Medicare: Participating, Non-Par, Not Enrolled

Last updated: August 18, 2026.

Medicare enrollment and billing status can be easy to conflate. Bomi handles therapist billing and credentialing so practices can confirm the claim path before a status mistake turns into unpaid sessions or an unexpected patient balance.

For a therapist or behavioral-health practice, “participating,” “non-participating,” and “not enrolled” are not three versions of the same thing. The first two are payment choices available to an enrolled Medicare provider. The third means the normal provider billing path is not open.

Scope: This guide covers Original Medicare Part B professional claims paid under the Medicare Physician Fee Schedule (MPFS). Medicare Advantage plans have their own network, claims, and payment rules.

The Three Statuses in One Minute

Participation Is Not the Same as Enrollment

Enrollment is the gate that gives a provider Medicare billing privileges. Participation is an assignment election made after, or as part of, enrollment. That means an enrolled provider can be participating or non-participating, while a provider who is not enrolled is outside the normal provider-claim lane altogether.

This is especially important when a clearinghouse rejection or unpaid claim is described as a “non-par issue.” Non-participating status does not prevent claim submission. Missing enrollment, an inactive billing privilege, a missing group enrollment, or an incomplete reassignment relationship can.

What Accepting Assignment Means

When a provider accepts assignment, the provider agrees to accept the Medicare-approved amount as payment in full for the covered service. The provider can collect the applicable deductible and coinsurance, but cannot balance bill the patient above the allowed amount.

Assignment also determines who receives Medicare’s payment. On an assigned claim, Medicare pays the provider. On an unassigned claim from a non-participating provider, Medicare pays the beneficiary instead. CMS explains the claim and payment difference.

Participating: Assignment on Every Claim

A participating provider is enrolled and has signed a CMS-460 Medicare Participating Physician or Supplier Agreement. The provider agrees to accept assignment for all Medicare-covered services furnished to Medicare patients.

• Can you file claims? Yes. The provider files assigned claims with Medicare.

• Who does Medicare pay? The provider or supplier that submitted the assigned claim.

• What rate applies? The full applicable MPFS allowed amount—often described as 100% of the MPFS amount.

• What can the patient owe? The applicable deductible and coinsurance or copayment, but no amount above the Medicare-approved charge for the covered service.

“100% of MPFS” does not mean Medicare pays 100% of the bill. For most codes, after the deductible is met, Medicare generally pays 80% of the allowed amount and the patient is responsible for 20%. It also does not erase provider-type or service-specific payment adjustments. Use the applicable fee schedule amount for the code, locality, setting, and provider type.

Non-Participating: Still Enrolled, Still Billing

A non-participating provider is enrolled in Medicare but has not agreed to accept assignment on every claim. CMS automatically treats newly enrolled providers as non-participating unless they submit CMS-460.

The provider still submits Medicare claims. The difference is that the provider chooses assignment claim by claim.

When the Non-Participating Provider Accepts Assignment

• The provider files an assigned claim and accepts the Medicare-approved amount as payment in full.

• The allowed amount is 95% of the applicable participating MPFS amount for services paid under the PFS.

• Medicare pays the provider directly, and the patient owes the applicable deductible and coinsurance based on that lower allowed amount.

When the Non-Participating Provider Does Not Accept Assignment

• The provider files an unassigned claim. Non-assignment is not permission to skip claim filing for a Medicare-covered service.

• The provider may ask the patient to pay the full charge upfront.

• The charge cannot exceed the limiting charge: 115% of the non-participating fee schedule amount.

• Because the non-participating amount is 95% of the participating amount, the limiting charge is 109.25% of the participating MPFS amount (95% × 115%).

• Medicare sends its payment to the patient, not the provider. The patient uses that reimbursement against what they already paid or still owe the practice.

A $100 Example

Assume the applicable participating MPFS amount is $100 after any provider-type or service adjustments, the service is covered, and the patient has met the deductible:

1. Participating claim: The allowed amount is $100. Medicare generally pays $80 to the provider, and the patient owes $20.

2. Non-participating, assigned claim: The allowed amount is $95. Medicare generally pays $76 to the provider, and the patient owes $19.

