How to get an ITIN: IRS tax number for non-residents

The ITIN only makes sense when there is a federal tax purpose: W-7, W-8BEN, withholding, 1040-NR, FIRPTA, K-1, royalties or broker requirements.

If you live outside the United States but the IRS expects something from you, withholding to recover, federal taxes to declare, US dividends, an LLC with a pending Form 1040-NR, a Florida property sale subject to FIRPTA withholding, royalties from an Amazon KDP book, there is one filing you cannot escape: the ITIN. It is the tax piece that identifies you before the IRS when you are not a resident and therefore cannot have a Social Security Number (SSN). Without an ITIN the loop never closes: no refunds, no clean application of the US-Spain tax treaty, no completion of the US filings the system demands when your name appears as a taxpayer.

It is also one of the worst-explained processes in the whole American universe. The IRS website sends you to a PDF, the PDF sends you to another PDF, on the way they ask for original passports, mention a Certifying Acceptance Agent (CAA), introduce TAC offices by appointment, route documents to Austin (Texas) and, if you tick the wrong box on Form W-7, you receive a CP-566 Notice six months later with the application rejected. No ITIN, no refund, and in many cases no practical way to file the US return you needed.

At Exentax we have closed hundreds of ITIN cases for residents in Spain and Latin America. This guide is the real version: what it is for, when you need it, how to apply, how long it takes, the typical mistakes, and why having an American team handling the W-7 prevents most rejections. If after reading you decide you need one, we can prepare the file, coordinate certification and follow the IRS process with you.

What the ITIN actually is

The ITIN (Individual Taxpayer Identification Number) is a nine-digit tax number, formatted 9XX-XX-XXXX, issued by the IRS to individuals who have an obligation or right to file a US tax return or form and who are not eligible for a Social Security Number. It lives in the IRS TIN database alongside the SSN and the EIN (the latter being the entity-level number, the one your LLC uses).

What an ITIN is not:

It does not authorize you to work legally in the US.
It does not grant Social Security or Medicare benefits.
It is not a residence permit or a visa.
It does not exempt your foreign-owned LLC from Form 5472.

What an ITIN does:

Identifies you as an individual taxpayer before the IRS.
Lets you file Form 1040-NR (non-resident return).
Enables refund claims for excess withholding (for example the 30% withheld on dividends, royalties, real estate sales or prizes).
Allows US payors and brokers to apply your W-8BEN correctly.
Is the number that appears on any K-1 issued to your LLC with foreign partners.
Is mandatory for dependents/spouses declared on a US return.

Why the ITIN matters more than it looks

The ITIN is not administrative decoration. It is the number that lets a non-resident individual exist cleanly inside the US tax system when there is income, withholding or a personal filing to close. Without that identifier, many files remain technically unfinished: the broker withholds by default, a platform cannot apply the W-8BEN properly, a FIRPTA sale cannot recover excess withholding, or a K-1 is documented with friction.

The key is not to confuse it with other numbers. The EIN identifies the LLC. The ITIN identifies the individual member when that person, not only the entity, has to appear before the IRS. It does not replace the LLC's W-8BEN-E and it does not change your tax residence. If you live in Spain, Portugal, France, Mexico or Colombia, you still report where you are resident. The ITIN simply organizes the US side of your personal file.

At Exentax we do not request ITINs by default. We decide with one practical question: is there withholding, a personal return, a broker, a K-1, FIRPTA, royalties or a treaty claim that needs it? If not, we do not add another filing. If yes, we prepare it properly from the start so the number unlocks the rest of the system: W-8BEN, broker onboarding, filings and withholding recovery.

> If you want to understand the role of the W-8BEN and why it works so well alongside a properly issued ITIN, see the <a href="/en/blog/w-8ben-and-w-8ben-e-fatca-and-withholding">complete W-8BEN and W-8BEN-E guide</a>.

