Guide

Participation, non-par, opt-out: the three Medicare postures

Summary

Medicare gives a solo three postures. Participation means accepting assignment on every claim and being paid directly from the Medicare-approved amount. Non-participation lets you decide assignment claim by claim and bill the patient above that amount, up to a federal cap, from a different fee schedule. Opting out means private contracts with your patients and billing nothing through Medicare for a set term. Which fits turns on your payer mix, your billing tolerance, and the actual dollar figures you look up for your codes.

By Gale Editorial · Updated 2026-07-26. Every figure cited to a dated source. How we write.

Participation, non-par, and opt-out: what separates them

Medicare gives a solo practice three postures, and they differ on three things: whether you accept assignment, whether you can bill the patient more than Medicare's approved amount, and whether you bill Medicare at all. Participation is the all-in option, non-participation is a claim-by-claim middle path, and opting out leaves the program for private contracts. The right one depends on your payer mix and the actual figures you look up for your codes 1Ref 1Centers for Medicare & Medicaid Services (2026).Physician Fee Schedule Search.That CMS publishes a public Physician Fee Schedule lookup where a clinician enters a code and locality to read the Medicare-approved amount, its RVUs, and payment indicators — the method for finding the binding figures behind the participation decision instead of relying on a remembered number..

The cleanest way to hold the three in your head is a single comparison, kept qualitative on purpose — the dollar amounts belong in a lookup, not in your memory:

Posture	Takes assignment?	Can bill the patient above the approved amount?	Bills Medicare directly?
Participation	Always	No	Yes
Non-participation	Claim by claim	Yes, up to a federal cap	On assigned claims
Opt-out	Not applicable	The private contract sets the fee	No — nothing goes through Medicare

Everything else in this decision is a consequence of those three columns. The sections below take each posture in turn, then cover the two things that sit underneath the choice for every solo: whether you can enroll in the first place, and how the choice touches MIPS and the figures you have to look up. None of it is a moral question about being a good Medicare citizen; it is a question about how your specific panel gets paid and how much billing work you are willing to do.

Participation: accepting assignment on every claim

Participating means signing an agreement to accept assignment on all of your Medicare claims. Assignment is a promise to take Medicare's approved amount as payment in full: Medicare pays its share directly to you, you collect the patient's coinsurance and any unmet deductible, and you never bill the patient for the difference between your charge and the approved amount. It is the simplest posture to run and the one most patients assume they are getting.

The appeal for a solo is administrative. Payment comes to you rather than to the patient, so you are not chasing a reimbursement the patient already received and spent. You appear in Medicare's directory as a participating provider, which matters if referrals or plan directories drive your patients to you. And because you have agreed to assignment across the board, there is no per-claim decision to make and no limiting-charge arithmetic to track on each visit — the billing is the same every time.

The cost is that you accept Medicare's amount as it stands. You cannot recover more from the patient when the approved amount is lower than you would set privately, and you take whatever the annual fee schedule does to your codes. For most solos with a meaningful Medicare panel, the administrative simplicity and directory visibility outweigh that ceiling — but that is a judgment about your panel and your patients' ability to pay balances, not a rule that applies to every practice.

Non-participation: the trade you are actually making

Non-participation keeps you inside Medicare but changes the economics. You decide assignment claim by claim, and on a claim you do not assign you may bill the patient more than the approved amount — but only up to a federal ceiling, the limiting charge, and you are paid from a lower non-participating fee schedule. On an unassigned claim the patient pays you and Medicare reimburses the patient, not you.

That last mechanic is the one that surprises people. On unassigned claims you are collecting from the patient at the time of service and the Medicare payment flows to them, so your cash comes in faster but your front desk is doing more explaining and more collecting. You can still choose to accept assignment on any individual claim — for a patient who cannot pay the balance up front, for instance — which is the flexibility non-participation is really buying. It is a posture that rewards a practice whose patients can and will pay a balance and whose administrative appetite can absorb the per-claim handling.

