What is IRS Letter 3800?

Letter 3800, Warning for Report of Foreign Bank and Financial Accounts (FBAR) Apparent Violations, is the letter an IRS examiner issues when an FBAR violation is found but no penalty is warranted. Under IRM 4.26.16.5, examiners either issue Letter 3800 or determine a penalty. It gives the recipient 30 days to respond and expects accurate delinquent or corrected FBARs to be filed before the case closes.

Does a missed FBAR warning letter mean I will never be penalised?

No. A warning letter means no penalty for the years examined, provided you file accurate FBARs as instructed. If you do not, the examiner can consider penalties for the continued failure. The IRM also gives an example in which someone who received a warning letter and later fails to file an FBAR may face the willful penalty, because the letter shows they knew the rules.

Can I use the Streamlined procedures after the IRS opens an examination?

No. The IRS states that if it has initiated a civil examination of your returns for any taxable year, whether or not it relates to foreign assets, you are not eligible for the Streamlined Filing Compliance Procedures. That is why UK-based Americans with a missed FBAR should act before contact, when the Streamlined Foreign route offers no penalty for eligible non-willful filers.

How long does the IRS have to assess an FBAR penalty?

Six years from the date of the violation, under 31 USC 5321(b)(1). For 2016 and later years, the IRM treats 15 April of the following year as the violation date if an accurate FBAR was not filed by the 15 October extended due date. Only the filer's consent extends it, and a consent for an income tax examination does not extend the FBAR statute.

How does the IRS learn about my UK bank accounts?

Under FATCA, foreign financial institutions report on accounts held by US account holders. The UK implements this through an intergovernmental agreement under which UK banks and investment firms report to HMRC, which shares the information with the IRS. GOV.UK confirms that UK institutions may ask customers for information because international agreements allow tax authorities to exchange financial account data.

Do I also need to tell HMRC about accounts in an IRS FBAR examination?

Usually not for UK accounts on which UK tax was paid. But if you are UK resident and have unreported income or gains from accounts or assets outside the UK, such as a US brokerage account, HMRC treats that as an offshore matter. Its Worldwide Disclosure Facility lets you notify HMRC, complete the disclosure within 90 days and pay on submission.

Missed FBAR: What an IRS Warning Letter Means

A missed FBAR that surfaces during an IRS examination does not automatically end in a penalty: under the Internal Revenue Manual, an examiner who finds an FBAR violation must either determine a penalty or issue Letter 3800, the FBAR warning letter, and a warning letter is the outcome when the examiner concludes that no penalty is warranted. For a UK-based American, that letter is the best realistic result once an examination has begun, but it is conditional. It demands accurate delinquent FBARs within a short window, it is not a closing agreement on your tax position, and it changes how the IRS will view any future failure.

This guide explains the FBAR examination path for Americans living in the UK, when examiners close a case with a warning rather than a penalty, how to respond, and why getting compliant before the IRS makes contact is far better than hoping for leniency. It also covers HMRC's parallel position on the same accounts.

What is a missed FBAR and why does it matter to UK-based Americans?

The FBAR is FinCEN Form 114, the Report of Foreign Bank and Financial Accounts. A missed FBAR is a report that was required but not filed, or filed late or inaccurately. According to FinCEN at https://www.fincen.gov/report-foreign-bank-and-financial-accounts, a United States person with a financial interest in, or signature authority over, foreign financial accounts must file an FBAR if the aggregate value of those accounts exceeds $10,000 at any time during the calendar year. For an American living in London, Edinburgh or Manchester, that threshold is crossed by an ordinary current account, an ISA, a workplace share plan account or a brokerage account with very little effort.

The FBAR is not a tax return. It is a Bank Secrecy Act report filed with FinCEN through the BSA E-Filing System, separately from Form 1040. The Internal Revenue Manual at https://www.irs.gov/irm/part4/irm_04-026-016 states that the IRS assesses FBAR penalties under Title 31, and that provisions of the Internal Revenue Code generally do not apply to FBARs. Different rules on deadlines, statutes of limitation and agreements follow.

