Assignment and participation
In Original Medicare, participation is a program-level election a provider makes about accepting Medicare-approved amounts as payment in full, while assignment is the related decision — applied per claim by non-participating providers — to accept the Medicare-approved amount for a given service. The two concepts are closely linked but distinct: participating providers agree to accept assignment on all covered services, whereas non-participating providers may accept or decline it claim by claim, within limits set by federal rules. These distinctions shape the allowed amount, how much a beneficiary can be billed, and whether payment is issued to the provider or the patient. Specific dollar figures, fee-schedule amounts, and limiting-charge percentages are set by CMS and vary by service, locality, and year, so this article describes the structure rather than quoting figures.
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Key takeaways
- Participation is a program-level agreement to accept Medicare-approved amounts as payment in full on all covered services; assignment is the acceptance of the approved amount, decided per claim by non-participating providers.
- Participating providers are generally paid directly and cannot balance-bill beyond deductible and coinsurance; non-participating providers who decline assignment face a federally set limiting charge on what the beneficiary can be billed.
- Fee-schedule amounts, limiting-charge percentages, and payment differentials are set by CMS and vary by service, locality, and calendar year, so current values must be confirmed with the applicable Medicare Administrative Contractor.
- Participation status is elected through Medicare enrollment and generally applies within an annual participation cycle; the choice affects fee amounts, assignment obligations, and how remittance is issued.
- These concepts apply primarily to Original Medicare Part B; Medicare Advantage and certain opt-out arrangements follow different contractual rules.
Defining participation and assignment
Although the terms are often used together, participation and assignment answer different questions. Participation asks whether a provider has entered into an agreement with Medicare to accept the program's approved amounts as payment in full across all covered services. Assignment asks, for a specific claim, whether the provider accepts the Medicare-approved amount as full payment for that service. A participating provider effectively answers "yes" to assignment on every covered claim by virtue of the participation agreement, while a non-participating provider retains the ability to answer that question service by service.
- Participation (PAR)
- A program-level election, made through Medicare enrollment, in which a provider agrees to accept assignment on all covered Part B services and to bill only applicable deductible and coinsurance amounts.
- Assignment
- The acceptance of the Medicare-approved amount as full payment for a covered service; for non-participating providers it is decided per claim.
- Non-participating (non-PAR)
- An enrollment status in which the provider has not signed the participation agreement and may accept or decline assignment on each claim, subject to the limiting charge when assignment is declined.
Both statuses are established through Medicare enrollment and billing privileges, and both operate against the Medicare Physician Fee Schedule described in Medicare fee schedules explained.
How status affects fee amounts and payment
Participation status influences three practical dimensions: the fee-schedule amount that applies, whether balance billing is permitted, and to whom Medicare issues payment. CMS structures the fee schedule so that participating and non-participating amounts differ, and non-participating providers who decline assignment are subject to a limiting charge. The exact percentages and amounts are set by CMS and change over time, so they should be verified with the servicing Medicare Administrative Contractor (MAC) rather than assumed.
| Dimension | Participating provider | Non-PAR, accepts assignment | Non-PAR, declines assignment |
|---|---|---|---|
| Assignment applies | Always, on all covered services | On the specific claim | Not on that claim |
| Fee-schedule basis | Participating amount | Non-participating amount | Non-participating amount |
| Balance billing beyond approved amount | Not permitted | Not permitted | Permitted only up to the federal limiting charge |
| Payment recipient | Generally the provider | Generally the provider | Generally the beneficiary |
Values and percentages that populate these categories are set by CMS and vary by service, locality, and year; confirm current figures with the applicable MAC.
The limiting charge is a ceiling, not a fixed number
Billing, remittance, and the beneficiary experience
How a claim is paid and reported depends on assignment. When assignment is accepted, Medicare generally pays the provider directly and the remittance reflects the approved amount, the beneficiary's deductible and coinsurance, and any adjustments. Reading these documents is covered in Reading the Medicare remittance and MSN. When assignment is declined, payment is generally issued to the beneficiary, and the provider collects directly from the patient within the limiting charge.
- Assigned claims: Medicare pays the provider; patient responsibility is limited to deductible and coinsurance on the approved amount.
- Unassigned claims: payment generally goes to the beneficiary; the provider bills the patient up to the limiting charge.
- Regardless of assignment, providers submitting covered Part B claims are generally required to file the claim on the beneficiary's behalf.
- The remittance advice and beneficiary Medicare Summary Notice report the approved amount, adjustments, and patient responsibility.
Claim adjustment and remark codes on the remittance explain how Medicare adjudicated the service, including any assignment-related messaging. Assignment interacts with other Medicare rules as well — for example, when Medicare is not the primary payer under Medicare Secondary Payer (MSP) billing, or when a beneficiary is issued an Advance Beneficiary Notice (ABN) for services that may not be covered.
Electing and changing status
Participation status is chosen during Medicare enrollment and can generally be changed during an annual participation election period defined by CMS. The choice is recorded through the enrollment systems used for Medicare enrollment with PECOS, and the associated participation agreement governs assignment obligations for the cycle. Because the election affects fee amounts, assignment duties, and how payment flows, providers typically weigh it against their patient mix and administrative preferences.
Confirm current status
Verify participation status and effective dates in the Medicare enrollment record, since it governs assignment obligations for the cycle.Review the applicable fee amounts
Compare participating and non-participating fee-schedule amounts and the limiting charge for the relevant locality using MAC-published figures.Understand the annual election window
Changes generally take effect for the following participation year within the window set by CMS; confirm dates with the MAC.Align billing workflows
Ensure claim submission, patient billing, and payment posting reflect assignment status so that limiting-charge rules are not exceeded.
Different rules outside Original Medicare
Frequently asked questions
What is the difference between participation and assignment?
Participation is a program-level agreement to accept Medicare-approved amounts as payment in full on all covered Part B services. Assignment is the acceptance of the approved amount for a specific service. Participating providers accept assignment on every covered claim; non-participating providers decide assignment claim by claim.
Can a non-participating provider bill the patient more than the Medicare-approved amount?
Only up to a federally defined limiting charge, and only when assignment is declined on that claim. The limiting-charge percentage is set by CMS and applied to the non-participating fee-schedule amount, so the dollar ceiling varies by service, locality, and year. Current values should be confirmed with the applicable MAC.
Who receives the Medicare payment on an unassigned claim?
When a non-participating provider declines assignment, Medicare generally issues payment to the beneficiary rather than the provider, and the provider collects from the patient within the limiting charge. On assigned claims, Medicare generally pays the provider directly.
Does participation status affect the fee-schedule amount?
Yes. CMS structures the Medicare Physician Fee Schedule with distinct participating and non-participating amounts, and non-participating providers who decline assignment are additionally subject to the limiting charge. The specific figures are set by CMS and change over time.
How does a provider change participation status?
Participation is elected through Medicare enrollment and can generally be changed during an annual participation election period defined by CMS, recorded via the Medicare enrollment systems. Effective dates and window timing should be verified with the servicing MAC.
Related glossary terms
Definitions that support an understanding of Medicare participation and assignment.
Related reading
Continue with related Medicare billing topics.
Medicare fee schedules explained
How CMS builds participating and non-participating fee-schedule amounts and the limiting charge.
Medicare enrollment and billing privileges
How participation status is established through Medicare enrollment.
Reading the Medicare remittance and MSN
How assignment and payment appear on remittance advice and the beneficiary summary notice.
The Advance Beneficiary Notice (ABN)
How beneficiary notices interact with billing for services that may not be covered.
Medicare Administrative Contractors (MACs)
The contractors that publish locality fee amounts and adjudicate Part B claims.