International tax attorney here. FBAR compliance is an area where the penalties for non-filing are disproportionately severe relative to the simplicity of the filing requirement, so I want to provide clear guidance for anyone reading this thread.
You must file FinCEN Form 114 (FBAR) if you had a financial interest in or signature authority over at least one foreign financial account AND the aggregate value of all foreign accounts exceeded 10,000 dollars at any point during the calendar year. This includes bank accounts, brokerage accounts, and mutual funds held at foreign financial institutions. Importantly, cryptocurrency held on foreign exchanges is increasingly being treated as a reportable account, though the Treasury has not issued final guidance on this specific point.
If you have failed to file FBARs in prior years, do not panic, but do act promptly. The IRS Streamlined Filing Compliance Procedures allow taxpayers who were non-willful to file delinquent FBARs and amended tax returns with a reduced penalty structure. For taxpayers living in the US, the penalty is 5 percent of the highest aggregate balance. For those living abroad who qualify, the penalty can be zero. This program has been available for several years and remains open as of 2026, though there is no guarantee it will continue indefinitely.