How to Add a Provider to Your Group: Medicare, Medicaid and Every Payer
New hire, new location, new tax ID, an acquisition or a new billing company: what changes, which filing each payer wants, and what to do in what order.
Adding a provider to an existing group is two different steps with every payer: the provider's own credentialing or enrollment with that payer, if they are not already in network, and the link that puts the provider on the group's tax ID and contract. Each payer has its own form or portal for each step, and none of them sees the others' changes. For Medicare, the link is a reassignment of benefits on the CMS-855I, section 4F, filed in PECOS. For commercial plans it is that plan's add-a-provider route: Onboard Pro at UnitedHealthcare, a per-provider application at Aetna, Availity at Florida Blue.
The same mechanics apply when you open a second location, move to a new tax ID or buy a practice, so this page covers all of them. If you are setting up a brand-new practice from scratch, the full sequence is in how to get credentialed with insurance companies.
Last updated October 23, 2026. Reviewed by Jacob Greenberg, ClaimCarePro.
Which practice change you have, and what it changes
Seven situations, what actually changes, and the filing each one needs. Sources are in the sections below, all read October 23, 2026.
| Situation | What changes | Which filing |
|---|---|---|
| New hire, already in network with the payer elsewhere | Only the link to your tax ID and contract. The provider’s own credentialing file usually stands | Medicare: CMS-855I section 4F reassignment to your group (and end the old one). Commercial: each payer’s add-to-group route (Onboard Pro, Availity, roster). CAQH: authorize your payers, add your location |
| New hire, not yet in network with the payer | Both steps: the provider’s own credentialing or enrollment, then the link to your group | Medicare: initial CMS-855I with the reassignment added. Commercial: a full application per payer. See how to get credentialed |
| New or second location, same tax ID | Service address on every record; a 30-day Medicare clock | Medicare: CMS-855B location change for the group and the reassignment's location for each provider. Medicaid: written report within 30 days. Commercial and CAQH: add the location |
| New tax ID or new LLC | The entity on the contract. Some payers treat it as an update, Medicare treats a new entity as a new group | Medicare: new CMS-855B and new reassignments for the new entity. Aetna: Update Tax ID tile, same state. Florida Medicaid: report with proof. Others: ask first |
| Buying a practice (change of ownership) | Who owns the enrollments and contracts, and who gets paid | Medicare: ownership change reported within 30 days; a new tax ID generally means a new enrollment by the new owner (42 CFR 424.550(c)). Florida Medicaid: written notice 60 days in advance. Commercial: each payer decides whether the contract follows |
| A provider leaves | The link ends; the provider’s own enrollment stays with them | End the reassignment and every payer roster entry. See leaving a group practice |
| Switching billing or credentialing company | Who files and follows up. Not an enrollment change | No new enrollment. ERA/EFT and clearinghouse routing, Florida Medicaid trading partner (Form 5000-1062), CAQH access. See switching credentialing companies |
The last row matters more than it looks. A new billing or credentialing company changes who does the work, not the provider's enrollment: the reassignments, contracts and effective dates stay where they are. What moves is payment routing and access, and that has its own checklist on switching credentialing companies.
Medicare reassignment of benefits: adding a provider to a group in PECOS
The forms are explained on our Medicare enrollment page; this is what adding a provider takes.
To add a provider to a Medicare group, the provider reassigns their right to Medicare payment to the group on the CMS-855I, section 4F, usually filed in PECOS. The 855R was retired; reassignment is 855I section 4F. CMS's consolidated bulletin says MACs have returned filings on the old form since November 1, 2023 (CMS 855I bulletin).
The bulletin lays out the filing for a provider already enrolled in Medicare:
- Report a change to existing enrollment and choose "Reassignment of Benefit Information."
- In section 4F, check "Add," enter the effective date and name the group; section 4F3 lists the primary and secondary locations where the provider sees patients in person.
- The provider signs section 15B and the group's Authorized or Delegated Official signs section 15C. That pair of signatures is the authorization statement for reassignment of Medicare benefits.
A provider new to Medicare adds the same section 4F reassignment inside the initial application. Two conditions trip practices most. The group itself must already be enrolled, on the CMS-855B, or there is nothing to reassign to. And a provider moving from another group should end the old reassignment in the same motion; CMS lists ending one reassignment while keeping another as a standard change in PECOS (CMS: Manage your enrollment).
