Is NISA Really a Cure-All? Financial Income Taxation and Inheritance Explained Neutrally

October 19, 2026

Taiga Sato

*Amounts and rules are as of July 2026. This article is an English version of our Japanese guide, adapted for foreign residents of Japan and international investors. It is a general explanation based on published information; because decisions on NISA, stock investment, inheritance tax and income tax depend on individual circumstances, please check actual investment and tax decisions with a securities company, a certified tax accountant or another professional.

The new NISA (Nippon Individual Savings Account) started in 2024, and building wealth through stocks and investment trusts has become more accessible than before. Normally, about 20% tax is charged on gains from selling listed shares and on dividends, but investment gains earned within a NISA account are tax-free. The lifetime tax-free holding limit has also been expanded to JPY 18 million, making it a very attractive scheme for people thinking about long-term investment.

On the other hand, rather than simply assuming that NISA is "a scheme that always pays off if you use it", it is important to use it with an understanding of its assumptions and its exit. In particular, the debate on taxation of financial income, how NISA is treated when an inheritance occurs, and how it relates to investing in later life are points that the longer you invest in stocks, the more you should check.

The basic advantages of NISA

The biggest advantage of NISA is that investment gains are tax-free. When you sell shares or investment trusts at a profit in an ordinary taxable account, you are in principle charged income tax, special reconstruction income tax and inhabitant tax combined. By contrast, gains on sale and certain dividends and distributions from products held in a NISA account are tax-free.

However, losses incurred in a NISA account are treated for tax purposes as if they "did not exist". In an ordinary taxable account, you may be able to offset capital losses on listed shares against other gains or, under certain conditions, carry them forward to following years. With NISA, however, such offsetting and loss carry-forward are not available. NISA is strong when you make a profit, but tax relief when you make a loss is limited.

The debate on taxation of financial income and NISA

One major issue that is often raised is the relationship with taxation of financial income. In Japan, capital gains and dividends on listed shares are often taxed under separate self-assessment taxation at a rate of about 20%, which is different from the progressive taxation applied to employment income and other income.

This system is meant to promote investment and support household wealth building. On the other hand, the higher a person's income, the larger the share of financial income tends to be, and some argue that it should be reviewed from the standpoint of fairness in the tax burden.

What matters here is not to conclude that "because NISA exists, taxation of financial income will definitely be tightened". Tax reforms are decided in light of politics, the economy, household support and the impact on markets, and cannot be explained by a single factor. Still, as long as the debate on taxation of financial income may continue, you should assume that current tax rates and rules will not necessarily stay the same in the future.

How a NISA account is treated on inheritance

One aspect of NISA that is easily overlooked is how it is treated on inheritance. When a person with a NISA account dies, the products in that NISA account are not carried over as they are into the heir's NISA account. In principle, they are transferred to the heir's taxable account and treated as acquired at an amount equal to their market value at the time of death.

In other words, the tax-free benefit of NISA applies to investment gains up to the time of death, but after inheritance the holdings are treated as being in an ordinary taxable account. If the heir later sells them, the market value at the time of death is used as the acquisition cost, and the difference between that and the sale price becomes taxable.

For example, if shares bought for JPY 1,000 in a NISA account are worth JPY 3,000 at the time of death, the unrealized gain up to the time of death benefits from the NISA tax exemption. If the heir then sells them for JPY 3,000, there is basically no capital gain. On the other hand, if shares had fallen to JPY 500 at the time of death and are sold after recovering to JPY 1,000, the rise from JPY 500 to JPY 1,000 may be treated as a gain for the heir.

In this way, whether NISA looks advantageous or disadvantageous depends on the price at the time of inheritance. NISA is effective for many people, but if you invest a large amount through NISA, or if an elderly relative is using NISA, you should understand the process up to the transfer to a taxable account after inheritance.

Points to watch when investing in later life

In recent years there have been proposals for a NISA scheme for older people and debate over monthly-distribution investment trusts. The wish to use investment trust distributions or regular sales to supplement living expenses after retirement is a natural one.

However, when looking at monthly-distribution products, you need to check what the distributions consist of. Their real meaning differs depending on whether they come from investment gains or include a portion that draws down the principal. You also need to consider costs such as trust fees, price fluctuation risk, longevity risk and the treatment on inheritance.

Points investors should check

When deciding whether to use NISA, start by clarifying your own goals. The suitable account and products differ depending on whether the money is for long-term retirement savings, funds you plan to use in a few years, or assets you intend to pass on through inheritance.

Also, you do not need to think of a NISA account and a taxable account as an either-or choice. One approach is to divide roles: NISA for assets you want to grow over the long term, and a taxable account for assets where you want to manage loss offsetting and the timing of sales flexibly.

In particular, people with large stock investments, business owners, wealthy individuals and those thinking about managing the assets of elderly relatives will have more peace of mind if they check not only tax rates but also inheritance, gifts, exit tax on departure from Japan and the risk of changes to taxation of financial income.

Summary

NISA is a very powerful scheme that supports individuals in building wealth. With the expanded tax-free allowance, its value as a starting point for long-term investment has grown significantly.

On the other hand, NISA also has weaknesses and points to check: losses cannot be offset against gains, holdings are transferred to a taxable account on inheritance, and it cannot stay unaffected by the future debate on taxation of financial income.

What matters is neither to be overly suspicious of NISA nor to treat it as a cure-all. It is to make use of the scheme's advantages while also looking ahead to the exit, inheritance and possible tax changes. The longer you keep investing in stocks, the greater the impact of the "time of sale", the "time of inheritance" and "changes to the rules" compared with the time of purchase. That is why NISA is a scheme to use with the exit, not just the entrance, in mind.