When you need an ITIN: the six typical cases

Not everyone needs an ITIN. Before spending time and money, check that your situation fits one of the following six scenarios. These are the ones we see every week at Exentax:

The typical cases in detail

Refund of excess withholding on US dividends. You live in Spain, hold US shares through a broker (IBKR, Charles Schwab, Fidelity) and receive dividends. Without a working W-8BEN with a valid foreign TIN, the broker withholds 30%. With an ITIN and the W-8BEN, you typically drop to 15% under treaty. If you have already been over-withheld, the refund flows through a Form 1040-NR + W-7.
Royalties from Amazon KDP, Apple, SaaS platforms or YouTube. Platforms such as Amazon KDP, Apple Books, Adobe Stock or some US affiliate programs withhold 30% if they do not receive a valid W-8BEN with a TIN. A properly issued ITIN brings withholding down to 0%, 5% or 10% depending on the type of income and the applicable treaty.
Sale of US real estate with FIRPTA withholding. If you sell US real estate as a non-resident, FIRPTA withholds 15% of the gross sale price. To recover the difference between withholding and actual tax (often thousands or tens of thousands of dollars), a Form 1040-NR must be filed. No ITIN, no return.
Foreign partner in a US entity with K-1. If you are part of a multi-member LLC or US partnership, you will receive a Schedule K-1 each year with your share of the profits, and the entity must withhold (Form 8804/8805). To report properly and recover any excess, you need an ITIN.
Spouse or dependent on a US return. When someone files in the US and wants to include a non-resident spouse or children, that spouse/child needs an ITIN.
Prizes, scholarships, US speaking engagements. If you have received a prize, a scholarship from a US university program, or one-off income from speaking, the most likely outcome is 30% withholding and the need for an ITIN to recover whatever can be recovered.

There is a more subtle seventh profile: the single-member LLC owner who, strictly speaking, does not need an ITIN to file Form 5472 + 1120 pro forma (the LLC is identified by its EIN and the foreign owner box only requires name, address and country of tax residence). But if that same person also has personal US-source activity that triggers a Form 1040-NR (FIRPTA, dividends, K-1 from another structure), the ITIN stops being optional.

The document stack: W-7, tax return, identification

The ITIN process revolves around three elements. Skipping any of them is essentially a guarantee of rejection:

Form W-7 (Application for IRS Individual Taxpayer Identification Number). This is the application itself. It contains a decisive box, the Reason for submitting, which must be ticked with the correct code (a, b, c, d, e, f, g, h). Each reason carries its own supporting documentation. Choosing the wrong box is the most frequent mistake.
US tax return justifying the ITIN. Save for narrowly defined exceptions (typically: applying a tax treaty to passive income via W-8BEN with a US payor), the W-7 is filed together with the tax return that motivates the application (1040-NR, joint 1040 with US spouse, 1042-S, 8288 FIRPTA, etc.). Without that return, the ITIN is rejected for lack of cause.
Identity proven with original document or certified copy. The IRS requires identity verification with a passport (the only single document that covers both identity and "foreign status" alone). There are three valid ways to prove it: (a) mail the original to Austin (Texas), (b) attend a US TAC office, or (c) go through a CAA (Certifying Acceptance Agent) authorized to verify the passport in person and issue a Certificate of Accuracy.

This is where most applicants residing in Spain get stuck. Mailing your original passport to Texas for weeks is not a reasonable option for almost anyone. Travelling to a TAC in the US is not either. That is why the CAA route is the one that makes sense.

How we do it at Exentax: a structured ITIN process

At Exentax we work with the CAA network and run the ITIN as a closed process. Your only task is to send us the documents we ask for and sign the W-7 when ready. We handle the rest:

Pre-diagnosis. Before touching anything, we confirm you actually need an ITIN (not every case does) and, more importantly, under which reason of the W-7 you will apply. Ticking the right "Reason for submitting" box is what separates an approved application from a CP-566 Notice six months later.
Preparation of the supporting tax return. If your reason requires Form 1040-NR (FIRPTA, dividends, K-1, etc.), we prepare it. If your case is one of the exceptional W-8BEN paths, we document it correctly.
Identity verification by CAA. We coordinate the passport verification through the CAA network. You do not mail your original passport to Texas. Verification happens securely.
Filing and follow-up. We package W-7 + return + Certificate of Accuracy + any supporting documents and send it to the IRS. We track the case and notify you when the ITIN is issued.
IRS notices. If a CP-566, CP-567 or any IRS communication arrives, we answer it for you.
Post-issuance application of the ITIN. Once issued, we hand you a short action plan: how to apply it at your broker, on Amazon KDP, on Stripe, on your W-8BEN and on every form where you used to write "applied for" or "N/A".

Real timing today

The IRS official timeframe is 7 to 11 weeks from receipt. The reality of the last twelve months, especially between January and June (peak return season), is closer to 3 to 5 months for many cases. Applications filed between July and November tend to move faster and we go back to the 8-12 week range.