The 30-day and 90-day clocks
42 CFR 424.516(d) gives a group and its providers 30 days to report a change of ownership, an adverse legal action, or a change, addition or deletion of a practice location, and 90 days for all other changes (42 CFR 424.516). The clock that costs money is the effective date. Under 42 CFR 424.520(d) it is the later of the date an application that is later approved was filed, or the date the provider first furnished services at the new location (42 CFR 424.520). Medicare then allows billing up to 30 days before that date when circumstances precluded earlier enrollment (42 CFR 424.521). A reassignment filed six weeks after the start date leaves the early weeks outside that window.
Form detail, PTANs, the CMS-588 and CMS-460, and First Coast processing are on Medicare provider enrollment and what PECOS is.
How to add a provider to a group, payer by payer
What each payer publishes for adding a provider, and the timeline it states. Where a payer publishes nothing, the row says so.
| Payer | Route to add a provider | What the payer publishes on timing | Source |
|---|---|---|---|
| Medicare (First Coast in Florida) | CMS-855I section 4F "Add" in PECOS; group on CMS-855B. 30-day / 90-day reporting | Effective date = later of filing date or first service at the location; 30-day retro billing | CMS 855I bulletin |
| Florida Medicaid | Group Membership Authorization, AHCA Form 5000-1061, via FLMMIS; each managed-care plan separately. See the Florida credentialing guide | Changes reported within 30 days; no add-to-group timeline published | AHCA policy, Feb 2026 |
| Aetna | A separate application for each provider in the group; same-state tax ID change via Provider Onboarding Center > Existing Provider Resources > Update Tax ID | Published schedule for new participants: request 1–30 days, contracting 30–60, credentialing 60–90, final contract 90–120 | Join the network; Spring 2025 bulletin |
| UnitedHealthcare | Onboard Pro walks you through adding a new in-network provider under an existing group contract; roster and My Practice Profile by tax ID | “Generally takes up to 45 calendar days or more”; up to 60 days to load the contract; the UHC FAQ also says generally up to 14 calendar days | Join our network; Demographics page |
| Cigna / HealthSpring | Commercial: CAQH-based credentialing, no public add-to-group form. HealthSpring (Medicare Advantage): Provider Data Intake form adds practitioners to an existing participating group | Cigna: medical credentialing “typically 45 to 60 days”; directories and claim systems usually updated within 10 business days | Cigna; HealthSpring PDI |
| Humana | No national add-to-group form published; market-specific routes and the regional contracting contact | Medicare products, non-delegated group: network effective date 30 calendar days after all required documents are received (notice effective June 13, 2025) | Humana credentialing |
| Florida Blue (and other Blue plans) | Availity forms: Physician and Group Request to Participate, Update Provider Information, Panel Status Change Request | Not published for an added provider | Florida Blue forms |
| TRICARE East (Humana Military) | Adding a provider to an in-network practice runs through provider self-service; documents go to the TRICARE Community Liaison by secure message | Not published for an added provider | Humana Military FAQ |
Aetna: "aetna add provider to group" leads to Aetna's join-the-network page, which says a separate application is needed for each physician or provider in a group (Aetna). Its Spring 2025 bulletin lists what must be true in CAQH first: the profile in "Re-attestation" or "Initial Application Complete" status, Aetna listed as an authorized plan, current malpractice information, and every active service location in the state listed. Aetna Credentialing Customer Service is 1-800-353-1232 for a request past its published timeline (Aetna bulletin). More on Aetna credentialing.
UnitedHealthcare: joining a practice that already has a UHC agreement still requires onboarding before the provider sees patients as in network, and Onboard Pro handles it (UHC). If your group bills under more than one tax ID, UHC says updates must be made to all profiles (UHC demographics). See UnitedHealthcare and Optum credentialing.
Cigna, Humana, Florida Blue, TRICARE: Cigna's public page routes medical practitioners through CAQH-based credentialing; its Medicare Advantage brand, HealthSpring, launched a Provider Data Intake form in July 2026 that adds practitioners and locations to an existing participating group. Humana's Medicare notice is the one published effective-date rule for an added provider we found, and it starts the 30 days only when the last required document arrives. Florida Blue's forms run through Availity. Our Cigna, Humana, Blue Cross Blue Shield and TRICARE guides have the rest, and the full list is on the payer credentialing hub.
Florida Medicaid: linking a provider to your group
Short version; the Florida Medicaid guide has the full enrollment walk-through.
Florida Medicaid links a provider to a group through the Group Membership Authorization, AHCA Form 5000-1061, on the FLMMIS portal. AHCA's February 2026 enrollment policy (incorporated in Rule 59G-1.060) requires it when forming, joining or separating from a group, and uses the same form when a provider reassigns payment to an enrolled group. Ending the reassignment is a written request with the effective date, the group's Medicaid ID and the provider's Medicaid ID; the group can file it on the provider's behalf (AHCA policy, sections 2.6.1 and 5.6).
