Can a US citizen apply for an ITIN instead of a Social Security Number?

No. The instructions for Form W-7 state that an ITIN is for individuals who are required to have a US taxpayer identification number but who do not have and are not eligible to get an SSN, and they direct you not to complete Form W-7 if you are eligible to get one. A US citizen is eligible, as is a person admitted for permanent residence. The instructions also generally require a Social Security Administration denial letter to be attached, and that letter will never be issued to a citizen. A citizen's ITIN application is a dead end.

Can I file the six FBAR years before my SSN arrives?

The FinCEN Form 114 filer section allows a filer with no US taxpayer identification number to identify themselves using an official foreign government document, recording the type, number and country of issue, so a UK passport can be used. That means the filing is technically possible. It is usually still the wrong move, because the six years are meant to be filed as part of a coordinated streamlined submission with the appropriate late-filing reason selected, and filing under a passport number leaves those records disconnected from the returns filed later under your SSN.

Does my UK National Insurance number work as a US taxpayer identification number?

No. A National Insurance number is a UK identifier issued for UK purposes and has no status with the IRS or FinCEN. It cannot be entered on a Form 1040, on Form 14653 or as a US taxpayer identification number on a FinCEN Form 114. It is also not what a UK bank is asking for when it requests a US taxpayer identification number on a FATCA self-certification; that request is for an SSN. The only valid US identifier for a US citizen is a Social Security Number.

What happens if the IRS opens an examination before my SSN is issued?

Eligibility for the streamlined procedures is lost. The IRS Streamlined Filing Compliance Procedures page states that the route is unavailable where the IRS has initiated a civil examination of the taxpayer's returns for any taxable year, whether or not the examination relates to undisclosed foreign financial assets. A pending Form SS-5 application gives you no protection and reserves no place in the queue. That is the practical reason to lodge the citizenship documentation and the SS-5 immediately on identifying the issue rather than after the tax analysis is complete.

Do green card holders and former green card holders face the same problem?

A current lawful permanent resident does, because permanent residents are eligible for a Social Security Number and are therefore barred from Form W-7 in the same way a citizen is. A former green card holder whose status has genuinely been abandoned or revoked may be ineligible for an SSN, and the IRS guidance for taxpayers residing outside the United States allows a streamlined submission from a person ineligible for an SSN provided it is accompanied by a complete ITIN application. The date US tax residence ended has to be established first, because it determines which years the submission must cover.

Streamlined Foreign Offshore Procedures Without an SSN

Q: Can I make a Streamlined Foreign Offshore Procedures submission while my SSN application is pending?

No. The IRS frequently asked questions for taxpayers residing outside the United States deal with exactly this situation and confirm that a person who is eligible for a Social Security Number but does not have one may not use the streamlined procedures. If you file anyway, the IRS may assign an Internal Revenue Service Number and process the returns, but you will not be eligible for the favorable penalty provisions of the streamlined procedures. Prepare everything while the application is with the Social Security Administration, and mail the package once the number is issued.

The Streamlined Foreign Offshore Procedures are closed to a US citizen who does not yet hold a Social Security Number, and the answer is not an ITIN. The IRS is explicit on this point: every return submitted under the streamlined procedures must carry a valid taxpayer identification number, and for a US citizen or resident alien the only valid number is an SSN. If you are an accidental American or a dual US/UK national who has just learned that you have a US filing obligation and have never been issued a number, the correct sequence is to apply for the SSN first on Form SS-5, prepare the three return years and six FBAR years in parallel, and mail the completed package only once the number is in your hands.

That sounds like a delay problem. In practice it is a sequencing problem, and the people who get into difficulty are almost always the ones who tried to skip a step: filing a Form W-7 that was never available to them, mailing a package with the identification box left blank, or e-filing six years of foreign account reports under a UK passport number and then discovering that nothing in the submission ties together. This is a preparation and compliance exercise that has to be run in a specific order, and the order matters more than the speed.

What are the Streamlined Foreign Offshore Procedures?

The Streamlined Foreign Offshore Procedures are an IRS compliance route for individuals living outside the United States whose failure to file US tax returns and foreign financial account reports was non-willful. The IRS defines non-willful conduct on its Streamlined Filing Compliance Procedures page as negligence, inadvertence, or mistake, or conduct that is the result of a good faith misunderstanding of the requirements of the law. The route is not available at all if the IRS has already initiated a civil examination of your returns for any tax year, regardless of whether that examination has anything to do with undisclosed foreign assets.

