The standard way to apply for an ITIN is to post your actual passport to the IRS in Austin, Texas, and wait. Not a copy — the physical document, unless you can obtain a certified copy from the issuing authority itself, which for most passports means applying to your own government and waiting again.
For anyone who travels, works, or simply dislikes posting their identity document across the world for an indefinite period, that is an unattractive proposition. It is also avoidable. A Certifying Acceptance Agent can verify your passport in person or remotely and certify it to the IRS, so the original never leaves your possession.
This guide covers what an ITIN is for, the more useful question of whether you need one at all, how the CAA route works, and the expiry rules that catch out people who obtained one years ago.
The short answer
- An ITIN is a tax processing number for individuals who must appear on a US tax filing but cannot get a Social Security Number.
- Many non-resident LLC owners never need one. If your company files Form 5472 and you have no personal US filing requirement, an ITIN may be unnecessary.
- You apply on Form W-7, normally attached to a US tax return.
- A Certifying Acceptance Agent verifies your passport and certifies it, so you do not post the original to the IRS.
- ITINs expire after three consecutive years without appearing on a return.
What an ITIN is, and is not
An ITIN is a nine-digit number issued by the IRS, formatted like a Social Security Number and always beginning with 9. Its only purpose is tax administration: it lets the IRS process a return or a withholding document for someone who has a filing obligation but no SSN.
It does not authorise you to work in the United States. It confers no immigration status and is not evidence of any. It does not entitle you to Social Security benefits or to most tax credits. It is not a business number — that is an EIN — and holding one does not by itself create a US tax liability.
Understanding that boundary matters, because a great deal of low-quality advice presents the ITIN as a general-purpose key to operating in the US. It is a filing number and nothing more.
Do you actually need one?
This is the question worth answering before you spend anything, because a significant share of the founders who ask us for an ITIN turn out not to need one.
If you own a US LLC from abroad, the company’s federal obligation is Form 5472 with a pro forma 1120, which is filed under the company’s EIN. That filing does not require you personally to hold an ITIN.
You are likely to need one where you personally must file or appear on a US return: because you have income effectively connected with a US trade or business and must file Form 1040-NR; because you are claiming a treaty benefit on US-source income; because you are a partner in a US partnership receiving a Schedule K-1; because you have US rental income or gains from US real estate; or because a withholding agent needs to report payments to you.
Some banks also ask for one during onboarding. That is a commercial preference rather than a legal requirement, and it varies by institution — worth checking with the specific provider before starting an application on their account.
Form W-7 and reason codes
The application is Form W-7, and its most important field is the reason you are applying. Choosing the wrong code is a common cause of rejection.
| Code | Applies to |
|---|---|
| a | Non-resident alien claiming a tax treaty benefit |
| b | Non-resident alien filing a US tax return |
| c | US resident alien filing a US tax return |
| d | Dependent of a US citizen or resident alien |
| e | Spouse of a US citizen or resident alien |
| f | Non-resident student, professor or researcher |
| g | Dependent or spouse of a non-resident alien visa holder |
| h | Other, with the reason stated |
Most non-resident founders apply under b, or under a where a treaty position is being claimed. The name on the form must match the passport exactly, including the order of given and family names, which is a frequent source of avoidable delay.
The passport problem
The IRS must verify your identity and your foreign status. A passport is the only single document that proves both, which is why it is the usual choice.
Applying directly, you have two options. Post the original passport with your application, or supply a copy certified by the issuing agency — meaning the passport authority that issued it, not a notary, not a solicitor, and not an embassy of another country.
Both are painful. Posting the original means being without it for the whole processing period, with international post at both ends. Obtaining an issuing-agency certified copy is a separate bureaucratic exercise in your own country, and some authorities will not provide one at all.
What a Certifying Acceptance Agent does
A Certifying Acceptance Agent is a person or firm authorised by the IRS under a formal agreement to verify identity documents for ITIN applicants.
The CAA inspects your passport, satisfies itself the document is genuine and belongs to you, and issues a Certificate of Accuracy which is submitted with the W-7 in place of the document itself. The IRS accepts the agent’s verification because the agent has signed an agreement making itself accountable for that verification.
The practical effect is straightforward: your passport stays with you. A CAA can also review the whole application before it goes in, which matters when a rejection costs weeks rather than days.
One limitation worth knowing: a CAA can certify your passport and, in most cases, dependants’ documents are treated more restrictively. If you are applying for children as well as yourself, confirm what the agent can and cannot certify before you begin.
