ITIN vs EIN: Which One a Non-Resident Actually Needs

Two acronyms dominate the first week of setting up a US company from abroad, and they are routinely presented as a choice. They are not. An EIN identifies a company; an ITIN identifies a person. Asking which one you need is like asking whether you need a company registration number or a passport — the answer depends on which of you is being identified, and often the answer is that the company needs one and you need nothing. This guide sets out what each number is for, which one a non-resident LLC owner actually needs, and the specific situations that create a personal filing obligation and therefore an ITIN.

The distinction in one line

An EIN is a federal tax identification number for an entity. The IRS describes it as a federal tax ID for businesses, tax-exempt organisations and other entities, and lists the things that must have one: a partnership, a limited liability company, a corporation, a tax-exempt organisation, an estate, a trust, a retirement plan, a real estate mortgage investment conduit, a farmers' cooperative.

An ITIN is a tax processing number for an individual. Per Publication 1915, it is issued to certain resident and nonresident aliens, their spouses and their dependents who are not eligible for a Social Security Number but who have US tax filing or payment responsibilities.

The confusion is understandable because both are nine digits and both come from the IRS. But they answer different questions, they are obtained through different forms, and holding one tells you nothing about whether you need the other. Your LLC's EIN does not identify you. Your ITIN does not identify your LLC.

If you are forming a US LLC, you need an EIN

This part is not really a decision. The IRS lists a limited liability company among the entities that require an EIN to operate, so the number comes with the structure. You will also need it for anything practical: opening a business bank account, onboarding to a payment processor, and filing the annual Form 5472 that foreign-owned LLCs owe.

Beyond the entity list, the IRS says you need an EIN if you have employees, if you will pay employment, excise, or alcohol, tobacco and firearms taxes, or if you withhold taxes on income other than wages paid to a non-resident alien. It also notes that even where there is no federal tax need, you can still request one for banking or state tax purposes — which is the situation most dormant foreign-owned LLCs are in.

Two practical points the US-focused guides tend to skip. First, form the entity before you apply: the IRS instruction is to register the LLC, partnership or corporation with your state first, then apply for the EIN. Second, the EIN is free. The IRS issues it at no charge and says so on its own page. Formation services bundle EIN acquisition into their pricing, and what that price buys is handling the slower non-resident application route, not the number.

A responsible party who has no SSN or ITIN cannot use the IRS online application. That is the single fact behind most of the frustration non-residents report, and it does not mean you are ineligible — it means the online channel is closed to you and the alternative submission routes for international applicants apply instead. Our guide to getting an EIN as a non-US resident covers that process, and the 147C letter is how you retrieve the number later if you lose the original notice.

You need an ITIN only if you have to file

Here is the test that resolves most cases. An ITIN exists to let an individual meet a US tax obligation they already have. If you have no personal US filing requirement, an ITIN has nothing to do.

Publication 1915 gives the examples. A nonresident alien claiming the benefit of a reduced withholding rate under an income tax treaty. A nonresident alien not eligible for an SSN who is required to file a US federal income tax return, or who is filing only to claim a refund. A nonresident or resident alien electing to file a joint return with a spouse who is a US citizen or resident. A US resident alien under the substantial presence test who is not eligible for an SSN. A nonresident alien student, professor or researcher required to file.

Now apply that to the common case on this site. A non-resident alien owning a single-member LLC that is a disregarded entity, with no effectively connected income and no US-source income, generally has no US federal income tax filing requirement at all. No filing requirement means no ITIN requirement. The LLC still files its Form 5472 with a pro forma 1120 — but that filing uses the LLC's EIN, not a personal number.

Where the ITIN does become necessary is when the facts change: the LLC generates effectively connected income you must report on Form 1040-NR, you want to claim a treaty position on withholding, or you take US-source income personally. At that point the number stops being optional, because you cannot file a personal return without an identifying number in the SSN field.

What an ITIN is not

Publication 1915 is unusually direct on this, and it is worth quoting the limits because a whole industry sells around them. An ITIN:

1. does not authorise work in the US or provide eligibility for Social Security benefits or the Earned Income Tax Credit;
2. is not valid for identification outside the tax system; and
3. does not change immigration status.

ITINs are issued regardless of immigration status, precisely because both resident and nonresident aliens can have US tax responsibilities under the Internal Revenue Code. It is a compliance tool, not a status.

The number itself is formatted like an SSN — nine digits beginning with 9, with the fourth and fifth digits falling in defined ranges. When you file, you enter the ITIN in the space provided for the SSN on Form 1040, 1040-NR or 1040-X.

One sequencing rule catches people. If you have an SSN application pending, do not file Form W-7. You complete the W-7 only after the Social Security Administration notifies you that you are not eligible, and proof of that denial goes in with the application.

How to apply for each

The EIN is applied for on Form SS-4. Applicants with an SSN or ITIN as the responsible party can use the IRS online tool and receive the number immediately; everyone else uses the alternative channels available to international applicants. Form the entity with the state first. The number is free, does not expire, and is never reissued to a different entity. If you lose the confirmation, request Letter 147C or an entity transcript rather than applying again — applying twice creates two EINs for one entity and a cleanup problem.

The ITIN is applied for on Form W-7, and the requirement that surprises people is that the W-7 must be filed with a valid US federal tax return attached, unless you meet one of the published exceptions to return filing. This is the mechanical expression of the principle above: the ITIN exists to support a filing, so the IRS wants to see the filing. You can also apply through an Acceptance Agent. The IRS returns the ITIN in an assignment letter.

Then there is expiry, which is the ITIN's least-known feature. If your ITIN was not included on at least one US federal tax return for three consecutive tax years, it expires on 31 December of the third consecutive year and must be renewed before it can be used again. ITINs assigned before 2013 that were never renewed need a renewal application submitted with your return. An EIN has no equivalent — once issued, it stays yours.

The short answer for most readers

If you are a non-resident forming a US LLC to invoice clients, and the business has no US premises, no US employees and no US-source income: you need an EIN for the company and, in all likelihood, no ITIN for yourself. Get the EIN, keep the confirmation letter, and file the Form 5472 each year.

Revisit the question if any of these become true: the business generates effectively connected income, you want to rely on a treaty position to reduce withholding, you receive US-source income personally, or you spend enough time in the US to meet the substantial presence test. Each of those creates a personal filing obligation, and a personal filing obligation is what an ITIN is for.

Because the trigger is a question about your own facts rather than about the structure, a US CPA is the right person to confirm it. The cost of asking is small against the cost of filing something you did not need to file, or missing something you did.

Sources

1. IRS — Employer identification number: https://www.irs.gov/businesses/small-businesses-self-employed/employer-identification-number
2. IRS — Individual taxpayer identification number (ITIN): https://www.irs.gov/individuals/individual-taxpayer-identification-number
3. IRS — Understanding Your IRS Individual Taxpayer Identification Number, Publication 1915: https://www.irs.gov/pub/irs-pdf/p1915.pdf
4. IRS — About Form W-7, Application for IRS Individual Taxpayer Identification Number: https://www.irs.gov/forms-pubs/about-form-w-7
5. IRS — About Form SS-4, Application for Employer Identification Number: https://www.irs.gov/forms-pubs/about-form-ss-4
6. IRS — Understanding Your EIN, Publication 1635: https://www.irs.gov/pub/irs-pdf/p1635.pdf
7. IRS — Taxation of Nonresident Aliens: https://www.irs.gov/individuals/international-taxpayers/taxation-of-nonresident-aliens
8. IRS — Effectively Connected Income (ECI): https://www.irs.gov/individuals/international-taxpayers/effectively-connected-income-eci