On the IRS page for US taxpayers residing outside the United States, the non-residency requirement for a US citizen or lawful permanent resident is set out as follows: in one or more of the most recent three years for which the return due date has passed, the individual did not have a US abode and was physically outside the United States for at least 330 full days. The submission itself consists of delinquent or amended returns for the most recent three years, delinquent FBARs for the most recent six years, a signed Form 14653 certification, and payment of all tax due with statutory interest. The paper package is mailed to the IRS at 3651 South I-H 35, Stop 6063 AUSC, Attn: Streamlined Foreign Offshore, Austin, TX 78741, and the FBARs are filed separately and electronically with FinCEN.

Why does a missing SSN block a Streamlined Foreign Offshore Procedures submission?

Because the terms of the programme require a valid taxpayer identification number, and for a US citizen no substitute exists. The IRS Streamlined Filing Compliance Procedures page states that all returns submitted under the streamlined procedures must have a valid taxpayer identification number, and that for US citizens and resident aliens the proper number is a valid SSN. The frequently asked questions for taxpayers residing outside the United States deal with the point head on, asking whether a person who is eligible for an SSN but does not have one at this time may make a submission. The answer is that they may not.

The same answer explains what happens if you ignore that and file anyway. The IRS may assign an Internal Revenue Service Number so that the returns can be processed, but the filer is not eligible for the favorable penalty provisions of the streamlined procedures. An Internal Revenue Service Number, or IRSN, is an internal control number the IRS uses so that a return arriving without a valid taxpayer identification number can still be posted. It is a processing device, not a taxpayer identification number, and it does not rescue the submission. You end up with three years of returns and six years of account reports on the record, the disclosure made, and none of the penalty protection that was the entire reason for using the streamlined route in the first place. That is the worst of both outcomes.

Why can a US citizen not simply apply for an ITIN instead?

An ITIN is not an alternative identifier for people who find an SSN inconvenient. The instructions for Form W-7 define the ITIN as a nine-digit number issued to individuals who are required for federal tax purposes to have a US taxpayer identification number but who do not have and are not eligible to get a Social Security Number. The instructions then say, in terms, not to complete Form W-7 if you have an SSN or if you are eligible to get one, and they confirm that you are eligible if you are a US citizen or have been admitted to the United States for permanent residence or US employment.

There is a second, practical bar. Where the Social Security Administration has notified an applicant that they are ineligible for an SSN, the W-7 instructions require the SSA letter of denial to be attached to the application. A US citizen will never receive that letter, because a US citizen is not ineligible. So a citizen filing Form W-7 is submitting an application that cannot be granted, supported by evidence that cannot exist. Several months are lost, and the streamlined package is no closer to being mailable. This is the most common wrong turn we see, and it is usually taken on the strength of general guidance that treats an SSN and an ITIN as interchangeable. For this reader they are not.

How does a US citizen in the UK apply for a first Social Security Number?

Through the Social Security Administration, using Form SS-5, Application for a Social Security Card. Applicants outside the United States use the SS-5-FS version, and in the United Kingdom the application is handled by the Federal Benefits Unit of the Social Security Administration based at the US Embassy in London rather than by an SSA field office. An applicant aged twelve or over who has never been assigned a number must attend an interview in person and must produce evidence that no number was ever issued to them. Long, documented residence outside the United States is the standard way that evidence is assembled.

The evidence rules are strict and are the usual source of delay. The Social Security Administration accepts original documents or copies certified by the issuing agency; ordinary photocopies and notarised copies are refused. Expect to gather the following before requesting an appointment.

A completed Form SS-5-FS, Application for a Social Security Card
Evidence of US citizenship, such as a US passport, a Consular Report of Birth Abroad, a Certificate of Citizenship or a Certificate of Naturalization
Evidence of age, normally the same citizenship document or a birth record
Evidence of identity, normally a current passport or other photographic identity document
Evidence that no Social Security Number was previously assigned, built from current and expired passports, school records, employment records and other records showing long-term residence outside the United States
Certified English translations for any document not in English

There is a hidden first step for many accidental Americans. A person who was born in the United States and left as an infant, or who acquired citizenship through a parent, often holds no US passport, no Consular Report of Birth Abroad and no Certificate of Citizenship. Before the Social Security Administration can consider the SS-5, the citizenship itself has to be documented through the Passport and Citizenship Unit at the embassy. That is a separate process with its own evidence requirements and its own queue, and it should be started at the same time as the tax preparation work, not after it. Published processing times for both stages move, so confirm the current position with the relevant unit rather than planning against a figure you read once.

How should you sequence the SSN application against the streamlined submission?

Run the two workstreams in parallel and let the SSN gate only the final act of mailing. A workable sequence looks like this.