The state record is not the plan record. Each Medicaid managed-care plan adds the provider to the group on its own roster, so a provider linked in FLMMIS can still be missing at the plan. Enrollment detail is on Medicaid provider enrollment and the Florida provider credentialing guide.
Opening a second practice location
Same tax ID, same providers, new address: an update, but one with deadlines.
A second location under the same tax ID is usually an update to existing records, not a new credentialing file, but every record has to learn the new address before claims carry it. Medicare treats the addition of a practice location as a 30-day report (42 CFR 424.516(d)). For a group, First Coast reports the change on the CMS-855B (First Coast tutorial), and each provider's reassignment lists where they see patients in section 4F3. Florida Medicaid wants enrollment changes in writing within 30 days, and an in-state provider must have a Florida office where services are given (AHCA policy, sections 2.3 and 5).
For commercial payers and CAQH, work through the location one record at a time:
- Add the address to every provider's CAQH profile who will see patients there, and re-attest. Aetna checks that every active service location in the state is listed.
- Add the location with each plan: HealthSpring's intake form adds service locations, UHC uses its roster and My Practice Profile, Florida Blue uses Update Provider Information in Availity.
- Update the NPPES record if the practice location on the NPI changes. Federal rules give a provider 30 days to report changes to NPPES (45 CFR 162.410).
- Check the payer directory for the new address before you advertise it. A location a payer does not have on file is not covered just because the provider is.
New tax ID, same provider: changing entities or forming a new LLC
No payer treats a tax ID change as a formality, and they do not all treat it the same way.
When your practice moves to a new tax ID, the providers keep their own credentials, but every contract and enrollment tied to the old tax ID has to be moved, updated or replaced, and each payer decides which. Aetna says a same-state tax ID update runs through its Provider Onboarding Center (Existing Provider Resources, then Update Tax ID) and needs no new application (Aetna bulletin). Florida Medicaid requires a written report of a changed TIN with the previous identifier, the new one and proof from the issuing agency, and a provider re-enrolling under a different TIN must supply the old name, TIN and Medicaid ID (AHCA policy, sections 2.15.3 and 5.2).
Medicare enrolls a group as a legal entity. A new LLC is a new group, which means a new CMS-855B, a new reassignment from each provider, and the old entity's enrollment ended or reported. A legal business name change on the same tax ID is a different, smaller report that First Coast lists on its own (First Coast). Ask the MAC which applies before you file anything.
Before the switch date, build an old-to-new map:
- List every payer and product the old tax ID bills, with its provider IDs.
- For each, write down the transaction that payer says it needs: update or new application.
- Get a written effective date for the new tax ID from each payer.
- Keep billing under the old tax ID for any payer that has not confirmed the new one. Claims under a tax ID the payer does not have on file can deny.
Buying a practice: Medicare change of ownership and acquisitions
Enrollments and contracts do not transfer just because the practice did.
A Medicare billing number cannot be sold, and no one may use another's (42 CFR 424.550(a)). Physician groups are suppliers, and for suppliers 424.550(c) applies: a change of ownership or control is reported on the enrollment within 30 days, and a change of ownership that changes the tax ID generally requires the new owner to submit a new enrollment application. In practice the buyer is a new group on a new CMS-855B, with new reassignments from each provider (424.516(d) sets the same 30-day window). The "both owners file before the change completes" rule in 424.550(b) is for institutions with a part 489 provider agreement, such as hospitals.
Florida Medicaid requires a change of ownership reported in writing at least 60 days in advance, and its provider IDs do not transfer except for hospitals, intermediate care facilities and skilled nursing facilities (AHCA policy, section 5.4 and its provider-ID rules). Commercial contracts are with the legal entity, and whether a contract follows the sale is each payer's decision under that contract. Ask each payer before closing, not after.
Can the new provider see patients before they are linked?
Seeing patients is allowed; being paid in network for them is the question.
A new provider can see patients before every payer link is done, but each payer pays in network only from the effective date it sets. For Medicare, that date and the 30-day retro window come from 42 CFR 424.520(d) and 424.521(a), above. Humana's Medicare notice says members seen before the 30-day network effective date generally have claims paid at an out-of-network level (Humana). Billing the new provider's visits under a colleague's NPI is not a workaround. The full answer, payer by payer, is on billing before credentialing is complete.
