How to apply for an ITIN

An ITIN is a personal US tax number for people who have to file a US return but can’t get a Social Security number. You apply for it on Form W-7. And here’s the part most founders get wrong: you almost certainly don’t need one to run a US LLC. You need an EIN for that, which is a different number for a different thing.

So before you start chasing an ITIN, check whether you actually need it. Most non-resident LLC owners don’t.

When you actually need an ITIN

You need an ITIN when you personally have a US tax filing requirement and you’re not eligible for an SSN. In practice, for a non-resident founder, that means one of these is true:

• You have to file a Form 1040-NR because you earned US-source income or income effectively connected to a US trade or business.
• You’re claiming a tax treaty benefit that requires you to be identified to the IRS.
• You’re a partner in a US partnership that’s allocating you income and withholding tax.
• A US payer is withholding tax on a payment to you and you need to file to claim it back or report it.

Notice what’s not on that list: forming the company, getting its EIN, or opening a business bank account. Those don’t touch your personal tax number at all.

ITIN is not EIN — don’t mix them up

This is the single most common confusion, so it’s worth being blunt. An EIN is your company’s federal tax ID. A non-resident gets one with no SSN by filing Form SS-4, and it’s all you need to open a US business bank account and run a foreign-owned LLC. An ITIN is your number, for your personal filing.

If your LLC has no US trade or business and no effectively connected income, you may have no personal US return to file at all — in which case you never need an ITIN. Plenty of founders run a compliant US LLC for years without one.

What goes in a Form W-7 package

A complete application is three things together:

1. Form W-7 itself

   You state your reason for needing the ITIN (there’s a checkbox for each — non-resident filing a US return, treaty benefit, and so on), your foreign address, and your details exactly as they appear on your passport.

2. The tax return that creates the need

   Usually your Form 1040-NR. The W-7 rides on top of the return. The narrow exceptions (certain treaty and withholding cases) let you file W-7 alone with documentary proof of the exception instead of a return.

3. Proof of identity and foreign status

   You must prove both who you are and that you’re a foreigner. A valid passport is the one document that does both jobs by itself. Without a passport, you need two documents from the IRS-approved list (national ID, birth certificate, foreign driver’s license, visa, and similar).

The IRS will not accept plain photocopies. Your documents must be originals, or copies certified by the issuing agency. A notary public’s stamp is not enough on its own — this trips people up constantly.

The three routes — pick by how you feel about mailing your passport

Route 1 — mail original documents to the IRS. You send your actual passport (or certified copies from the issuer) to the IRS ITIN operation in Austin, Texas, with your W-7 and return. The IRS reviews it and mails the passport back. It works, it’s the cheapest, and it means being without your passport for weeks. For a lot of international founders, that alone rules it out.

Route 2 — use a Certifying Acceptance Agent (CAA). A CAA is authorized by the IRS to verify your passport and certify it for you, so the original never leaves your hands. They submit a certificate of accuracy with your W-7. This is the route most non-residents use, because many CAAs work with you remotely. It costs a fee, and it removes the two biggest pain points: the mail risk and the document rejections.

Route 3 — an IRS Taxpayer Assistance Center (TAC). Some IRS offices verify identity documents in person by appointment. Good if you happen to be in the US near one. Not practical for most people applying from abroad.

Timeline, and what comes back

Once the IRS has a complete package, expect 7 to 11 weeks for the ITIN. It runs longer during peak season (January through April) and when original documents have to be mailed back. The IRS sends you a notice (a CP565) with your assigned number, and processes the attached return using it.

If something’s missing — wrong document type, an incomplete W-7, no qualifying return — they mail back a rejection or a request for more, and the clock restarts. That’s exactly the failure mode a CAA helps you avoid.

Expiry and renewals

An ITIN isn’t forever. It expires if you don’t use it on a US tax return for three consecutive years. The IRS also retired older ITINs by middle digits on a rolling schedule in past years, so some long-dormant numbers are already dead.

If yours has lapsed and you need to file again, you renew it — same Form W-7, this time ticking the renewal box, with the same identity and foreign-status proof. Filing a return with an expired ITIN causes processing delays and can hold up any refund or treaty claim, so renew before you file, not after.

Where this fits in the bigger picture

For most non-resident founders the order is: form the LLC, get the EIN, open the bank account, operate. The ITIN only enters when you have a personal US filing — a 1040-NR or a treaty claim — and not a moment before. If you’re not sure whether your income is US-connected enough to trigger that filing, that’s the question to settle first, because it decides whether you need an ITIN at all.

This isn’t legal advice, and whether your income is effectively connected can be a genuinely close call. If you’re unsure, get a cross-border accountant to look at your specific facts before you file. We can run the W-7 and the return together when you do need them — and tell you honestly when you don’t.