In the returns we prepare, the typical missed FBAR is not concealment. It is a banker on secondment who assumed UK accounts were a UK matter, or a business owner unaware that signature authority over a company account is reportable.

When does the IRS issue a warning letter for a missed FBAR?

The governing text is IRM 4.26.16.5. It says that when there is an FBAR violation, the examiner will either issue the FBAR warning letter, Letter 3800, titled Warning for Report of Foreign Bank and Financial Accounts (FBAR) Apparent Violations, or determine a penalty. The manual also states that civil FBAR penalties have varying upper limits but no floor, and that the examiner has discretion in determining the amount of the penalty, if any.

A warning letter is therefore the examiner's formal acknowledgement that a violation occurred, combined with a decision that none of the penalties for violating the FBAR reporting rules is warranted on the facts. The IRM's examiner discretion section, IRM 4.26.16.5.2.1, says examiners may consider whether issuing a warning letter and securing delinquent or amended FBARs, rather than determining a penalty, will achieve the desired result of improving future compliance. The manual frames the purpose of FBAR penalties as promoting compliance with the reporting and recordkeeping rules, not raising revenue.

The factors the IRM lists for exercising that discretion include, but are not limited to, the following:

Whether compliance objectives would be achieved by issuing a warning letter.
Whether the person had previously been issued a warning letter or assessed an FBAR penalty.
The nature of the violation and the amounts involved.
The filer's conduct contributing to the violation.
Whether the filer cooperated during the examination.
The balance in each account during the year.
The total amount of all penalties to be asserted for all violations.

There is one important procedural limit. The IRM notes that when multiple violations are under examination and a monetary penalty is imposed for some but not all of them, a Letter 3800 will not be issued for the violations that are not penalised. In other words, a warning letter is generally a whole-case outcome for the relevant years, not a consolation note attached to a penalty.

The FBAR procedures chapter, IRM 4.26.17 at https://www.irs.gov/irm/part4/irm_04-026-017r, adds that Letter 3800 needs group manager and FBAR coordinator concurrence, and is not issued where a single willful penalty covers several years.

Non-willful vs willful: which side of the line are you on?

A warning letter is realistically available only where the facts point to a non-willful violation, ideally one with reasonable cause. The distinction drives everything else.

A non-willful violation is, in practice, any FBAR failure that is not willful. Under IRM 4.26.16.5.4, the penalty for a non-willful violation should not be imposed if the violation was due to reasonable cause and accurate delinquent or amended FBARs are filed to rectify the prior violation. Where reasonable cause is not established, the statutory maximum is $10,000 per violation, adjusted annually for inflation under 31 CFR 1010.821, and the IRM caps the total of non-willful penalties across all open years at 50 percent of the highest aggregate balance of the accounts involved. Since the Supreme Court's decision in Bittner, the non-willful penalty applies per report rather than per account; we cover that rule in a separate article.

A willful violation is far more serious. IRM 4.26.16.5.5 sets the maximum at the greater of $100,000, adjusted for inflation, or 50 percent of the balance in the account at the time of the violation. The IRM says willfulness can be shown by a knowing violation, by reckless disregard of the requirements, or by willful blindness, meaning a conscious effort to avoid learning about the reporting rules. The manual specifically identifies ticking the wrong box, or no box, on the foreign accounts question in Schedule B of Form 1040 as a significant fact to weigh.

Reasonable cause, as the courts cited in the IRM describe it, exists where a person committed the violation despite exercising ordinary business care and prudence. For a high-earning professional that standard is demanding, and it usually rests on documented facts, such as reliance on a preparer who was told about the accounts.

What do the FBAR penalty mitigation guidelines require?

