How to Apply for an EIN by Fax (Form SS-4 Guide for 2026)

Forming a United States entity—such as a Delaware or Wyoming LLC—is straightforward for international entrepreneurs. However, opening a US business bank account (like Mercury, Relay, or Brex), processing customer payments via Stripe, and establishing vendor relationships requires an Employer Identification Number (EIN) issued by the Internal Revenue Service (IRS).

If you do not possess a US Social Security Number (SSN) or Individual Taxpayer Identification Number (ITIN), you cannot use the instant IRS online application portal. For international founders, submitting Form SS-4 by fax to the IRS Fax-TIN unit is the primary official path.

This guide outlines the complete process for completing Form SS-4, verified fax routing numbers, and options for receiving your official IRS confirmation letter.

Why You Must Apply by Fax: The SSN/ITIN Constraint

The IRS operates an instant online EIN tool, but it enforces a strict gateway restriction: the individual listed as the "Responsible Party" must enter a valid 9-digit US SSN or ITIN.

+-------------------------------------------------------------+
|               HOW TO APPLY FOR AN EIN IN 2026               |
+-------------------------------------------------------------+
| US Resident with SSN/ITIN      --> Instant Online Tool      |
| Non-US Resident (No SSN/ITIN)  --> Form SS-4 via Fax / Mail |
| International Entity           --> Form SS-4 via Fax / Mail |
+-------------------------------------------------------------+

When a foreign founder without a US tax identification number attempts to use the online portal, the system blocks the application at the responsible party step. The only authorized filing methods remaining are:

1. Mail: Slower option, typically taking 4 to 8 weeks plus international transit time.
2. Fax: Primary recommended option, officially processed by the IRS Fax-TIN unit within approximately 4 business days to several weeks.

Verified IRS Fax Numbers for Form SS-4

The IRS routes Form SS-4 applications based on entity location and where the transmission originates. Use only the verified numbers below:

Source: IRS Where to File Taxes for Form SS-4. Verify numbers on IRS.gov before sending.

For a full directory of federal tax intake endpoints, see our IRS Fax Numbers Directory 2026.

Step-by-Step: Completing Form SS-4 for Foreign Founders

Completing Form SS-4 accurately is critical. A single missing field or formatting mistake will cause the IRS to reject the application or leave it unassigned.

+-------------------------------------------------------------+
|               FORM SS-4 CRITICAL FIELDS CHECKLIST           |
+-------------------------------------------------------------+
| Line 1   --> Exact legal entity name from Certificate       |
| Line 4   --> Mailing address (can be international)         |
| Line 6   --> State/County where LLC was registered          |
| Line 7a  --> Full legal name of Responsible Party (Owner)   |
| Line 7b  --> Write "Foreign" (do not leave blank)           |
| Line 8a  --> Check "Yes" if LLC                             |
| Line 9a  --> Check entity structure (e.g., Single-Member)   |
| Line 10  --> Check "Started new business" & state activity  |
| Line 18  --> Provide return fax number for IRS reply        |
+-------------------------------------------------------------+

Line 1: Legal Name of Entity

Enter the exact name of your business as registered with your state's Secretary of State (e.g., "Acme Software Solutions LLC"). Do not abbreviate or alter punctuation.

Line 4a–4b: Mailing Address

Enter the address where you want to receive tax notices. This can be your US registered agent address, a US virtual mailbox, or your international business address.

Line 5a–5b: Physical Address

If your business has a physical address different from the mailing address, enter it here. For international founders without a physical US office, this can be your operational headquarters abroad.

Line 7a: Name of Responsible Party

Enter the full legal name of the individual who controls, manages, or directs the entity (typically the founder or managing member). The IRS requires this to be an individual human being, not another holding company.

Line 7b: SSN, ITIN, or EIN

If the responsible party does not have a US Social Security Number or ITIN, write "Foreign" in box 7b.

Critical Warning: Do not leave box 7b blank. Leaving this box blank is the leading cause of immediate processing rejection.

Line 8a–8c: Limited Liability Company (LLC) Information

• Line 8a: Check "Yes" if your entity is an LLC.
• Line 8b: Enter the number of LLC members (owners). If you are the sole owner, enter
  .
• Line 8c: If you entered
  on Line 8b, check "Yes" if the LLC was organized in the US.

