An EIN — Employer Identification Number — is the nine-digit tax identifier the IRS issues to US business entities. You need it to:
- Open a US business bank account at Mercury, Wise, Brex, Relay, Payoneer, or any US-chartered bank
- File Form 5472 (your legal name on the 5472 must match the EIN letter character-for-character)
- Hire a US contractor and file 1099-NEC
- Register for most state-level accounts in Delaware, Wyoming, and the other common formation states
For US-resident applicants with an SSN or ITIN, applying is straightforward: the IRS online form takes about 15 minutes and the EIN is issued immediately. For non-US founders without an SSN or ITIN, the picture is different. This guide walks through what actually works in 2026.
The three ways to apply
1. By fax using Form SS-4 (recommended for non-US applicants)
This is the path that works consistently for international founders. You fill in Form SS-4, fax it to the IRS, and typically receive the CP 575 letter by return fax within 4–8 weeks (though in busy IRS periods we have seen 10–12 weeks).
IRS fax number for international applicants (SS-4): +1-855-215-1627 — but confirm against the current IRS SS-4 instructions before you dial. The IRS has rotated this number before.
2. By mail using Form SS-4
The same form, but mailed to the IRS international service centre. Not recommended — the IRS does not acknowledge receipt until it issues the EIN, which can take 3–4 months by mail. Fax is strictly faster.
3. By phone (US-resident callers only, in practice)
The IRS Business and Specialty Tax Line accepts SS-4 applications by phone and issues the EIN on the call. In theory this is available to international callers. In practice:
- The international line (+1-267-941-1099) regularly has multi-hour wait times.
- The IRS agent on the call will walk through the SS-4 verbally. If any field is unclear, the application often gets rejected and you are told to fax a corrected form anyway.
- You cannot apply by phone if you do not have an SSN or ITIN; the IRS flags the application for routing to the SS-4 queue.
Pragmatic recommendation: skip the phone route. Fax works.
Filling in Form SS-4
The SS-4 is a one-page form with specific traps for international applicants.
Line 1 — Legal name
The exact legal name of your US entity. For an LLC, this should match the name on your certificate of formation from the state (Delaware, Wyoming, etc.). Any mismatch here will become a problem the moment you try to file 5472, because the 5472 wants the IRS record of the name, which comes from this field.
Lines 2 and 3 — Trade name and executor/administrator
Usually left blank for a founder-run LLC.
Line 4a and 4b — Mailing address
This is where the CP 575 (your EIN confirmation letter) will be sent. Options:
- Your US registered agent’s address (strongly recommended if your RA accepts mail-forwarding)
- A commercial mail-forwarding service in the US (Earth Class Mail, iPostal1, etc.)
- Your personal address outside the US (works, but delivery is slow and the IRS mailbox integration is unreliable)
Note: you can specify “fax” as the delivery method in a cover letter when you fax the SS-4, and the IRS will fax back the CP 575. This is the fastest option for non-US applicants.
Line 5a and 5b — Street address (if different)
Only if you have a physical street address different from the mailing address. Usually the same as 4a/4b for international founders.
Line 6 — County and state of principal business
For a Delaware LLC: “New Castle” county, Delaware. For Wyoming: usually “Laramie” county. The state matches the state of formation.
Lines 7a and 7b — Responsible party
The individual who ultimately owns or controls the entity. For a single-member LLC, this is you. Enter your name and your foreign tax identification number (UK UTR, Indian PAN, UAE TRN, etc.) in line 7b. If you have no foreign TIN, enter “Foreign — no ITIN” and attach a short statement explaining.
The IRS used to accept the entity type’s EIN in this field for a nested-entity application. In 2018 the IRS tightened the rule — the responsible party must now be a natural person with a tax identifier (or a documented explanation of why no identifier exists).
Line 8a and 8b — LLC classification
Check “Yes” to “Is this application for a limited liability company?”, then enter “1” for a single-member LLC or “2+” for a multi-member LLC.
Line 9a — Entity type
For a single-member LLC with a non-US owner, the default is “Other” with the explanation “Foreign-owned U.S. disregarded entity”. For a multi-member LLC, “Partnership” is the default. For a C-corp (or an LLC that will elect C-corp taxation), “Corporation (form number 1120)”.
Line 10 — Reason for applying
For a new entity: “Started new business”. For a bank-account-required application: “Banking purpose”.
Line 11 — Date business started
The date on your certificate of formation from the state.
Line 12 — Closing month of accounting year
For most founders, December (calendar year). Only pick a non-December closing month if you have a specific reason.
Lines 13 and 14 — Employees
Usually zero for a new founder-only LLC.
Line 15 — First date wages were paid
Leave blank for a founder-only LLC with no employees.
Line 16 — Principal business activity
Short description of what the LLC does. “Software development”, “Marketing services”, “E-commerce — physical products”, etc. The IRS does not grade this; a short honest description is fine.
Lines 17 and 18 — Products or services
A one-line description. “SaaS subscription for X” or “Freelance design services”.
Signature
The responsible party signs. For a non-US applicant, this is you.
The fax process end-to-end
- Fill in Form SS-4. Save it as a PDF.
- Prepare a one-page cover letter requesting fax-back delivery of the CP 575 to a specified fax number. Many online fax services (SRFax, HelloFax, Vonage) will accept inbound faxes to a dedicated number you control.
- Fax both pages to the IRS international SS-4 fax number.
- Wait. In busy IRS seasons (Jan–April, Sept–Oct), expect the full 8-week window. Off-peak, 4–5 weeks is more typical.
- The IRS faxes back the CP 575. Save it. Save it again. The CP 575 is the single most-requested document in your filing stack, and the IRS does not re-issue it — if you lose it, you can only ever get a 147C replacement letter, which carries the same information under a different letter code but is a different document.
Common mistakes
Rushing to apply before the LLC is actually formed
The state (Delaware, Wyoming) issues the certificate of formation. Only then does the entity exist. Applying for an EIN before formation produces a rejection — the IRS cannot assign a number to an entity that does not yet exist.
Using an EIN application service that invents a US SSN
Several questionable services online offer to “obtain your EIN quickly” by filing an SS-4 on your behalf using a US-resident SSN as the responsible party. This is fraud. The IRS has specifically called out this practice and rejects applications where the responsible party is clearly not the actual owner.
Picking a nested-entity structure to avoid the responsible-party rule
Some founders try to form a UAE free-zone entity as the owner of the US LLC and list the UAE entity in the responsible-party field. The IRS now requires a natural person in the responsible-party field, with their individual tax identifier. The nested structure can still work, but on the SS-4 you still list yourself as the natural-person responsible party.
Not keeping the CP 575 in a known location
Of every document in a non-US founder’s filing stack, the CP 575 is the one most often lost. The IRS will not re-issue it; a 147C is the replacement, which takes another IRS phone call to arrange. Save the PDF in at least two cloud services and in a password manager vault.
What BorderFile does and does not do
We do not apply for your EIN. The IRS requires the signature of the responsible party, which is you.
We do accept your CP 575 or 147C during intake and validate the legal name and EIN against your 5472 draft. If the IRS record and the state record differ, we flag that before it becomes a filing problem.
If you are preparing to apply, send us a draft SS-4 at support@borderfile.io and we’ll review it against the common mistakes before you fax.
Not tax advice; see the disclaimer.