The IRS developed mitigation guidelines to help examiners calculate penalties. They sit in Exhibit 4.26.16-2 of the IRM. To qualify, the filer must meet four criteria, summarised below:

No history of criminal tax or Bank Secrecy Act convictions for the preceding 10 years, and no history of prior FBAR penalty assessments.
No money passing through any of the foreign accounts was from an illegal source or used to further a criminal purpose.
The filer cooperated during the examination, for example the IRS did not have to resort to a summons, the filer responded to reasonable requests for documents, meetings and interviews, and the filer back-filed correct reports.
The IRS did not determine a civil fraud penalty for an underpayment in the year in question due to failure to report income related to a foreign account.

In the current manual, the mitigation table itself is framed for willful violations. For non-willful cases, the IRM directs examiners to recommend, in most cases, one penalty per violation at or below the statutory maximum. Either way, cooperation and prompt back-filing are the behaviours that make a warning letter possible in the first place.

What triggers an FBAR examination for a UK resident?

FBAR examinations can arise in two ways. According to the IRM, some start from an income tax examination of your Form 1040; others are opened directly as Bank Secrecy Act examinations without any tax audit.

Information flow is the background driver. The IRS explains at https://www.irs.gov/businesses/corporations/foreign-account-tax-compliance-act-fatca that FATCA requires foreign financial institutions to report on the foreign assets held by their US account holders. The UK implements this through an intergovernmental agreement under which UK institutions report to HMRC, which passes the information to the IRS. GOV.UK's account holder guidance at https://www.gov.uk/government/publications/exchange-of-information-account-holders explains that banks, building societies, insurers and investment firms may ask customers for information because international agreements allow tax authorities to share data about a wide range of financial accounts and investments.

The triggers we see for UK-based clients include a Form 1040 with foreign income but no FBAR on record, a Schedule B foreign account question answered no, and a Form 8938 filed without a matching FBAR. The IRS does not publish its selection criteria, but each is a mismatch an examiner can see.

Missed FBAR warning letter: what it means and what it does not mean

Clients who receive Letter 3800 often read it as a clean bill of health. It is better understood as a conditional reprieve. According to IRM 4.26.17, the letter sets out the violation and the examiner's recommendations, which may include timely filing accurate FBARs and maintaining required records, with a written summary attached. It gives the recipient 30 days to respond, and the IRM states that issuing Letter 3800 is not a case closing action by itself; it leads to the filer admitting or correcting the errors.

What a warning letter means:

The examiner found an FBAR violation but decided that no monetary penalty is warranted for the years covered.
You are expected to file accurate delinquent or corrected FBARs as instructed, and the examiner will confirm the electronic filing before closing the case.
Future compliance is expected. The letter puts you on formal notice of the reporting and recordkeeping requirements.

What a warning letter does not mean:

It is not a closing agreement on your income tax. Any Title 26 examination of your Form 1040, Form 8938 or other information returns runs on its own track and can still produce adjustments and penalties.
It is not final if you ignore it. The IRM says that if delinquent or corrected FBARs are not filed or are inaccurate, the examiner should consider penalties for the continued failure.
It does not protect later years. The IRM's willfulness guidance includes an example in which a person who received a warning letter fails to file an FBAR in a subsequent year; if the explanation does not outweigh the evidence, the willful penalty should apply.

That last point is the gap almost nobody discusses. A warning letter converts ignorance into knowledge. After it, the IRS holds a document showing you were told, and any later miss is measured against that record. We treat the year after a warning letter as the most important compliance year a client will have.

How should you respond to Letter 3800 within the 30 days?

The IRM describes three possible positions at the 30-day point. If agreement to the violations is received before the deadline, the examiner proceeds to close; agreement may be verbal or written and is documented in the examination record. If written disagreement is provided by the deadline, the examiner considers it. If nothing is received, the examiner consults the group manager on the proper disposition.

