> ## Documentation Index > Fetch the complete documentation index at: https://mso.getlemma.com/llms.txt > Use this file to discover all available pages before exploring further. # Enroll in Medicare (PECOS) > CMS-855B for the group, CMS-855I for the clinician, CMS-588 for EFT, reassignment of benefits, PTANs, ownership disclosure, and revalidation. Medicare enrollment is submitted through **PECOS** (the Provider Enrollment, Chain, and Ownership System) and processed by your regional **Medicare Administrative Contractor (MAC)**. A group needs the entity enrolled, each clinician enrolled, and each clinician's benefits reassigned to the group. ## Prerequisites * The PC formed, with EIN and CP 575 * Type 2 NPI for the PC; Type 1 for each clinician * The PC's bank account open (for CMS-588) * Practice location secured — a site visit is possible for some provider types * Ownership and managing control information assembled ## The forms | Form | Purpose | Filed by | | ------------ | ----------------------------------------------------------------- | -------------- | | **CMS-855B** | Enroll the group / clinic as a supplier | The PC | | **CMS-855I** | Enroll an individual physician or non-physician practitioner | Each clinician | | **CMS-855R** | Reassign benefits from the individual to the group | Both | | **CMS-588** | EFT authorization | The PC | | **CMS-460** | Participating provider agreement (optional but usually desirable) | The PC | Nearly all of this can be filed electronically in PECOS, which is faster and easier to track than paper. ## Steps Through CMS I\&A. The authorized official for the PC will need an account, and staff can be granted delegated access. Requires: legal business name matching the CP 575, EIN, Type 2 NPI, practice locations, correspondence address, authorized and delegated officials, and **ownership and managing control disclosure**. The 855B requires disclosure of persons and organizations with ownership or **managing control** interests. In an MSO-PC structure the honest answer for ownership is the clinician-owner, but "managing control" is broader than equity, and an MSO exercising significant management authority may need to be disclosed. This is a question for counsel, not a form to guess at. Under-disclosure is a misrepresentation; over-disclosure may raise questions you'd rather answer proactively than reactively. Get it right the first time. Individual enrollment. A clinician already enrolled elsewhere still needs to be associated with your group. This is what directs Medicare payment for the clinician's services to the **group's** Tax ID rather than the individual's. Without it, the group cannot bill for that clinician's services. Bank account details for the **PC's** operating account, with a voided check or bank letter. **The account must be the PC's**, not the MSO's. Medicare pays the enrolled supplier. See [Why MSO-PC banking is different](/concepts/banking/why-healthcare-banking-is-different). A **participating** provider accepts assignment on all Medicare claims. Non-participating providers may accept assignment case-by-case but are subject to the limiting charge and receive a reduced fee schedule amount. Most groups participate. On approval you receive a **Provider Transaction Access Number (PTAN)**, a MAC-assigned identifier distinct from the NPI. You need it for MAC portal access, claim status inquiries, and appeals. Record group and individual PTANs in your enrollment grid. Separate from the 855 enrollment. See [Set up EDI, ERA, and EFT](/guides/enrollment/set-up-edi-era-eft). Most providers revalidate **every five years**; DMEPOS suppliers every three. **Revalidation notices go to the correspondence address in PECOS.** If nobody monitors it, the first you'll hear is when billing privileges are deactivated. Confirm the address is one a human reads, and check your due date directly in the [Medicare Revalidation Lookup Tool](https://data.cms.gov/tools/medicare-revalidation-list). ## Timeline **Typically 60–120 days**, sometimes longer. Site visits, ownership questions, and incomplete applications extend it. Medicare has its own rules on retrospective billing for physician and non-physician practitioner enrollment, allowing billing for a limited period before the effective date in defined circumstances. Confirm the **current** CMS policy rather than relying on what a colleague did in a prior year. ## Opt-out A physician who has **opted out** of Medicare has private contracts with beneficiaries and does not bill Medicare at all. Relevant because: * An opted-out clinician cannot reassign benefits to your group * Opt-out is per-physician and runs for a defined period * It is more common in some specialties, notably psychiatry Check opt-out status during [clinician vetting](/guides/formation/vet-a-friendly-clinician), not after you've built the model. ## Verify it worked * [ ] 855B approved; group PTAN recorded * [ ] 855I approved for each clinician; individual PTANs recorded * [ ] 855R reassignment approved for each clinician * [ ] 588 EFT confirmed, depositing to the **PC's** account * [ ] Participating status decided and filed * [ ] Effective dates recorded in the enrollment grid * [ ] PECOS correspondence address monitored by a named person * [ ] Revalidation date calendared with a 90-day lead * [ ] ERA delivery configured ## Common failure modes | Failure | Consequence | | ---------------------------------------------------- | --------------------------------------------------- | | Legal name mismatch with IRS records | Application rejected | | Ownership and managing control disclosure guessed at | Misrepresentation risk | | 855R never filed | The group cannot bill for that clinician | | EFT pointed at the MSO's account | Compliance problem plus a re-enrollment cycle | | PECOS correspondence address unmonitored | Missed revalidation; deactivated billing privileges | | Missed revalidation | Deactivation; claims stop | | Assuming ERA is included in 855 enrollment | Payments arrive with no electronic remittance | ## Related topics - [Enroll in state Medicaid](/guides/enrollment/enroll-in-medicaid.md) - [Set up EDI, ERA, and EFT with each payer](/guides/enrollment/set-up-edi-era-eft.md) - [Track licenses, revalidations, and expirables](/guides/enrollment/maintain-revalidations.md) - [The US payer landscape](/concepts/payments/the-payer-landscape.md) - [Medicare (fee-for-service)](/reference/payers/profiles/medicare.md) - [Payer enrollment & submission links](/reference/payers/enrollment-links.md)