Document the citizenship first if you do not already hold a US passport, Consular Report of Birth Abroad or Certificate of Citizenship, because the SS-5 cannot proceed without it
Lodge the SS-5-FS with the Federal Benefits Unit and keep the appointment record and any receipt issued, so the date of application is provable
Begin the substantive preparation immediately: reconstruct the UK income picture, convert GBP amounts to USD on a consistent and defensible basis, and identify every reportable foreign interest
Draft the Form 14653 narrative early, while memory and documents are fresh, and keep it factual and specific rather than generic
Keep the six FBAR years fully prepared but unfiled unless there is a positive reason to file earlier
When the number is issued, re-cut the package to the correct three years, insert the SSN throughout, sign, and mail with payment

What happens to the three return years while you wait?

They move. This is the point that almost no published guidance makes, and it catches people out. The streamlined procedures require the most recent three years for which the return due date, including any extension, has passed. That window rolls forward. An SSN application that crosses a filing season means the three years you prepared in the spring are not the three years the package must contain when you finally mail it in the following winter. A year drops off the back and a year is added at the front, and the new year has to be prepared to the same standard, with the same information returns, before anything goes in the envelope.

Almost all of the substantive work is unaffected by the missing number and should be done during the wait. Income reconstruction, the choice between the foreign earned income exclusion and the foreign tax credit, the treatment of UK employment and self-employment income, gains on UK property, and the identification of reportable interests in non-US companies and non-US pooled investment funds all proceed normally. So does the assessment of whether Form 8938 and any information returns such as Form 5471 or Form 8621 are in point for each year. The one thing that genuinely cannot be finished is the identification block on each return, the identification line on Form 14653, and the payment, because a payment sent without a taxpayer identification number and tax year cannot be reliably applied to your account.

Can you file the six FBAR years before the SSN arrives?

Technically yes, and this surprises most people. The FBAR is FinCEN Form 114, filed electronically through the BSA E-Filing System, and it is a Treasury filing that sits outside the income tax return. The filer identification section of Form 114 anticipates filers with no US taxpayer identification number: where the filer does not have one, the form takes an official foreign government document instead, recording the document type, its number and the country of issue. For a UK-resident accidental American that would ordinarily be a UK passport. So the missing SSN does not, by itself, prevent the six years of foreign account reports from being filed.

Filing them early is nevertheless usually the wrong call. The Form 14653 certification is signed under penalties of perjury and covers the whole submission, including the statement that the required FBARs have been filed; the FBARs are meant to be filed as part of a coordinated streamlined submission, with the appropriate reason for late filing selected, so that they are recognisable as belonging to it. Filing six years under a passport number and then filing three returns under a newly issued SSN leaves two sets of Treasury records keyed to two different identifiers, with no automatic link between them. Unless there is a specific reason to move first, prepare all six years, hold them, and file them under the SSN as part of the package. Note also that the standalone delinquent FBAR route that circulated for years should not be relied on: the IRS withdrew its published Delinquent FBAR Submission Procedures page in 2026, and a streamlined submission carries its own mechanism for the six years in any event.

What if the IRS or your UK bank contacts you first?

The risk is real and it is not suspended while the SS-5 is in a queue. Eligibility for the streamlined procedures is lost if the IRS has initiated a civil examination of your returns for any tax year, and it is lost regardless of whether the examination has anything to do with foreign accounts. A pending SSN application is not a shield and does not reserve your place. This is the strongest argument for starting the citizenship documentation and the SS-5 on the same day you identify the problem, rather than waiting for the tax analysis to be finished.

The UK bank is usually how the whole thing starts. A UK financial institution that has picked up an indicator of US status will ask for a self-certification and a US taxpayer identification number. HMRC guidance in the International Exchange of Information Manual at IEIM403180 addresses self-certifications that are invalid solely because a taxpayer identification number is missing, and makes clear that the presence of indicia of US tax residence or US citizenship changes the analysis; it also confirms that an institution which knows or has reason to know a self-certification is incorrect or unreliable must obtain a valid one, or a reasonable explanation with supporting documentation. The practical rule is simple. Answer the bank accurately, state that an SSN application has been lodged and give the date, and never sign a self-certification that denies US status in order to make the correspondence stop. A false self-certification converts a straightforward non-willful position into something else entirely, and Form 14653 will later ask you to explain your conduct.

A worked example: an accidental American partner in London

Marcus Whitfield is 46, a partner at a London investment firm, and was born in Boston while his British parents were on a two-year posting. The family returned to Surrey before his second birthday and he has never been back. He holds a UK passport only. In March his private bank writes to him because his file records a US place of birth, and asks for a self-certification and a US taxpayer identification number. He has never had a Social Security Number, has never filed a US return, and has a UK income and asset profile that includes employment income, carried interest arrangements, a substantial holding in a UK trading company, and UK-domiciled funds.