Our practical sequence for UK-based clients is as follows. First, reconcile every account for every year in the letter, including accounts you consider minor: joint accounts, a spouse's account you can sign on, old savings accounts, ISAs, share plan accounts, pensions where reportable, and any company account where you hold signature authority. Second, convert each maximum balance to US dollars using the Treasury year-end rate published at https://fiscaldata.treasury.gov, applied consistently. Third, file the delinquent or amended FBARs through the BSA E-Filing System at https://bsaefiling.fincen.treas.gov/main.html exactly as the letter instructs. Fourth, send confirmation of filing to the examiner within the window, with a short covering explanation that matches the facts you gave during the examination.

On the late filing itself, IRM 4.26.16.3.11 explains that page one of FinCEN Form 114 should detail the reason the FBAR was not filed on time, selected from a drop-down box, and that the Other option provides a text box of up to 750 characters. Keep the explanation factual and consistent. An explanation that contradicts what you told the examiner is worse than a brief one.

If you disagree with the violation as described, for example because an account was below the threshold, say so in writing before the deadline. Do not let the window lapse in silence.

Warning letter vs Form 13449: what is the difference?

If the examiner decides a penalty is warranted, the document you will see is not Letter 3800 but Form 13449, Agreement to Assessment and Collection of Penalties Under 31 U.S.C. 5321(a)(5) and 5321(a)(6). The IRM describes Form 13449 as both an agreement and the examiner's report of FBAR violations, and as the basis for the penalty assessment. For non-willful reporting violations, the IRM directs examiners to prepare one form per calendar year.

Signing Form 13449 means agreeing to the assessment; declining leads down the unagreed route, which can include an Appeals protest. Separate articles on our site cover CP15 penalty notices and collection, so we do not repeat them here.

How long can the IRS assess an FBAR penalty?

The statute of limitations on assessing civil FBAR penalties is six years from the date of the violation, under 31 USC 5321(b)(1), as the IRM confirms. For calendar years 2016 onward, the IRM treats the violation date as 15 April of the following year where a complete and accurate FBAR has not been filed by the automatic extended due date of 15 October. A recordkeeping violation is dated from when the examiner first requests the records by summons.

Two features of this statute catch high-net-worth clients out. First, it runs independently of the income tax statute; the IRM states that a consent to extend the statute for a Title 26 examination does not extend the FBAR statute. Second, the IRM says that other than a filer's consent to extend, there are no statutory exceptions, including fraud or willfulness. When the statute is close to expiring, examiners are directed to solicit a separate FBAR consent, and whether to sign it is a decision with real consequences.

Why does getting compliant before IRS contact matter so much?

The single most valuable fact in this area: the IRS Streamlined Filing Compliance Procedures page at https://www.irs.gov/individuals/international-taxpayers/streamlined-filing-compliance-procedures states that if the IRS has initiated a civil examination of a taxpayer's returns for any taxable year, regardless of whether the examination relates to undisclosed foreign financial assets, the taxpayer will not be eligible to use the streamlined procedures. The same applies to anyone under criminal investigation.

For an American resident in the UK, the Streamlined Foreign Offshore Procedures are typically the best route. According to https://www.irs.gov/individuals/international-taxpayers/us-taxpayers-residing-outside-the-united-states, eligible taxpayers file three years of delinquent or amended tax returns and six years of delinquent FBARs, certify non-willful conduct, and are not subject to failure-to-file, failure-to-pay, accuracy-related, information return or FBAR penalties. US citizens qualify on the non-residency test if, in any one of the three most recent years, they had no US abode and were physically outside the United States for at least 330 full days. The IRS defines non-willful conduct as conduct due to negligence, inadvertence or mistake, or a good faith misunderstanding of the law.

Compare that with the examination path, where the best outcome is a warning letter that depends on examiner discretion and manager concurrence. The 5 percent miscellaneous offshore penalty applies only under the Streamlined Domestic Offshore Procedures, not the foreign version. Streamlined submissions do not culminate in a closing agreement and may still be selected for audit under normal processes.

