FBAR vs Form 8938: Which Foreign Account Forms Do You Need?

The short answer: the FBAR applies once your non-US accounts together top $10,000 at any point in the year, Form 8938 kicks in at much higher thresholds, and most Americans in the UK who cross both need to file both. The two forms cover overlapping but not identical ground, they go to different agencies, and neither one satisfies the other. Filing one and skipping the other is one of the most common reporting mistakes we see, and the penalties attach to the missing form, not to any tax owed.

What is the FBAR and who has to file it?

The FBAR, formally FinCEN Form 114, is a bank secrecy filing, not a tax form. It goes to FinCEN, the Treasury's financial crimes network, not to the IRS, and it is filed electronically on its own, separate from your tax return.

You file it if the combined value of your non-US financial accounts exceeded $10,000 at any point in the year, even for a single day. The threshold is aggregate, so five accounts holding £2,000 each will cross it. It also covers accounts you do not own but have signature authority over, such as an employer's account you can sign on or a parent's account you help manage. The FBAR is due April 15 with an automatic extension to October 15, with no request needed. If this is your first year over the threshold, our guide to filing an FBAR for the first time sets out what to gather before you open the form.

What is Form 8938 and who has to file it?

Form 8938 is the FATCA reporting form, and unlike the FBAR it is a tax form: it is filed with your Form 1040 and goes to the IRS. It covers "specified foreign financial assets," a broader category than accounts, but its thresholds are far higher, and they are more generous for Americans actually living abroad:

• Single or married filing separately, living abroad: $200,000 in total assets at year end, or $300,000 at any point in the year.
• Married filing jointly, living abroad: $400,000 at year end, or $600,000 at any point in the year.
• Living in the US: much lower thresholds, starting at $50,000 at year end for a single filer.

Many Americans in the UK sit below the 8938 thresholds for years and then cross them in a single step, typically when a pension pot grows, a property sale lands in a UK account, or vested employer shares accumulate. That first crossing year is when the form gets missed. Because Form 8938 travels with the 1040, it shares the return's deadlines: June 15 for Americans abroad, extendable to October 15, and it simply is not filed at all in a year when no return is required. Every threshold by filing status and residence is set out in our Form 8938 vs FBAR threshold table.

What does each form catch that the other misses?

The overlap is large: ordinary UK bank accounts, ISAs, and most pensions appear on both forms once you are over both thresholds. But each form reaches things the other does not:

• Form 8938 catches, FBAR misses: foreign stock or securities held directly rather than through an account, interests in foreign entities such as a UK limited company or partnership, and foreign financial instruments with a non-US counterparty.
• FBAR catches, Form 8938 misses: accounts you merely have signature authority over without any ownership interest, which Form 8938 excludes.

This is why the practical answer for most established expats is simply both. The forms cross-check each other, and both cross-check the income on the return itself: an account reported on the FBAR with interest income missing from the 1040 is exactly the pattern that draws attention. Our foreign income and FBAR service prepares the two forms and the return from a single set of account data so nothing falls between them.

What counts as a reportable account in the UK?

More than most people expect. For an American in the UK, the reportable list typically includes:

• Current and savings accounts, including joint accounts with a non-US spouse.
• Cash ISAs and stocks and shares ISAs. The ISA wrapper means nothing to the US, and the funds inside a stocks and shares ISA are usually PFICs on top, a separate problem handled by our PFIC reporting service.
• NS&I Premium Bonds, which are an account with a government institution despite the name.
• Workplace pensions and SIPPs, which most practitioners include on both forms. See our guidance on US/UK pensions for how the underlying tax treatment works.

How do you value accounts and handle joint ones?

Both forms want the maximum value of each account during the year, not the year-end balance, converted to US dollars. In practice you take the highest balance shown on the year's statements and convert it using the Treasury's year-end exchange rate. Precision is not the point; the forms accept reasonable approximations, and periodic statements are an acceptable basis. What is not acceptable is leaving an account off because its peak balance is hard to pin down.

Joint accounts follow the person, not the money. A joint current account with a non-US spouse goes on the American spouse's FBAR at its full value, not half, even though the non-US spouse has no US filing obligation at all. The same account also counts in full toward the Form 8938 thresholds for a married-filing-separately filer. This is one of the quieter reasons filing status matters so much for Americans married to Brits, and it is part of the analysis in our US tax return service.

How bad are the penalties really?

Serious, and they do not depend on owing any tax:

• FBAR, non-willful: up to $10,000 per violation, indexed for inflation. The Supreme Court's Bittner decision confirmed the penalty applies per unfiled report, not per account, which capped the worst outcomes.
• FBAR, willful: the greater of $100,000 or 50% of the account balance, per year, with criminal referral possible in egregious cases.
• Form 8938: $10,000 for failure to file, rising by $10,000 increments to a maximum of $50,000 if the failure continues after IRS notice, plus an extended statute of limitations on the whole return.

In practice, penalties at these levels are the exception rather than the rule for people who come forward voluntarily. They exist to punish concealment, and the IRS routes genuine oversight cases into the fix-it programs below.

What if you are behind on either form?

The right route depends on whether tax was underpaid:

1. All income was reported, only the forms are missing: you file the late forms promptly, with an explanation for a late FBAR and a reasonable cause statement for a late Form 8938. The IRS withdrew its Delinquent FBAR Submission Procedures page in July 2026, and its FBAR page now says a late FBAR is a violation that may be penalized depending on facts and circumstances, so this route no longer comes with a written no-penalty statement.
2. Income was also missed: the Streamlined Foreign Offshore Procedures are normally the answer for those living abroad: three years of amended or original returns, six years of FBARs, and a certification that the failure was non-willful, with penalties waived.

Both routes close once the IRS makes contact first, so the cost of waiting is the loss of the cheap fix. This applies just as much to accidental Americans who never knew they had US obligations as it does to long-term expats who let filings lapse.

The bottom line

Treat the two forms as a pair. Check the $10,000 FBAR threshold first, because almost everyone with a UK financial life crosses it, then check the 8938 thresholds for your filing status. When in doubt, report: there is no penalty for including an account that was arguably not required, and a five-figure penalty for the reverse.

If you are appointing someone to handle this for you, make sure the engagement covers the reporting forms and not just the return — our nine questions to ask when choosing US/UK cross border tax specialists covers what to confirm in writing first.

Official sources

The rules described here come from the tax authorities themselves. Thresholds and procedures change, so check the current guidance before you file:

• IRS: Comparison of Form 8938 and FBAR requirements
• FinCEN: BSA E-Filing System (where the FBAR is filed)