Line 9a: Type of Entity

• If you are a single-member LLC, check "Other" and write "Disregarded Entity - Single Member LLC".
• If you are a multi-member LLC, check "Partnership".
• If you formed a US Corporation, check "Corporation" and specify the form number (e.g., "1120").

Line 10: Reason for Applying

Check the appropriate box. Most international founders check "Started new business" and specify the core business activity (e.g., "SaaS software development and digital subscriptions").

Line 18: Have You Ever Applied for an EIN Before?

Check "No" unless this specific entity previously received an EIN.

Signature Block

The responsible party listed on Line 7a must sign and date the bottom of the form.

• Print your name clearly.
• Provide a valid contact phone number with country code.
• Include your return fax number: The IRS requires a return fax number to transmit your EIN confirmation notice back to you.

How the IRS Delivers Your EIN

When the IRS processes your faxed Form SS-4, an agent inputs the data into the Business Master File (BMF) database.

Once the EIN is generated:

1. The IRS creates the official confirmation document (Notice CP 575 or 147C Letter).
2. The agent places the confirmation sheet on their outbound fax terminal.
3. The IRS system faxes the confirmation directly to the return fax number provided on your application.

The Inbound Fax Problem for International Founders

Most founders outside the United States do not possess an active US fax machine or inbound telecom line configured to receive international faxes.

If the IRS attempts to fax your confirmation letter to an invalid or unresponsive number:

• The transmission fails.
• The IRS will not email the result.
• The IRS will default to mailing a physical letter via standard international post, which can take 4 to 8 weeks to arrive.

Comparison: Filing Options and Pricing

When choosing how to obtain your EIN by fax, you have three primary approaches:

Why SingleFax EIN by Fax ($9.99) Is the Preferred Path

With SingleFax EIN by Fax, you do not need to wrestle with IRS form formatting or maintain a dedicated telecom line:

1. Step-by-Step Form Builder: Answer straightforward questions online. Our system populates a fully compliant Form SS-4 PDF with verified "Foreign" entity notations.
2. Automated IRS Routing: The platform automatically routes and transmits the document to the correct IRS Fax-TIN unit (
   ,
   , or
   ).
3. 90-Day Dedicated Return Fax Line: We allocate a dedicated US inbound number to your application. When the IRS agent faxes the CP 575 confirmation notice back, our system intercepts the fax.
4. Instant PDF Email Delivery: As soon as the IRS confirmation arrives, we convert it into a high-resolution PDF and email it directly to your inbox.

Get started now at SingleFax Get EIN for $9.99.

Common Form SS-4 Mistakes to Avoid

1. Leaving Line 7b Blank: If you have no SSN/ITIN, you must write "Foreign". Blank fields cause automated clerk rejections.
2. Name Mismatch: The business name on Line 1 must match the Articles of Organization / Certificate of Formation issued by your state exactly.
3. Listing an Entity as Responsible Party: Line 7a must be an individual human being (owner, partner, director). Do not list a parent LLC or holding corporation.
4. Illegible Handwriting: When completing forms manually, scan at high contrast (300+ DPI). Typed or digitally generated PDFs are strongly preferred.
5. Missing Signature: The application must contain a handwritten physical signature or verified authorized signature.

Post-EIN Compliance: Next Steps

Once your EIN is assigned, remember your ongoing federal compliance obligations:

• Form 5472 and Pro Forma 1120: If you formed a US single-member LLC owned by a non-US person, you must file Form 5472 annually by April 15. Learn how to file Form 5472 by fax or use our Form 5472 filing service ($29.99).
• Form 7004 Extensions: If you need extra time to file Form 5472, read our guide on filing Form 7004 extensions by fax or submit your extension for $4.99 at File Form 7004.

Related Guides

• How to Fax the IRS in 2026 (Forms, Numbers, What You Can't Fax)
• IRS Fax Numbers Directory 2026: Verified Numbers for SS-4, 5472, and 7004
• How to File Form 5472 by Fax for Foreign-Owned US LLCs
• IRS and State Forms You Can Still Fax in 2026

Disclaimer: SingleFax provides document transmission and automated filing tools. SingleFax is not a law firm or CPA firm, and this content does not constitute legal, tax, or financial advice. Consult a licensed professional regarding your business structure and tax obligations.