NISA, specified and general taxable accounts, iDeCo, corporate pensions, deposits, JGBs, and how they can combine.
NISA shelters qualifying gains from Japanese tax; taxable "specified" and "general" accounts hold everything else with different reporting; iDeCo and corporate pensions lock money for retirement in exchange for tax benefits. Most of these can be held at the same time.
NISA is a tax wrapper: qualifying gains, dividends, and distributions are exempt from Japanese tax, with a ¥1.2m recurring allowance plus ¥2.4m growth allowance each year and an ¥18m lifetime acquisition-cost limit. Its trade-off is that NISA losses cannot offset taxable gains or be carried forward, and the product menu is limited.
Taxable accounts come in three forms. A specified account with withholding (特定口座・源泉徴収あり) has the broker calculate gains and withhold Japanese tax, so a return is often unnecessary. A specified account without withholding gives you an annual report but you normally file yourself. A general account (一般口座) requires you to calculate acquisition cost and taxable gain — the highest recordkeeping burden, used for assets the specified account cannot hold.
iDeCo is a private defined-contribution pension: contributions are generally fully deductible from income, growth is tax-deferred, and retirement or pension deductions may apply on receipt — but the money is generally locked until eligible retirement age, minimum contributions are normally ¥5,000/month, and limits depend on employment and employer-pension coverage. Corporate DC and defined-benefit plans add employer funding and payroll integration, with employer-selected menus and withdrawal restrictions. (Scheduled changes from December 2026 broaden some iDeCo limits — verify current figures when enrolling.)
Alongside these sit cash tools: ordinary and time deposits (insured up to ¥10m principal per bank), retail JGBs (government-backed, ¥10,000 minimum, monthly issue, early-redemption adjustment), and foreign-brokerage or robo-advisor accounts. Each has a role; none replaces an emergency fund.
Most of these coexist. A common structure is: an emergency fund in deposits; NISA funded first for flexible tax-free growth; iDeCo added when the contribution deduction is valuable and lock-up acceptable; and a taxable specified account for anything beyond NISA limits, ineligible assets, loss-sensitive strategies, or active trading. NISA itself must be held at one eligible Japanese institution.
Think in terms of asset location: put assets you expect to grow long-term inside NISA to use the tax-free space efficiently, and place overflow, ineligible, or loss-harvesting positions in the taxable account where loss offsets are available.
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.
They solve different problems. NISA is flexible: tax-free growth and you can withdraw anytime, making it the usual first choice. iDeCo gives a larger up-front tax break (contributions cut your taxable income) but locks money until age 60 and suits committed retirement saving. Many use NISA first for flexibility, then add iDeCo for the deduction if they are confident they will not need the money before 60. If you may leave Japan, iDeCo’s lock-up is a bigger drawback.
Generally yes, if you are a tax resident of Japan (with a My Number) and at least 18. NISA is tied to residency, not citizenship, so most foreign residents qualify — with two big cautions: US citizens and green-card holders face US tax complications with Japanese funds, and NISA generally cannot continue after you leave Japan. Confirm eligibility and the current rules on the FSA site and with your chosen brokerage.