Three factors speed up or slow down the process:

Quality of the W-7. A complete application, with the correct reason, well-prepared return and CAA verification, almost never receives a notice. A W-7 with the wrong boxes ticked is the number-one cause of delay.
Filing season. Sending between February and April means queue.
Physical documents. If you go through the mail-your-passport route, add weeks for the document to travel. That is why we always recommend the CAA route.

Costs and common mistakes

The IRS does not charge a fee to issue an ITIN. The costs in the process are the CAA fee and, where applicable, the 1040-NR preparer fee. At Exentax we work with a closed quote for the managed ITIN process communicated upfront, with no surprises. The six most typical mistakes we see when someone tries to do the ITIN alone are always the same:

Ticking the wrong reason on the W-7 (especially confusing reason "b" with reason "h" or applying reason "a" without an applicable treaty).
Sending the W-7 without the supporting return when one was mandatory.
Sending plain passport copies instead of original or certified copies.
Providing a poorly formatted foreign address (non-US zip codes, non-standard country abbreviations).
Failing to sign the W-7 by hand, in ink, with the correct date.
Applying for an ITIN for profiles that do not actually need one (typically single-member LLC owners with no personal US activity).

Any of these mistakes leads to a CP-566 or CP-567 Notice and, in the worst case, to redoing the process from scratch the next year.

ITIN, banking and your LLC operating stack

If you are starting and have not yet set up the LLC, the natural path is to work both pieces in parallel: <a href="/en/blog/us-llc-vs-spanish-autonomo-structure-banking-tax">the LLC as an alternative to self-employment</a>, the <a href="/en/blog/ein-for-a-us-llc-without-ssn-or-itin">EIN</a> and, where it applies to your personal situation, the ITIN. And if you already have an LLC but you are receiving US withholding you do not understand, the missing piece to clean up the situation is almost always this one.

Renewal and expiration: beware of dormant ITINs

An ITIN can expire. The IRS rule is that an ITIN not used on a tax return for three consecutive years becomes inactive. ITINs issued before 2013 have been renewed in batches based on the middle digits. In practice, if your ITIN has been dormant for years and you suddenly need it again (because you sold a property or you have US dividends again), check whether it is still active before applying it. If not, it is reactivated with a W-7 ticking "renew an existing ITIN".

Why having Exentax behind you changes the outcome

The ITIN looks like a minor filing until you try to do it alone and discover that the IRS does not return calls, the form has nuances only learned after dozens of cases, and one rejection can cost you another full year without recovering your withholding. What our team brings is precisely the opposite: a known process, a secure CAA verification, a supporting return prepared by US accountants, and the certainty that if any notice arrives, we answer it on time.

If you think you need an ITIN, for your broker, for Amazon, for a FIRPTA sale, for a K-1, for a pending refund, or to finally clean up your situation with the IRS, book a strategic review and we will review your case in 30 minutes. If after the call it makes sense to move forward, we send you a closed quote and start the process that same week. And if the real question is whether the LLC/ITIN route fits before you move, we map residence, broker access, withholding, W-8BEN, IRS forms and local reporting with you before opening the file.

Each case is individual. US legislation evolves and the IRS tightens validation criteria every few years. But the principle stays the same: without an ITIN the tax loop with the United States does not close, and building that loop properly is what separates the person who recovers their withholding from the one who silently loses it every year.

Use the ITIN only for a defined purpose

The ITIN application reads more calmly when it's treated as a stable, documented procedure than as a one-time event. The required pieces — a valid Form W-7, a federal tax filing reason that triggers the need for an ITIN, and an identity document accepted by the IRS — define a discrete process that doesn't change from one year to the next.

A short, dated note in the personal folder that records the version of Form W-7 used, the federal filing reason cited, the identity document submitted and the channel through which it was sent makes the application reviewable in a few minutes if the IRS comes back with a question or a deficiency notice. The same note also makes it much easier to handle the renewal cycle on time, instead of starting from scratch when the ITIN expires.

> <a href="/en/book">Review my structure</a>

For an ITIN case, the relevant question is the valid tax purpose behind the application. The number supports a fiscal or financial file; it does not repair a weak LLC structure or replace the documentation that explains ownership and activity.

FinCEN and IRS reporting requirements moved recently; the current state is:

EIN and notice. Without an EIN you cannot file Form 5472. The IRS does not warn before imposing penalties; you find out when an EIN is flagged or a later filing is rejected. In an Exentax file, the source record comes first and the response follows from it.