Whether non-participation nets more than participation is arithmetic, not a slogan: the higher amount you can bill the patient has to be weighed against the reduced fee schedule and the added collection work. That comparison is the non-par math, and it turns on your specific codes and how reliably your patients pay a balance. Run it on your top few codes before you assume the balance-billing headroom is worth the reduced schedule and the extra collections, because for some code mixes the two effects nearly cancel.

Opting out: private contracts and no Medicare billing

Opting out is the most restrictive door and the slowest to reverse. You file an affidavit with your MAC — the regional contractor that processes Medicare claims for your state; CMS publishes which MAC that is 2Ref 2Centers for Medicare & Medicaid Services (2026).Medicare Administrative Contractors.That Medicare claims administration is regionalized across MACs and that CMS publishes which MAC serves each jurisdiction — the basis for the find-your-MAC step, since enrollment, the participation election, and the opt-out affidavit are handled by the reader's own regional contractor. — and you sign a private contract with each Medicare patient you treat. The patient agrees to pay your fee directly, and neither of you submits the claim to Medicare. The opt-out runs for a defined term.

What opting out buys is freedom from the fee schedule: your fee is whatever your private contract sets, not the Medicare-approved amount. What it costs is every patient for whom Medicare payment matters. A patient under a private contract cannot use their Medicare benefit for your services during the term, which narrows your Medicare panel to people willing and able to pay out of pocket. For a cash-pay or concierge practice that is the point; for a practice that depends on Medicare volume it is disqualifying.

The binding specifics — the exact affidavit, the current length of the term, and the private-contract language Medicare requires — are published by your MAC, and Novitas Solutions, for the states it covers, is one example of a contractor that posts its enrollment and opt-out steps 3Ref 3Novitas Solutions Medicare (2026).Novitas Solutions Medicare.That a Medicare Administrative Contractor (Novitas Solutions, for its jurisdictions) publishes the enrollment workflows, participation and opt-out steps, LCDs, and documentation and signature guidance that bind providers in its states — cited as one named example of where the jurisdiction-specific rules actually live, never as a national rule.. Read your own MAC's version before you commit, because the term is long enough that a wrong turn here is expensive to undo, and because the private contract has requirements of its own that a homemade agreement will not satisfy.

Before you choose: can you enroll, and as what?

The posture question only matters if your profession can enroll in Medicare at all, so settle that first. Medicare recognizes a defined list of provider types, and as of 2024 it added marriage and family therapists and mental health counselors to the behavioral health clinicians it will enroll and pay 4Ref 4Centers for Medicare & Medicaid Services (2025).Medicare and Mental Health Coverage.That Medicare covers behavioral health services and, since 2024, enrolls and pays marriage and family therapists and mental health counselors among its eligible provider types — the basis for the 'can you enroll, and as what' gate that precedes the posture choice.. A counselor who assumed Medicare was closed to them is working from an out-of-date rule, and the rules for psychologists and Medicare are their own established path.

A counselor who is newly eligible and a psychologist with a long-settled path still share the next trap: enrollment is not the same as credentialing or contracting, three steps people routinely collapse into one. Credentialing, enrollment, and contracting each answer a different question — whether your qualifications are verified, whether Medicare will pay you, and what a commercial plan's contract says — and the distinctions matter because you can be finished with one and nowhere on another. Enrolling yourself in Medicare runs through the 855i, the enrollment application for an individual provider, or its online equivalent in the enrollment system.

Timing is the part solos underestimate. Medicare's enrollment rules include a retrospective billing window tied to your effective date, which governs how far back you can bill once you are enrolled — so a gap between seeing your first Medicare patient and finishing enrollment is not automatically lost revenue, but it is not open-ended either. Start the enrollment before you need it, because the effective date, not the day you opened your doors, is what your claims are measured against.

How the choice touches MIPS and your Part B payments

Your Medicare posture also decides whether you are exposed to MIPS, the Merit-based Incentive Payment System. MIPS scores eligible clinicians on quality, cost, improvement activities, and interoperability, and then adjusts their Medicare Part B payment up or down based on the score 5Ref 5Centers for Medicare & Medicaid Services (2026).MIPS Overview.That MIPS scores eligible clinicians on quality, cost, improvement activities, and interoperability and adjusts their Part B payment, and that clinicians under the low-volume threshold are excluded — the basis for whether a participating solo is exposed to MIPS.. It applies to clinicians who bill Medicare, which makes it a consideration for participating and non-participating providers and a non-issue for a clinician who has opted out entirely.

