Best Portfolio Tracker for Japan Investors

One dashboard for your NISA, iDeCo, and international holdings — built for Japan-based investors navigating a weak yen and global markets.

Why tracking investments in Japan is different

Japan is the world's third-largest economy, and its investment landscape has been transformed in recent years. The expansion of NISA (Nippon Individual Savings Account) in 2024 dramatically increased tax-free investment limits, triggering a wave of new retail participation. Japanese investors poured record amounts into global equity funds, particularly US-focused index funds tracking the S&P 500 and all-country world indices. Combined with the yen's historic weakness — falling from 110 to over 150 per US dollar between 2021 and 2024 — international holdings have seen extraordinary gains when measured in JPY terms, even in periods where underlying markets were relatively flat.

For both Japanese nationals and the growing community of foreign residents, investing from Japan presents distinct challenges. The domestic brokerage ecosystem is dominated by SBI Securities and Rakuten Securities, both offering comprehensive but Japanese-language platforms that can be difficult for English-speaking expats to navigate. Tax reporting for foreign residents is complex, with obligations varying based on residency length and visa status. Holdings are often scattered across a NISA account, an iDeCo pension, a regular taxable brokerage, and potentially accounts in a home country — each with different tax treatment, different currencies, and no unified view.

FlashFi gives Japan-based investors a single English-language dashboard that tracks portfolios in JPY alongside USD, EUR, GBP, and 30+ other currencies. Whether you hold a NISA account with SBI Securities, an iDeCo pension with Monex, and US equities through Interactive Brokers, FlashFi consolidates everything with real-time currency conversion so you always know your true net worth in yen.

Key challenges for Japan investors

Yen weakness amplifies currency exposure

The Japanese yen has depreciated dramatically against major currencies since 2021, driven by the Bank of Japan's yield curve control policy and interest rate differentials with the US and Europe. For Japan-based investors holding USD or EUR-denominated assets, this has produced significant windfall gains in yen terms. But it also means that any future yen recovery could substantially reduce the JPY value of foreign holdings. Most Japanese brokerages display international fund NAVs in yen without separating asset performance from currency impact, making it difficult to understand your true exposure.

NISA and iDeCo sit in separate silos

The expanded NISA program offers a lifetime tax-free investment limit of 18 million yen, with an annual contribution cap split between the Tsumitate (savings) and Growth investment buckets. iDeCo provides additional tax-advantaged retirement savings with contribution deductions from taxable income. But NISA, iDeCo, and regular taxable accounts each sit with their own provider and portal. An investor with NISA at SBI, iDeCo at Monex, and a taxable account at Rakuten has three separate dashboards and no consolidated net worth figure.

Language barrier for foreign residents

Japan has a growing population of English-speaking foreign residents — professionals, educators, and entrepreneurs living on work visas and permanent residency. Most Japanese brokerages operate primarily in Japanese, with limited English interfaces. SBI Securities and Rakuten Securities have made improvements, but account opening, tax reporting, and customer support remain challenging for non-Japanese speakers. Interactive Brokers Japan offers a full English experience but does not support NISA accounts, forcing expats to maintain at least two separate brokerages.

Complex tax rules for foreign residents

Japan taxes investment income for residents, but the rules differ based on residency status. Permanent residents are taxed on worldwide income. Non-permanent residents — those who have lived in Japan for fewer than five of the past ten years — are only taxed on Japan-sourced income and foreign income remitted to Japan. This distinction is critical for expats with overseas investment accounts, as the treatment of capital gains and dividends from foreign brokerages depends on whether proceeds are transferred to a Japanese bank account.

How FlashFi helps Japan investors

JPY-Native Dashboard

View your entire portfolio in Japanese yen with automatic real-time conversion from USD, EUR, GBP, and 30+ other currencies. FlashFi shows the true yen value of your global holdings so you always know your net worth in JPY.

Track NISA and iDeCo Alongside Everything Else

Add your NISA holdings, iDeCo balance, taxable brokerage accounts, and international investments into a single dashboard. See your total net worth and asset allocation across all accounts at a glance.

English-Language Interface

FlashFi is fully English-language, providing Japan-based expats and international investors with a portfolio tracker that does not require navigating Japanese-language brokerage portals to understand their total financial position.

Real-Time FX Impact

See exactly how JPY/USD and JPY/EUR movements affect the yen value of your international holdings. FlashFi separates asset performance from currency impact so you know whether your S&P 500 fund gained because the market went up or because the yen went down.

Frequently asked questions

Can I track my NISA account in FlashFi?

Yes. You can add your NISA holdings as a separate portfolio in FlashFi, whether you use SBI Securities, Rakuten Securities, or any other NISA provider. Your NISA balance is included in your total net worth alongside taxable accounts, iDeCo, and international holdings.

Does FlashFi show my portfolio in JPY?

Yes. Set JPY as your base currency and FlashFi converts all holdings to Japanese yen using live exchange rates. If you hold US stocks, European ETFs, or assets in other currencies, you will see their current yen value updated with real-time FX data.

Is FlashFi available in English for Japan-based users?

Yes. FlashFi is a fully English-language platform that works from any country. If you are an expat or foreign resident in Japan who finds Japanese brokerage interfaces difficult to navigate, FlashFi gives you a clear English dashboard to track all your holdings in one place.

How does yen weakness affect my international holdings in FlashFi?

FlashFi shows the real-time yen value of all your holdings, so when JPY weakens against USD or EUR, you will see the JPY value of your international positions increase accordingly. The FX impact feature separates currency movement from underlying asset performance, so you can see exactly how much of your return in yen terms came from the market versus the exchange rate.

Can I track my home-country investments alongside my Japanese accounts?

Absolutely. FlashFi supports 30+ currencies and works with any brokerage worldwide. Whether you have a 401(k) in the US, a Stocks and Shares ISA in the UK, or a super fund in Australia, you can track it alongside your NISA and Japanese brokerage accounts in a single dashboard.

By David Brougham