Why NISA is not a US exemption, the PFIC problem with Japanese funds, FBAR and Form 8938, and a practical order of operations.
US citizens and resident aliens are taxed on worldwide income, so NISA gives no US exemption, and popular Japanese mutual funds can trigger punitive PFIC rules and Form 8621; NISA and brokerage accounts may also be reportable on FBAR and Form 8938. Get cross-border advice before buying a Japanese fund.
A US citizen or resident alien generally reports worldwide income to the United States even while living in Japan. NISA is a Japanese statutory exemption, not a provision of the US Internal Revenue Code, so dividends, gains, and distributions inside NISA can still be reportable and taxable in the US. US reporting can apply whether or not you withdraw the money, and the foreign earned income exclusion generally covers earned income, not ordinary investment income.
This does not automatically make NISA worthless for a US person — it can still remove Japanese tax — but its US treatment depends heavily on what you hold inside it, which is where the real complications begin.
A Japanese-domiciled mutual fund can be a Passive Foreign Investment Company (PFIC) because it is a foreign corporation earning mostly passive income or holding passive assets. A US shareholder may need a separate Form 8621 for each such fund, and punitive "excess distribution" taxation or complex elections can apply. Not every foreign investment is a PFIC — operating-company shares generally are not — but popular Japanese index funds should be presumed to require analysis rather than presumed safe.
A Japan-listed ETF has no universal answer either; many non-US fund vehicles warrant PFIC analysis. The practical consequence is that buying a low-cost Japanese mutual fund — the standard beginner move — can be exactly the wrong first step for a US person without advice.
Two reporting regimes commonly apply. FBAR (FinCEN Report 114) is required when a US person’s aggregate foreign financial accounts exceed US$10,000 at any time in the year; Japanese bank, brokerage, and certain fund accounts, including NISA, can count. Form 8938 is a separate FATCA filing with different thresholds and definitions — filing one does not replace the other, and filing does not by itself mean tax is due.
A practical US-person hierarchy: (1) confirm the broker accepts US persons — some, such as Rakuten, restrict foreign-stock trading for them; (2) do not buy a Japanese mutual fund until PFIC treatment is reviewed; (3) consider whether permitted US-domiciled ETFs or individual securities are simpler and appropriate; (4) review Japan tax, US tax, foreign tax credits, withholding, FBAR, Form 8938, estate tax, and state residence; (5) keep statements in both yen and US-dollar terms. The safest first step is a cross-border product and reporting review before buying anything.
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.