Most solos, though, never reach the reporting requirement. Clinicians under the low-volume threshold are excluded from MIPS 5Ref 5Centers for Medicare & Medicaid Services (2026).MIPS Overview.That MIPS scores eligible clinicians on quality, cost, improvement activities, and interoperability and adjusts their Part B payment, and that clinicians under the low-volume threshold are excluded — the basis for whether a participating solo is exposed to MIPS., and a practice of one with a modest Medicare panel often falls below it. The practical move is to check whether you cross the threshold rather than assume either way, because the answer decides whether MIPS is a real cost of participating — reporting takes time and tooling that a solo has to supply personally — or something you can set aside without a second thought.

If you do cross it, fold the reporting burden into the participation decision honestly. MIPS is not a reason to opt out on its own, but it is a genuine administrative cost that lands on whoever is already doing the billing, the scheduling, and the notes — which, in a solo practice, is you. Knowing your status turns MIPS from a background worry into a line item you can plan for, and it is worth rechecking, because the threshold and the measures are revisited from year to year.

Where the binding numbers live — and the ABN

Every specific figure in this decision changes, so the durable skill is knowing where to look each one up. CMS publishes a public Physician Fee Schedule lookup: enter a code and your locality and it returns the Medicare-approved amount, the RVUs behind it, and the payment indicators for that code 1Ref 1Centers for Medicare & Medicaid Services (2026).Physician Fee Schedule Search.That CMS publishes a public Physician Fee Schedule lookup where a clinician enters a code and locality to read the Medicare-approved amount, its RVUs, and payment indicators — the method for finding the binding figures behind the participation decision instead of relying on a remembered number.. That is the anchor figure the whole participation calculation runs against, and it is the honest source for what a given service actually pays where you practice.

Two more lookups complete the picture. First, find your MAC: because claims administration is regionalized, the enrollment steps, the participation election, and the local coverage determinations that bind you are published by your own contractor, and CMS lists which MAC serves your state 2Ref 2Centers for Medicare & Medicaid Services (2026).Medicare Administrative Contractors.That Medicare claims administration is regionalized across MACs and that CMS publishes which MAC serves each jurisdiction — the basis for the find-your-MAC step, since enrollment, the participation election, and the opt-out affidavit are handled by the reader's own regional contractor.. Your MAC's site — Novitas, for its jurisdictions, is one example — is where the participation and opt-out mechanics, the LCDs, and the documentation and signature rules actually live 3Ref 3Novitas Solutions Medicare (2026).Novitas Solutions Medicare.That a Medicare Administrative Contractor (Novitas Solutions, for its jurisdictions) publishes the enrollment workflows, participation and opt-out steps, LCDs, and documentation and signature guidance that bind providers in its states — cited as one named example of where the jurisdiction-specific rules actually live, never as a national rule.. Second, the annual participation election has a window to change it; the timing of that December window is worth calendaring so a change lands in the year you intend rather than the one after.

Separately from the posture question is how you bill a Medicare patient for a service Medicare probably will not cover. That is the Advance Beneficiary Notice of Noncoverage, Form CMS-R-131, published under CMS's Beneficiary Notices Initiative, which the patient signs before the service so you can bill them if Medicare denies it 6Ref 6Centers for Medicare & Medicaid Services (2026).Beneficiary Notices Initiative (BNI).That the Advance Beneficiary Notice of Noncoverage (Form CMS-R-131), published under CMS's Beneficiary Notices Initiative, is required before billing a Medicare patient for a service Medicare is likely to deny — the mechanic for billing a patient directly, distinct from the balance-billing question the postures decide.. The ABN is about non-covered services; it is a different tool from the balance billing that non-participation allows on covered ones, and conflating the two is a common way to bill a patient you were not actually entitled to bill.

Common questions

Not necessarily — it is arithmetic. Non-participating providers are paid from a lower fee schedule but can bill the patient above the approved amount, up to the federal limiting charge. Whether that nets more than participation depends on your specific codes and how reliably patients pay a balance, plus the added collection work. Run the non-par math on your top codes rather than assuming the balance-billing headroom always wins.

