Investment Tax Basics - When You Need to File and How to Save on Taxes

Tax Rate on Investment Profits

Capital gains from stocks and mutual funds, as well as dividends and distributions, are taxed at a flat rate of 20.315% in Japan (15.315% income tax + 5% resident tax). For example, on a profit of 100 man-yen, roughly 20 man-yen goes to taxes, leaving about 80 man-yen in hand. This rate applies regardless of the size of the profit and is calculated separately from employment income under the separate self-assessment taxation system (Shinkoku Bunri Kazei).

For more detail, investment tax filing guides clarify the differences between specific accounts and general accounts, and when filing is required.

If you use a Tokutei Koza (specific account) with withholding, your brokerage automatically calculates and deducts taxes, so in principle no tax return is needed. However, filing becomes necessary if you trade across multiple brokerages or want to carry forward losses to future years.

Tax-Loss Offsetting and Loss Carryforward

If you have both gains and losses in the same year, you can offset gains with losses through Soneki Tsusan (tax-loss offsetting). For example, if Stock A produced a 50 man-yen gain and Stock B a 30 man-yen loss, the taxable amount is only 20 man-yen. To offset gains and losses across different brokerages, you must file a tax return.

If your total losses exceed gains for the year, you can carry forward the net loss for up to three years by filing a tax return. When you earn profits in subsequent years, the carried-forward loss can be used to offset those gains, reducing your tax burden. To claim this carryforward, you must file consecutively every year starting from the year the loss occurred.

Maximizing the Tax-Free Benefits of NISA

Profits earned in a NISA account are completely tax-free. Within the annual investment limits (120 man-yen in the Tsumitate frame + 240 man-yen in the Growth frame), capital gains and dividends from purchased financial products are exempt from taxation. The impact of eliminating the 20.315% tax is substantial - for instance, on 1,000 man-yen of profit over 30 years, the tax savings amount to roughly 203 man-yen.

When starting to invest, prioritize filling your NISA allowance first. For investments beyond the NISA limit, use a specific account with withholding to minimize the hassle of tax filing.

books on tax-loss offsetting strategies explain how to combine gains and losses across multiple accounts to reduce your overall tax burden.