Foreign financial accounts, the FBAR aggregate threshold, how Form 8938 differs, NISA/brokerage inclusion, and that filing is not the same as owing tax.
A US person must file an FBAR when aggregate foreign financial accounts exceed US$10,000 at any point in the year, and separately may need Form 8938 under different thresholds; Japanese bank, brokerage, and NISA accounts can count, and filing does not by itself mean tax is due.
The FBAR (Report of Foreign Bank and Financial Accounts, FinCEN Report 114) is an information report, separate from your income tax return. A US person must file it when the aggregate value of their foreign financial accounts exceeds US$10,000 at any point during the calendar year — note that it is the combined peak across all accounts, not per account. Japanese bank accounts, brokerage accounts, and certain fund accounts, including NISA, can be included.
Because the threshold is an aggregate and uses the highest balance during the year, it is easy to cross without realising: a few ordinary Japanese accounts can total over US$10,000 at some point. You report the maximum value of each account during the year.
Form 8938 (Statement of Specified Foreign Financial Assets) is a separate FATCA filing attached to your income tax return, with different definitions and thresholds — which are generally higher than FBAR’s and vary by filing status and whether you live abroad. It covers "specified foreign financial assets," which can include foreign accounts and certain foreign investments.
The key point is that FBAR and Form 8938 are two different obligations: filing one does not satisfy the other, and depending on your balances you may need to file both, neither, or one. They ask overlapping but not identical questions, which is why people often file both.
A crucial reassurance: these are information reports, not tax bills. Filing an FBAR or Form 8938 discloses that you hold foreign accounts; it does not by itself create a tax liability. Whether you owe US tax depends on your income (dividends, gains, PFIC consequences), not on the disclosure forms themselves.
That said, the penalties for failing to file these reports when required can be severe, so the reporting matters even though it is not a tax. If you are a US person with Japanese accounts, treat FBAR and Form 8938 as a compliance checklist to review each year, and get professional help to determine exactly which apply to you.
Brokerage (NISA/iDeCo) · Rakuten Securities
A leading low-cost brokerage for NISA and index-fund investing, integrated with Rakuten points and Rakuten Bank.
Fees: Many domestic funds and trades are low- or no-commission — verify current fee schedule.
Brokerage (NISA/iDeCo) · SBI Securities
Japan’s largest online brokerage by accounts, with a very broad low-cost fund lineup and full NISA/iDeCo support.
Fees: Many trades and funds are low- or no-commission — verify current fee schedule.
Brokerage (NISA/iDeCo) · Monex
An established online brokerage often chosen for US-stock access and research tools, with NISA and iDeCo support.
Fees: Commissions vary by product; some funds/trades are low-cost — verify current schedule.
Be very careful. Japanese mutual funds and ETFs are usually PFICs (Passive Foreign Investment Companies) for US tax, which triggers punitive US taxation and heavy Form 8621 reporting — and the NISA tax exemption does not apply to the US. Many US persons in Japan avoid Japanese pooled funds and instead hold US-domiciled assets, but rules are complex. Get advice from a cross-border US/Japan tax professional before investing.