The Short Answer
Form SS-4 is the one-page IRS application for an Employer Identification Number. It is free, you file it once per company, and you do not need employees to file it. If you have a U.S. Social Security number you can apply online and receive the EIN in minutes. If you are a non-U.S. founder without an SSN or ITIN, the online tool is closed to you — you file the same form by fax, mail or phone, and you write "Foreign" where the form asks for the responsible party's tax ID. Four entries on the form cause almost every rejection: the legal name, the responsible party's tax ID, the number of LLC members, and the entity type.
What ıs the SS-4 Form?
Form SS-4, titled Application for Employer Identification Number, is how the IRS gives your business its own federal tax identity. The EIN it produces is a nine-digit number written as XX-XXXXXXX, and it does for your company what a Social Security number does for a person: it identifies the entity on every tax filing, bank record and payment platform.
The name causes real confusion. "Employer" suggests payroll, but most companies that file an SS-4 never hire anyone. You need the number to open a business bank account, to get approved by Stripe, PayPal or Wise, to sell on Amazon or Etsy, to file federal returns, and to issue or receive tax documents.
It costs nothing. The IRS does not charge for an EIN, and there is no expedited paid tier. If you pay a fee somewhere, you are paying a provider to handle the filing, not the government. For the bigger picture on what the number does once you hold it, see our guide on what an EIN is and how to get it.
SS-4, EIN, CP 575 and 147C: What Is the Difference?
These four terms describe four different things, and mixing them up is the most common reason founders think a document is missing when it is not.
The SS-4 is the application — the form you fill in and send. The EIN is the number the IRS assigns in response. The CP 575 is the original confirmation notice the IRS sends once, containing that number. The 147C is a replacement verification letter you request when the CP 575 is lost, and it carries exactly the same weight for banks and processors.
So when a bank asks for "your EIN letter," it wants the CP 575 or a 147C — not your SS-4. Your own copy of the submitted SS-4 proves nothing to a third party, because anyone can fill in a form. If you cannot find your original notice, our walkthrough on requesting a 147C verification letter covers the process, and the guide on a lost EIN confirmation letter explains which route fits your situation. If you have simply forgotten the number itself rather than lost the paperwork, finding a lost EIN is a separate and much easier problem.
Who Needs to File Form SS-4
You file if your entity is a corporation or a partnership, if you will have employees, if you owe employment or excise taxes, if you administer an estate or trust, or if a bank or payment processor demands an EIN before it will open an account. That last reason covers the majority of new founders.
Single-member LLCs are the case people argue about. Because such an LLC is a disregarded entity for federal income tax, a U.S. owner can in theory report business income under their own Social Security number and skip the EIN. In practice this rarely survives contact with reality: banks and processors will not onboard a company without one, and a foreign-owned single-member LLC cannot file its mandatory Form 5472 package without one. Treat the EIN as non-optional.
Why the Online Application Is Closed to You
This is the wall most international founders hit, and the IRS website does not explain it prominently. The online EIN assistant requires the responsible party to have a valid SSN, ITIN or existing EIN, and it requires a U.S. principal place of business. If you are a founder in Istanbul, Lagos or São Paulo who has just formed a Delaware LLC, you satisfy neither condition, and the tool will reject you at the identity step or simply fail with a generic reference error.
That is not a bug and it is not something you can work around by entering a registered agent address. It means your route is the paper form. The obligation is identical, the resulting EIN is identical, and there is no disadvantage to the number itself — only to the waiting time.
Importantly, you do not need an ITIN first. Founders routinely spend months chasing an ITIN believing it is a prerequisite for the EIN. It is not. The two numbers serve different purposes and are obtained independently, which our comparison of EIN and ITIN sets out in detail.
The Four Lines That Cause Almost Every Problem
The form has eighteen numbered items, but four of them account for nearly all rejections and delays.
The legal name must match your certificate of formation exactly, including the "LLC" or "Inc." suffix and any punctuation. A shortened or prettified version is the single most frequent cause of a returned application.
The responsible party's tax ID must not be left blank. The responsible party is a real human being who controls the entity, never a holding company. If that person has no SSN or ITIN, write "Foreign." An empty field is processed as an incomplete application; the word "Foreign" is accepted.
The number of LLC members determines your default tax classification. Enter 1 for a single-member LLC and the true count for a multi-member one. Getting this wrong sets you up for the wrong return type later.
The entity type is where a single misplaced checkmark does the most damage. A single-member LLC that has not elected corporate treatment is a disregarded entity, not a corporation. Checking "Corporation" here creates a filing obligation that is genuinely tedious to unwind with the IRS.
How to Submit Form SS-4
There are four channels: the online assistant, fax, mail, and a dedicated telephone line for international applicants. Non-residents use the last three. Fax is generally the fastest of them, mail the slowest, and the phone line requires the responsible party to be available to answer questions live.
Whichever route you take, keep a signed copy of exactly what you submitted. If the IRS comes back with a query weeks later, that copy is your only reference point. Our guide for non-resident business owners covers the practical trade-offs between these channels.
The Mistakes That Delay an EIN
Filing before the state has approved your formation, so the legal name and formation date do not yet exist on the public record. Claiming employees you will not have. Filing a second application because the first one felt slow, which produces a duplicate EIN and a long correspondence to fix. Naming a third party designee without signing the authorization block, which causes that section to be silently ignored — a surprising number of founders never receive an EIN that was genuinely filed for exactly this reason.
What Happens After Your EIN Arrives
Save the confirmation notice in at least two places, ideally one physical and one cloud. The IRS issues the original once and will not reissue it; from that point on you are in 147C territory. Banks, payment processors and marketplaces will ask for it repeatedly over the life of the company.
Then check what the EIN switched on. For a foreign-owned single-member LLC it activates a reporting obligation whether or not the company earned anything, and missing that filing is far more expensive than any formation cost you have paid so far.
Frequently Asked Questions
Do I need an SSN to file Form SS-4?
No. Write "Foreign" for the responsible party's tax ID and file by fax, mail or phone instead of online.
Does Form SS-4 cost anything?
No. The IRS charges nothing for an EIN. Any fee is for a provider handling the paperwork.
Can I file before my LLC is approved?
You should not. Wait until the state approves the formation so the legal name and date match the public record.
What if I made a mistake on the form?
Do not submit a second application. Corrections are handled by written correspondence referencing the EIN already assigned.
Is Form SS-4 the same as an EIN letter?
No. The SS-4 is your application. The EIN letter is the IRS confirmation sent back to you.
Get Your EIN Without the Paperwork
One wrong checkbox on a one-page form can cost weeks, and for a founder outside the United States those weeks usually mean a frozen bank application and a launch that slips. Clemta prepares and files Form SS-4 for international founders, handles the foreign responsible party correctly, and delivers your EIN together with the confirmation letter you will be asked for again and again. Start your EIN application and get it right the first time.
This article is general information, not tax advice. Confirm your specific situation with a qualified tax professional before acting.
Özgür Kuşkonmaz
Head of Business Development at Clemta