Yes. Participation is an annual election, and there is a window each year to change it for the following year. Your MAC publishes the current window and the steps, and the timing is worth calendaring so the change takes effect when you want it. Switching between participating and non-participating is far easier than opting out and back in, which is governed by a longer, more formal term.

Yes, but only under a private contract in which the patient agrees to pay your fee directly and not to bill Medicare for your services during the opt-out term. That narrows your Medicare panel to patients willing and able to pay out of pocket. You file the opt-out affidavit with your MAC, and its current form, the required contract language, and the term length are published there.

They solve different problems. The limiting charge is the federal ceiling on what a non-participating provider can bill a patient above the approved amount on a covered service. An ABN, Form CMS-R-131, is what a patient signs before a service Medicare likely will not cover, so you can bill them if it is denied. One is about covered-service balance billing; the other is about non-covered services, and they are not interchangeable.

As of 2024, Medicare enrolls and pays mental health counselors and marriage and family therapists among its behavioral health provider types, so a profession that was previously closed out now has a path. Enrollment for an individual runs through the 855i application or its online equivalent. Confirm the current covered services and any telehealth rules for your provider type before you build a Medicare panel around it.

Use the CMS Physician Fee Schedule lookup. Enter the CPT or HCPCS code and your locality, and it returns the Medicare-approved amount, the RVUs, and the payment indicators for that code where you practice. That approved amount is the anchor every posture is measured against — the participating amount, the non-participating schedule, and the limiting charge all derive from it — so it is the first number to pull.

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References

1.Centers for Medicare & Medicaid Services (2026). Physician Fee Schedule Search. Centers for Medicare & Medicaid Services (CMS). link ✓That CMS publishes a public Physician Fee Schedule lookup where a clinician enters a code and locality to read the Medicare-approved amount, its RVUs, and payment indicators — the method for finding the binding figures behind the participation decision instead of relying on a remembered number.
2.Centers for Medicare & Medicaid Services (2026). Medicare Administrative Contractors. Centers for Medicare & Medicaid Services (CMS). link ✓That Medicare claims administration is regionalized across MACs and that CMS publishes which MAC serves each jurisdiction — the basis for the find-your-MAC step, since enrollment, the participation election, and the opt-out affidavit are handled by the reader's own regional contractor.
3.Novitas Solutions Medicare (2026). Novitas Solutions Medicare. Medicare Administrative Contractor portal. link ✓That a Medicare Administrative Contractor (Novitas Solutions, for its jurisdictions) publishes the enrollment workflows, participation and opt-out steps, LCDs, and documentation and signature guidance that bind providers in its states — cited as one named example of where the jurisdiction-specific rules actually live, never as a national rule.
4.Centers for Medicare & Medicaid Services (2025). Medicare and Mental Health Coverage. CMS Medicare Learning Network (MLN1986542). link ✓That Medicare covers behavioral health services and, since 2024, enrolls and pays marriage and family therapists and mental health counselors among its eligible provider types — the basis for the 'can you enroll, and as what' gate that precedes the posture choice.
5.Centers for Medicare & Medicaid Services (2026). MIPS Overview. CMS Quality Payment Program. link ✓That MIPS scores eligible clinicians on quality, cost, improvement activities, and interoperability and adjusts their Part B payment, and that clinicians under the low-volume threshold are excluded — the basis for whether a participating solo is exposed to MIPS.
6.Centers for Medicare & Medicaid Services (2026). Beneficiary Notices Initiative (BNI). Centers for Medicare & Medicaid Services (CMS). link ✓That the Advance Beneficiary Notice of Noncoverage (Form CMS-R-131), published under CMS's Beneficiary Notices Initiative, is required before billing a Medicare patient for a service Medicare is likely to deny — the mechanic for billing a patient directly, distinct from the balance-billing question the postures decide.

https://www.gale.care/for-providers/mc-par-vs-nonpar-optout · 6 sources. Competitor details are cited to dated public sources and maintained as they change; figures are estimates, not commitments. Synthetic demonstration.

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