3. Non-participating, unassigned claim: The limiting charge is $109.25. The provider may collect up to that amount from the patient, and Medicare generally sends $76 to the patient. If the provider charged the maximum, the patient’s net cost would be up to $33.25.

This example is for understanding the status math. Deductibles, secondary coverage, claim-specific payment rules, and the provider’s actual charge can change the final dollars.

Not Enrolled: No Normal Provider-Claim Path

A provider who is not enrolled cannot submit the service through the normal Medicare provider-claim process or receive direct Medicare reimbursement through that process. This is not the same as being non-participating.

The first step is to verify the individual enrollment, group enrollment, reassignment, effective date, and any pending application. If enrollment is later approved, check the official effective billing date and any applicable retrospective billing window before deciding that earlier dates cannot be billed.

In limited situations, a beneficiary may submit CMS-1490S as a patient claim when the provider cannot file or is not enrolled. That is not a normal provider claim, does not enroll the provider, and does not create direct Medicare reimbursement for the practice. Medicare may pay the patient or may deny the claim. Read our guide to CMS-1490S and unenrolled Medicare providers for the narrow beneficiary-submitted path.

Opted Out Is a Separate Legal Posture

A provider who has formally opted out is not simply “not enrolled.” Opt-out involves specific Medicare rules and private contracts with beneficiaries, and Medicare generally will not pay for the opted-out provider’s services except in emergencies. That legal posture is outside the scope of this participation-status guide. Medicare.gov explains opt-out at a high level.

How a Newly Enrolled Provider Elects Participating Status

A newly enrolling therapist, group, or other eligible provider can submit CMS-460 with the Medicare enrollment application. If the enrollment is already approved, CMS gives the newly enrolled provider 90 days from enrollment to decide whether to participate and send CMS-460 to the Medicare Administrative Contractor (MAC).

1. Complete CMS-460 using the name and Medicare billing information under which the claims will be submitted.

2. Send it to your MAC, not CMS headquarters. CMS warns that sending the form to CMS instead of the MAC delays processing.

3. File it with enrollment or within the 90-day new-enrollee window. CMS-460 instructions say participation becomes effective on the filing date.

4. Confirm the status after processing. Do not assume the participation election is active merely because the form was uploaded or mailed.

If a newly enrolled provider does nothing, CMS says the provider remains non-participating. After the new-enrollee window, an existing provider generally changes participation status during Medicare’s annual participation enrollment period, usually from mid-November through December 31 for the following calendar year. Confirm exact dates and submission instructions with the MAC.

Bomi workflow note: New Medicare approvals should be checked for participation status immediately. When participating status is intended, CMS-460 should be treated as part of enrollment closeout—not as paperwork to revisit after claims start paying at the non-participating rate.

Practice Checklist

• Confirm that the coverage is Original Medicare, not Medicare Advantage.

• Verify enrollment and billing privileges before deciding the provider is participating or non-participating.

• Confirm whether CMS-460 was accepted and which billing entity or NPI the agreement covers.

• For a non-participating claim, document the assignment choice before collecting from the patient.

• Calculate the limiting charge from the non-participating fee schedule amount, not from the practice’s private-pay fee.

• Explain clearly whether Medicare will pay the practice or reimburse the patient.

Bottom Line

Participating and non-participating providers are both enrolled and can bill Medicare. Participating providers accept assignment on every claim and use the full applicable MPFS allowed amount. Non-participating providers choose assignment claim by claim, use a 95% allowed amount, and can use the limiting charge only on unassigned claims, where Medicare pays the patient directly.

A provider who is not enrolled is in a different category: the normal provider-claim path is not available. Confirm enrollment first, then participation status, then assignment. That order prevents most of the expensive misunderstandings.

This article is general billing education, not legal, compliance, or payer-specific advice. Confirm current CMS instructions and your MAC’s requirements before making enrollment, participation, collection, or private-contract decisions.

Sources

• CMS: Annual Medicare Participation Announcement

• CMS: PFS Quick Reference Search Guide

• CMS: Form CMS-460 and instructions

• CMS: Become a Medicare Provider or Supplier

• Medicare.gov: Assignment, non-participating providers, and opt-out providers

Related Bomi Guides

• How to Credential Medicare as a Therapist LLC

• Authorize Your Biller for Medicare Enrollment

• CMS-1490S and Unenrolled Medicare Providers