Lost Your CP 575? Get an IRS 147C Letter for Credentialing
By George Ruan • October 7, 2026
Last reviewed: October 7, 2026.
If a payer wants your EIN letter and the original CP 575 is gone, request IRS Letter 147C. It confirms the same EIN and the legal name the IRS has on file, and payers that ask for tax documentation routinely list it next to the CP 575 as an acceptable substitute. You do not need a new EIN.
This guide is about producing proof of an EIN you already have. If the practice is actually moving to a different EIN, use our EIN-change checklist for insurance companies instead.
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Who Asks for the EIN Letter, and When
A signed W-9 is usually not enough on its own anymore. In our credentialing work, the IRS letter shows up as a required attachment at these points:
New group or solo applications to Blue Cross plans. Blue Cross Blue Shield of Illinois, for example, now requires a signed W-9 plus official IRS documentation assigning the billing TIN, such as Letter 147C or a CP 575 notice, on new-provider and add-provider requests.
Regence credentialing. Regence’s provider data team emails a request for “the 147C or CP 575 tax form for the clinic” and accepts it by email reply or by fax with their reference number on the cover sheet.
Medicaid group enrollment. Illinois Medicaid’s group application, for instance, asks for a W-9 and a CP 575 or 147C assignment letter. The IRS letter needs no signature.
Medicare enrollment and corrections. We upload a CP 575 or 147C as a supporting document with PECOS applications, including corrections Medicare sends back. CMS directs enrollment questions to your Medicare Administrative Contractor.
How to Get Letter 147C from the IRS
The IRS EIN page explains that a lost EIN confirmation can be replaced by calling the Business and Specialty Tax Line at 800-829-4933. In practice the request goes like this:
An owner, partner, or officer of the entity calls and passes the IRS identity questions. Have the EIN and the exact legal name ready.
Ask for Letter 147C and give the agent the fax number where it should go. One provider who had it faxed straight to us was told it could take up to 24 hours to arrive; it came through the next day.
If you want your biller or accountant to make the call, the IRS first needs your signed authorization, typically Form 8821. Portal access to your payer accounts does not give anyone authority to receive your IRS records.
Some businesses can also download a newer digital CP 575 from an IRS Business Tax Account. The IRS describes it on its CP 575 page as a substitute for the original notice or a 147C. Eligibility is limited, so the phone request remains the reliable route.
What Trips Practices Up
Sending a different IRS notice. Practices often attach whatever IRS mail they can find. An S-corporation election acceptance letter supports your tax status, not your EIN assignment. What reviewers want is the CP 575 (a variant such as CP 575G was accepted) or a 147C.
Two documents showing two EINs. When CAQH, NPPES, a W-9, and an old IRS notice disagree, we don’t pick one by guesswork. We ask for a fresh 147C for the EIN and legal name the owner wants to bill under, even if a CP 575 exists for one of them, and then make the W-9 and applications match it.
Name mismatches that are not real mismatches. IRS letters often truncate long names, and that is normal. A legal business name missing its “LLC” in NPPES is a real mismatch, though: we have seen Medicare return an application over exactly that.
Sending the letter to the wrong desk. A tax letter attaches to a specific request. When we sent one in support of a CAQH notification for a clinician who was already credentialed, Regence replied that adding a provider to a clinic goes through its Provider Information Update Form instead. Answer the request that asked for it, with its reference number.
Keep one clean copy. Save the full, unaltered letter in the practice’s secure records once it arrives. The same document will be requested again for the next payer, the next Medicare change, and Medicaid revalidation.
Bomi keeps the verified EIN letter on the practice record and reuses it across applications, so an owner usually only has to call the IRS once. See our credentialing service for how that works.
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Frequently Asked Questions
Is a 147C the same as a CP 575?
No. The CP 575 is the notice the IRS mails once when it assigns an EIN. Letter 147C is a verification letter you can request later. Both show the EIN and IRS legal name, which is why payers list them as interchangeable.
Can my biller request the 147C for me?
Yes, but only after you sign an IRS authorization such as Form 8821 naming them. Without it, the IRS will only speak with an owner or officer of the business.
Do I need a new EIN if I lost the letter?
No. Losing the paperwork does not change the number. Applying for a second EIN would create a new identity that no longer matches your existing contracts and claims.
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Founded by George Ruan, Dax Earl, and Andrey Goder, Bomi helps independent therapists and group practices with insurance billing, credentialing, and payer follow-up. Bomi grew out of Dax’s experience helping his mother with her therapy practice, with a clear purpose: reduce the administrative burden of insurance while keeping practice owners in control.
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