How long does adding a provider to a group take?
Only what payers publish, dated. None of these are deadlines.
It depends on the payer, and few publish a figure for adding a provider rather than credentialing a new one. UnitedHealthcare says its process "generally takes up to 45 calendar days or more," with up to 60 days to load a contract, and its FAQ gives generally up to 14 calendar days. Cigna says medical credentialing typically takes 45 to 60 days. Aetna's schedule for new participants runs from 1 to 120 days across four stages. Humana's Medicare products use a network effective date 30 calendar days after all required documents arrive. A provider already in network with a payer usually needs only the link, which tends to move faster than fresh credentialing, but the payers do not publish a separate number for it, so we do not either. The comparison across payers is on how long credentialing takes.
The order of operations
What to do first, and what breaks when a step is skipped.
- Fix the data before any form. In our casework, files stall on bad data from the providers far more than on the payers: an old address, a lapsed malpractice certificate, a prior group's tax ID, an NPI record that disagrees with CAQH. One mismatch sends an application back.
- Confirm the group is enrolled with Medicare and Medicaid before the provider reassigns to it.
- File Medicare and Florida Medicaid inside their 30-day windows, ending any old reassignment at the same time.
- Bring CAQH current: new location, your payers authorized, profile re-attested. See CAQH explained.
- Submit to every commercial payer in parallel, one application or add request per provider per payer.
- Get each effective date in writing, then check the directory and run a first claim before scheduling the provider as in network.
The document list for steps 1 and 4 is our intake packet: what we need to start credentialing.
What we need from you
Group facts once, provider facts per provider.
- Group: group NPI, tax ID and W-9, legal business name, each payer contract or participation ID, every service location, and the PECOS and FLMMIS group IDs if you have them.
- Provider: individual NPI, CAQH ID with a current attestation, state license, DEA registration if they prescribe controlled substances, malpractice certificate, current payer IDs, and the start date and locations they will work.
- For a tax ID change or purchase: the new entity's IRS letter, the switch or closing date, and the old entity's payer list.
The full checklist, with the format each item comes in, is on what we need.
What ClaimCarePro does, and what it costs
Flat, published prices. Payer- or state-imposed fees pass through at cost.
We file every link and update in the order above, then follow up with each payer weekly and log the rep, the date and the reference number until the payer confirms the provider on your contract with an effective date. Adding a provider is $250 per payer application per provider. A new tax ID or new practice can take the new-practice bundle: $1,750 per provider for CAQH, Medicare, Medicaid and six commercial payers, and $1,400 for each additional provider on the same group and payers. Ongoing address and tax-ID updates are part of maintenance, $99 per provider per year. Everything is on provider credentialing services, with 30+ years combined experience behind it.
Adding a provider to your group: questions, answered
How do I add a provider to my group in PECOS?
Is there still a separate Medicare reassignment of benefits form?
What is the authorization statement for reassignment of Medicare benefits?
How soon do I have to tell Medicare about a new provider or location?
Can a new provider bill under the group before they are linked?
Does an already-credentialed provider need to be credentialed again to join my group?
Do I need new payer contracts if my practice changes its tax ID?
What happens to Medicare enrollment when a practice is bought?
How do I add a provider to my group with Florida Medicaid?
How much does it cost to add a provider to a group?
Sources
- CMS, Consolidated CMS-855I bulletin (855R discontinued; section 4F steps), read October 23, 2026
- CMS, Manage your enrollment and Enrollment applications, read October 23, 2026
- 42 CFR 424.516, 424.520, 424.521, 424.550 and 45 CFR 162.410 (Cornell LII), read October 23, 2026
- First Coast, Enrolling and reporting changes (June 26, 2026) and CMS-855B address-change tutorial
- AHCA, Florida Medicaid Provider Enrollment Policy (February 2026), incorporated in Rule 59G-1.060, F.A.C.
- Aetna, Join the network and Provider Education Bulletin, Spring 2025
- UnitedHealthcare, Join our network and Demographics, profiles and attestation
- Cigna, Credentialing and HealthSpring, Provider Data Intake form (July 16, 2026, updated September 10, 2026)
- Humana, Credentialing and CAQH
- Florida Blue, Provider forms
- Humana Military, Provider certification FAQ
Add your provider without losing billable weeks
$250 per payer application per provider. New tax ID or new practice: $1,750 per provider, $1,400 each additional.
Prefer to talk first? Call (844) 772-8902 or contact us.
Last updated October 23, 2026. Reviewed by Jacob Greenberg, ClaimCarePro.