The order of work is fixed by the SSN constraint. He replies to the bank accurately and confirms that he is documenting his position. He applies to the embassy for a Consular Report of Birth Abroad and a first US passport to evidence citizenship, then lodges Form SS-5-FS with the Federal Benefits Unit and attends the in-person interview, producing his expired and current UK passports, school records and employment history as evidence that no number was ever assigned. In parallel, the three return years are built out: the foreign tax credit position on his UK employment income, the treatment of his fund holdings, whether his shareholding in the UK trading company triggers a Form 5471 filing category, and Form 8938 for each year. Six FBAR years are prepared and held. The number arrives after the following filing season has closed, so the three-year window has rolled: the earliest year prepared is dropped, the newest year is prepared, and the package is re-cut. Form 14653 is finalised with his SSN and a specific narrative explaining that he left the United States as an infant, held no US documentation, and had no reason to think a US filing obligation applied to him. Returns, certification and payment of tax and statutory interest go to Austin; the six FBARs are e-filed under the SSN the same week.

How is the package assembled once the SSN arrives?

Three years of Forms 1040 with all schedules and every applicable international information return, each carrying the new SSN
Streamlined Foreign Offshore written in red at the top of the first page of each return and information return
A signed Form 14653 certifying eligibility, the non-residency test, that the required FBARs have been filed, and that the failures were non-willful, with a specific factual narrative rather than a generic one
A copy of the signed certification attached to each return in the package
Payment of all tax due together with statutory interest, identified with the SSN and the correct tax year
Six years of FinCEN Form 114 e-filed through the BSA E-Filing System under the SSN, with the streamlined reason for late filing selected
The paper package mailed to the Austin address; the returns in a streamlined submission are not e-filed

Expect silence afterwards. The IRS does not issue an acceptance letter for a streamlined submission and there is no closing agreement. Absence of correspondence is the normal outcome, and the file should be retained in full, including the SS-5 evidence, on the basis that it may need to be produced years later.

What about green card holders and former green card holders?

A current lawful permanent resident is in the same position as a citizen. Because a person admitted for permanent residence is eligible for a Social Security Number, Form W-7 is barred to them in the same way, and the SS-5 route applies. The non-residency test they must meet under the Streamlined Foreign Offshore Procedures is also the same 330-day, no-US-abode test that applies to citizens, which is a different question from whether the green card itself has been formally abandoned.

A former green card holder is the one group in this discussion for whom the ITIN is genuinely relevant. Someone whose permanent residence has been formally abandoned or revoked may no longer be eligible for a Social Security Number, and the IRS guidance for taxpayers residing outside the United States provides for exactly that case: a person who is ineligible for an SSN and does not have an ITIN may make a streamlined submission provided it is accompanied by a complete ITIN application. Before that route is used, two questions have to be settled. First, whether US tax residence actually ended, and on what date, because holding an expired card is not the same as having abandoned status and the answer determines which years are in scope. Second, whether the Social Security Administration would in fact refuse a number, since the W-7 evidence requirements are built around a denial.

Is there an IRS route that tolerates a missing SSN?

Yes, but only for people who have already given up citizenship, and the contrast is instructive. The IRS Relief Procedures for Certain Former Citizens address this directly: the guidance states that a person who does not have an SSN may still make a submission under those procedures, leaving the boxes where an SSN is requested blank. Those procedures are narrow. They apply to individuals who relinquished US citizenship after 18 March 2010, who have no filing history as a US citizen or resident, whose net worth is below USD 2,000,000 both at expatriation and at the time of submission, whose aggregate tax liability is USD 25,000 or less for the year of expatriation and the five preceding years, and whose failures were non-willful. Six tax years of returns are required.

The point for a reader who is still a citizen is that the door is closed. The IRS operates one route that expressly tolerates a missing identification number and one that expressly does not, and the difference turns on whether you are still a US citizen. A high-net-worth individual with UK assets will in most cases fail the net worth threshold in any event, which makes the Streamlined Foreign Offshore Procedures the realistic route and the SSN a genuine prerequisite rather than an administrative formality that can be worked around.

Where this goes wrong most often

Filing Form W-7 as a US citizen, which cannot succeed and costs months
Mailing the streamlined package with the identification box blank or marked applied for, which invites an IRSN and forfeits the penalty terms
E-filing the six FBAR years early under a UK passport number and never reconciling them to the SSN used on the returns
Letting the three-year window roll during the SSN wait and mailing a package built on the wrong years
Signing a bank self-certification that denies US status while the SSN application is pending
Treating the withdrawn delinquent FBAR route as a live alternative to a streamlined submission
Writing a Form 14653 narrative in general terms instead of setting out the specific personal and financial facts the IRS asks for

None of these is difficult to avoid. All of them follow from treating the missing Social Security Number as a paperwork detail rather than as the gating item it is. Handled in the right order, the absence of a number costs time and nothing else: the citizenship is documented, the SS-5 goes in, the three years and six years are built while the application is processed, and the package is mailed complete and correctly identified on the day the number lands.