rebate until a unit is dispensed.

Price assumption

340B ceiling as a share of WAC15.5%
5%15.5%40%

The input that moves the answer most, and a stand-in. Replace it with your confirmed ceiling prices for the in-scope drugs. A lower share means more cash out at WAC for the same volume. HRSA's own comment record carries reports of 20- to 40-fold increases on the most affected drugs.

Everything else — six more assumptions
Cost of capital1.0%

Deliberately low. Interest is the smaller story; the balance is the larger one.

Filings per year52

The Notice mandates no frequency at all. Filing more often shortens the cash cycle and raises fixed labor.

Separate reports to pull43

One per administrator, pharmacy system and clinic log. Sets the fixed labor, which does not scale with claim volume.

Labor rate$132/hr

HRSA's own figure — a pharmacist's 2024 hourly wage plus overhead.

Average in-scope prescription$784

Proximity's estimate, not a published figure. Sets how many prescriptions the labor lines are counting.

Slow-mover share of spend21.9%

Drawn from Medicare negotiation data and applied to an all-payer receivable — the one place a Medicare-derived share does that here.

Annual recurring cost
Balance outstanding
Not part of the total. Money held at any moment, against the same wholesaler credit line that absorbs the shift to WAC.
Clean claims
Exceptions
Slow-mover dwell
Annual recurring costAmount
Balance outstanding at any momentAmount
What this is. Our model at your scale, not your numbers. One figure here is yours; the rest are published values or our stated assumptions. Six things would make it actually yours — your confirmed ceiling prices, your in-scope spend, your wholesaler terms and credit line, your days of inventory by drug, which of the slow movers actually turn slowly for you, and your payer mix on the in-scope drugs. Each is a report someone already runs.

Those six things are reports someone already runs. We will run this against them with you, and show you where our assumptions were wrong about your program.

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Sources — HRSA, Notice Regarding 340B Rebate Model Pilot Program, 91 FR 48883, 3 August 2026, for the in-scope share, the 45-day filing window, the 10-day payment window, the clock-restart provision, the challenge-pathway commitment, and the labor rate. Covered entity comments filed with HRSA, February to June 2026, for denial rates, inquiry rates, reconciliation shares and observed payment timing. CMS Medicare Drug Price Negotiation Program for the selected drug list and the fast and slow mover split. Values marked as stand-ins are Proximity's own and are stated as assumptions rather than findings.