For readers whose only gap is the FBAR itself, with income fully reported and US tax paid, a late FBAR can be filed through the BSA E-Filing System with a reason for late filing. The IRS withdrew its former standalone late-FBAR page around July 2026, so do not rely on it as a named programme.

What about HMRC and the UK side of the same accounts?

A US enquiry into UK accounts rarely raises a UK problem, because most UK-based Americans have paid UK tax on UK income. The exception is income or accounts outside the UK, such as a US brokerage account held by a UK resident, which HMRC treats as an offshore matter.

HMRC's route for correcting offshore matters is the Worldwide Disclosure Facility, described at https://www.gov.uk/guidance/worldwide-disclosure-facility-make-a-disclosure and HMRC states that it covers unpaid or omitted UK tax relating to income from a source outside the UK, assets held outside the UK, or activities carried on wholly or mainly outside the UK. The process starts with notifying HMRC through the Digital Disclosure Service, after which you have 90 days to complete the disclosure, and payment is due on the date the disclosure is submitted. HMRC also notes that tougher sanctions under the Requirement to Correct rules took effect on 1 October 2018 for offshore non-compliance.

Worked scenario: a London-based American and a missed FBAR

The following is an illustration with assumed figures, not a real client. Assume an exchange rate of 1 GBP = 1.30 USD for every year. Emma is a US citizen and investment banker in London with a UK current account, a cash ISA and a UK brokerage account. Her combined maximum balances over four years ranged from 180,000 GBP to 260,000 GBP, about 234,000 USD to 338,000 USD on the assumed rate. She filed Form 1040 each year with a preparer, reported all UK salary and interest, and owed no US tax after foreign tax credits, but never filed an FBAR, and one return answered the Schedule B foreign accounts question incorrectly because her preparer never asked.

Path one, before contact. Emma meets the 330-day test, has no examination open, and her facts support a non-willful certification. She files three years of amended returns where needed, six years of FBARs through BSA E-Filing with Streamlined Filing Compliance Procedures entered as the reason, and the Streamlined Foreign certification. Under the published procedures, no penalty applies.

Path two, after contact. Instead, the IRS opens an examination of her Form 1040 for a later year, and the examiner identifies the missing FBARs. Streamlined is now closed to her. Emma cooperates fully, provides statements promptly, and documents that her preparer never asked about foreign accounts. The examiner weighs the discretion factors: no prior warnings, full income reporting, cooperation, and balances that are significant but fully taxed. The examiner, with manager and coordinator concurrence, issues Letter 3800. Emma files the delinquent FBARs within 30 days, the examiner confirms them, and the case closes with no FBAR penalty.

Path one rested on published procedure; path two rested on discretion that could have gone the other way. And after path two, Emma's next missed FBAR would be judged against a warning letter on file.

Missed FBAR checklist for UK-based Americans

List every foreign account for the last six years, including ISAs, joint accounts, share plan accounts and any account where you hold signature authority.
Find the maximum balance for each account each year and convert it using the Treasury year-end rate.
Check whether any Form 1040 answered the Schedule B foreign account question incorrectly.
If no IRS examination is open, assess Streamlined Foreign eligibility, including the 330-day test and a non-willful narrative you can document.
If only FBARs are missing and all income was reported, consider filing late through BSA E-Filing with a factual reason.
If you have received Letter 3800, diarise the 30-day deadline and file accurate FBARs exactly as instructed.
Keep the records the FBAR rules require for five years from each due date: account name, number, institution, type and maximum value.
Check the UK position on any non-UK accounts or income and consider whether a Worldwide Disclosure Facility notification is needed.
File every future FBAR on time; after a warning letter, a later miss can be treated as willful.

Next steps if you have a missed FBAR

If no examination is open, the Streamlined Foreign Offshore Procedures remain the cleanest way to put a missed FBAR behind you. If you are already under examination, cooperation, accurate back-filing and a documented reasonable cause narrative give the examiner grounds to close with a warning letter. Our team prepares FBARs, Streamlined submissions and examination responses for Americans across the UK.