The three routes compared
| Post originals | Certifying Acceptance Agent | IRS Taxpayer Assistance Centre | |
|---|---|---|---|
| Passport leaves your possession | Yes | No | No |
| Works from outside the US | Yes | Yes | No |
| Application reviewed before filing | No | Yes | Partly |
| Cost | Postage only | Agent’s fee | Free |
| Main drawback | Weeks without your passport | Fee | Requires being in the US, by appointment |
For an applicant outside the United States, the Taxpayer Assistance Centre route is not realistically available, which leaves posting the original or using an agent.
The tax return requirement
An ITIN is issued to let you file, so the default rule is that Form W-7 is submitted attached to a completed US tax return. You cannot usually obtain one speculatively in advance of any filing need.
There are recognised exceptions where the number is needed for a purpose other than filing a return — for example where a withholding agent must report payments to you, where treaty benefits are being claimed on certain income, or in some mortgage and property situations. These require documentation from the relevant party evidencing the need.
If someone offers to obtain you an ITIN with no return and no exception documentation, be sceptical. That application will most likely be rejected, and you will have paid for it.
Two applicants, two outcomes
The founder who did not need one
Bilal owns a single-member Wyoming LLC providing design services to US clients, all work performed from Karachi. A formation service told him an ITIN was a required step and quoted him for it.
On review, his company files Form 5472 under its EIN and he has no personal US filing obligation. He needed no ITIN. Had he applied anyway, with no return attached and no exception, the application would very likely have been rejected — after several months of waiting.
The applicant who did
Ayesha holds a rental apartment in Florida through a US LLC and receives rental income. She must file Form 1040-NR personally, so she needs an ITIN.
She used a CAA: passport verified remotely, Certificate of Accuracy issued, W-7 filed with her return. Her passport never left Karachi, and the ITIN was issued in time for the filing deadline. Had she posted the original instead, it would have been in Texas during a period when she needed to travel.
How long it takes
Plan for around seven to eleven weeks in normal conditions, and longer between January and April when the IRS is processing the filing season. Applications from outside the United States sit at the slower end of that range.
The number arrives by post in a notice from the IRS. Store it carefully — it is not reissued casually, and you will need it for every subsequent filing.
Expiry and renewal
This is the rule that most often surprises people who obtained an ITIN years ago and assumed it was permanent.
An ITIN expires if it does not appear on a US federal tax return for three consecutive years. It lapses on 31 December of that third year, and to use it again you must apply to reactivate it — which takes as long as the original application.
Separately, ITINs with certain middle digits were retired in phases between 2016 and 2020. If yours has been dormant for years, check its status before you rely on it rather than discovering the problem at a filing deadline.
Renewal uses the same Form W-7 with the renewal box marked, and the same document verification requirement — so a CAA is just as useful for renewals as for first applications. Filing a return with an expired ITIN causes processing delays and can hold up any refund.
What documents the IRS accepts
The IRS publishes a list of acceptable documents, and the practical distinction is between those that prove identity, those that prove foreign status, and the one document that does both.
| Document | Proves identity | Proves foreign status |
|---|---|---|
| Passport | Yes | Yes — the only stand-alone document |
| National identity card | Yes | Yes |
| Foreign driving licence | Yes | No |
| Foreign voter registration card | Yes | Yes |
| Foreign birth certificate | Yes | Yes, if issued abroad |
| US driving licence | Yes | No |
A valid unexpired passport is the simplest route because it alone satisfies both tests. Without one you must supply two documents from the list, at least one of which establishes foreign status, and each must be certified to the same standard — which multiplies the work considerably.
Documents in a language other than English generally need a certified translation. Check this early: obtaining one can take longer than the rest of the application.
What it costs
The IRS charges nothing to issue an ITIN. Every cost you meet is for professional help or postage.
Posting the application yourself costs only secure international postage in both directions — though “cheap” is doing some work in that sentence, given you are posting your passport. A Certifying Acceptance Agent charges a fee that covers document verification, the Certificate of Accuracy, and review of the application before it is filed.
The real economics are about failure, not fees. A rejected application means another two to three months, and if it was rejected for a document problem you may be posting your passport a second time. Paying for review is generally cheaper than paying for a second attempt.
Why applications get rejected
- No tax return attached and no valid exception documented.
- Uncertified document copies — an ordinary notarised copy is not accepted.
- Name mismatch between the W-7, the passport and the return.
- Wrong reason code for the applicant’s actual circumstances.
- Expired passport submitted as evidence.
