CMS’s April 1, 2026 HPT Enforcement: 10th/Median/90th Percentiles Explained

CMS’s Hospital Price Transparency enforcement for updated requirements begins April 1, 2026. For hospitals and health systems, that date is a practical deadline to ensure the machine-readable file (MRF) and related attestation language match the latest CMS requirements.

The core change in the CY 2026 update is how hospitals report payer-negotiated “allowed amounts” for certain negotiated charges that are set using a percentage or algorithm. Instead of using a single point estimate, CMS requires a distribution-based set of values in the MRF: the median plus the 10th and 90th percentile allowed amounts, and the count of allowed amounts used to calculate them.

Hospital Price Transparency: what hospitals must publish

Under federal Hospital Price Transparency rules, each hospital operating in the United States must provide pricing information online in two ways:

A comprehensive machine-readable file with all items and services.
A display of shoppable services in a consumer-friendly format.

CMS audits a sample of hospitals, investigates complaints, and hospitals may face civil monetary penalties for noncompliance.

CY 2026 MRF updates: median plus 10th and 90th percentiles

For CY 2026, CMS finalized (effective January 1, 2026) new MRF data elements when a payer-specific negotiated charge is based on a percentage or algorithm. CMS explains that the median allowed amount replaces the prior “estimated allowed amount” data element, and hospitals should not calculate or encode the “estimated allowed amount” element as of that date.

CMS’s June 2026 HPT Policy FAQs describe the distribution fields hospitals must encode in these scenarios:

Median allowed amount
10th percentile allowed amount
90th percentile allowed amount
Count of allowed amounts used to calculate the median and percentiles

How CMS expects hospitals to calculate the distribution

Use a contiguous lookback window (12 to 15 months)

CMS instructs hospitals to use a lookback period of no less than 12 months and no longer than 15 months prior to posting the MRF. CMS also notes this window must be contiguous.

When the percentile lands between observed values, use “next highest observed”

CMS addresses a common data edge case: if a calculated percentile value falls between two observed allowed amounts, hospitals should use the next highest observed value.

Zero-dollar remittances and “no claims” scenarios

CMS’s FAQs spell out two related data-quality scenarios:

Zero-dollar remittances: CMS indicates those should be excluded from the count of allowed amounts. ([cms.gov](CMS))
No claims during the 12–15 month lookback: If the payer-specific negotiated charge is based on an algorithm or percentage that cannot be fully and completely calculated as a dollar value, CMS instructs hospitals to encode ‘0’ for the count of allowed amounts, leave the median/10th/90th fields blank, and encode explanatory information in the appropriate notes field. ([cms.gov](CMS))

Attestation: CMS emphasizes “true, accurate, and complete”

Beyond the numbers, CMS is emphasizing accountability. CMS finalized an MRF attestation requiring hospitals to attest that, to the best of its knowledge and belief, the hospital included all applicable standard charge information and that the information encoded is true, accurate, and complete. CMS also requires identifying the hospital chief executive officer, president, or senior official designated to oversee the encoding.

When enforcement begins

CMS says enforcement of the new and updated Hospital Price Transparency requirements finalized in the CY 2026 OPPS/ASC final rule begins April 1, 2026. CMS also describes this as a time-limited enforcement delay to give hospitals time to update systems, review, validate, and post the MRF.

What patients can and can’t do with 10th/median/90th percentiles

The percentiles are meant to show variation better than a single number—but they are still allowed amounts derived from a historical distribution. They are not a guarantee of a specific patient’s final out-of-pocket amount for a particular date of service.

Two practical takeaways matter for everyday decision-making:

Out-of-pocket totals depend on benefit design. The AHA emphasizes that patients often still lack certainty about their expected out-of-pocket costs for a course of treatment. ([aha.org](Aha))
Transparency data may not reflect the plan rules that generate the payment. The AHA notes that the machine-readable files show rates, but stakeholders still need the algorithms and rules health plans apply to generate the actual payment amount. ([aha.org](Aha))

Patient access and affordability context

Price transparency is one piece of affordability. CDC’s work on “unmet need” highlights that cost barriers can contribute to people delaying care or not getting needed medical services.

CMS enforcement attention is also ongoing in the public eye. For example, Associated Press reported on warning letters to hundreds of hospitals related to pricing information—illustrating the compliance stakes as systems prepare for the April 1, 2026 enforcement inflection point.

What readers can do now

For hospitals and health systems

Audit your MRF build logic for the four CY 2026 elements tied to the median/10th/90th percentiles and the count of allowed amounts. ([cms.gov](CMS))
Validate the lookback window is contiguous and within the 12-to-15-month boundaries CMS describes. ([cms.gov](CMS))
Test edge cases (e.g., zero-dollar remittances and “no claims” handling) so outputs and notes match CMS FAQs expectations. ([cms.gov](CMS))
Operationalize attestation by aligning governance, documentation, and the identity of the senior attester overseeing encoding. ([cms.gov](CMS))

For patients and patient-support teams

Ask what the distribution represents: median and percentile allowed amounts are based on historical remittance distributions, not a personalized out-of-pocket prediction.
Confirm benefit details (deductibles, coinsurance/copays, and in-network vs. out-of-network status) that determine your final cost.
Use transparency data as a starting point for cost-shopping questions, but expect that actual bills can still vary by plan terms and claim processing.

Bottom line: April 1, 2026 is the enforcement inflection point. The update’s distribution-based allowed-amount fields—and the “true, accurate, and complete” attestation expectations—make data-quality governance a central compliance focus for hospitals.

Key sources

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