- Incomplete foreign address, which the IRS requires even where you also give a US one.
What the number is actually for once you have it
An ITIN on its own does nothing. It becomes useful at the moment you hand it to somebody, and for most people that means one of two documents.
Form W-8BEN is the certificate you give to a US payer confirming you are a foreign individual. It goes to the payer, not to the IRS, which surprises people who expect to file it. The payer keeps it and relies on it.
Why it matters is withholding. Certain categories of US-source income paid to a foreign person — royalties, licence fees, some interest and dividends — carry a default withholding rate of 30%. The payer deducts it and sends it to the IRS before you see any of it. A valid W-8BEN is what stops the payer applying that rate blindly, and where a tax treaty between the US and your country sets a lower rate, Part II of the form is where you claim it.
Claiming a treaty rate generally requires a taxpayer identification number, and for several categories of income the IRS requires that it be a US one. That is precisely the situation the exception routes exist for, and it is the most common legitimate reason a founder needs an ITIN without owing a return.
Two things to keep track of. A W-8BEN is valid from signing until the end of the third following calendar year, so it expires quietly and the payer starts withholding at the full rate until you send a new one. And if you are certifying on behalf of a company rather than yourself, the entity version is Form W-8BEN-E, which is a longer form and a different exercise.
The other document is Form 1040-NR, the non-resident return. If tax has already been withheld at 30% when a treaty entitled you to less, reclaiming the difference means filing that return — and the return needs the ITIN. This is the circularity that catches people: the number you needed to avoid the withholding is the same number you now need to get it back.
If the IRS writes back
Two notices arrive often enough to be worth recognising on sight, and they mean different things.
CP566 says the IRS needs more information before it can decide. This is not a refusal. It names what is missing — usually a document, a signature or a clarification — and gives you a limited window to supply it. Answer it within the window and the application continues from where it stopped. Miss the window and it converts into a rejection, at which point you start again.
CP567 says the application has been rejected, and gives a reason. There is no appeal against it in the ordinary sense. What you do is fix the defect and submit a fresh Form W-7 with a complete package.
Read the stated reason carefully rather than assuming. A rejection for uncertified documents is a different problem from a rejection for the wrong reason code, and reapplying with better copies when the real issue was the code wastes another cycle of several weeks.
Your original documents are returned separately from the notice, and typically later — often several weeks after. Do not assume they are lost because the letter arrived alone, and do not send a replacement passport into a second application until the first one is back in your hands.
Where a return was attached to the rejected application, it does not simply disappear. It is generally processed without a valid identifying number, which can produce its own follow-up correspondence. This is the strongest practical argument for using a Certifying Acceptance Agent on the first attempt rather than the second: the failure mode is not just delay, it is a return sitting in the system in a state you then have to correct.
Frequently asked questions
Do I need an ITIN to open a US business bank account?
Usually not — the account belongs to the company and runs on its EIN. Some institutions ask for one as part of their own checks, so confirm with the specific provider first.
Do I need an ITIN before I can get an EIN?
No, and this myth costs people months. Write “Foreign” on line 7b of Form SS-4 and apply for the EIN directly.
Can I apply from outside the United States?
Yes. Either post the application to the IRS or use a Certifying Acceptance Agent, who can work with you remotely.
Does an ITIN let me work in the US?
No. It has no immigration effect whatsoever and does not authorise employment.
What if my passport is my only identity document?
That is fine — a valid passport is the only document that establishes both identity and foreign status on its own. Other combinations require two documents.
Can my spouse and children get ITINs at the same time?
Each person needs their own W-7 and their own documentation. Dependants face stricter document rules, so check what your agent can certify before applying as a family.
How do I check whether my existing ITIN is still valid?
Work out whether it has appeared on a federal return in the last three years. If not, assume it has expired and plan to renew before your next filing.
Is there a fast-track option?
No expedited service exists. What you can control is accuracy — a rejected application restarts the clock, so getting it right first time is the only meaningful way to save time.
Getting it handled
The two decisions that matter are whether you need an ITIN at all, and if so whether you are willing to post your passport. The first saves money when the answer is no; the second is why the Certifying Acceptance Agent route exists.
We prepare ITIN applications for non-residents as an IRS Certifying Acceptance Agent, so your passport stays with you, and we will tell you honestly if your situation does not require one. See our ITIN service or get in touch.
This article is general information, current as at September 2026, and is not tax advice. Remotix BPO is a business process outsourcing company and is not an accounting firm or a law firm. IRS procedures change — confirm current requirements before applying.
