Is it true that overseas FX is a better deal because it is taxed separately?

“Overseas FX is taxed separately, so apparently you pay little tax even when your profit is large.” Have you heard this in investment videos or on social media?

The part that says “FX is taxed separately at about 20%” is indeed true. However, this rule can be used only for trading on an exchange, or for over-the-counter trading with a registered business operator as the counterparty. If you use an overseas FX operator without registration, the story is reversed. The larger your profit, the higher your tax.

We checked this rumor against the original text of the law and the official information published by the National Tax Agency (NTA).

Four tax terms to know first

Here are plain-language explanations of the terms used in this article.

• FX (foreign exchange margin trading) = Trading in which you buy and sell foreign currency in amounts many times larger than the margin you put up as collateral.
• Separate self-assessment taxation (shinkoku bunri kazei) = A method in which that income alone is separated from your other income and the tax is calculated at a fixed rate.
• Comprehensive taxation (sōgō kazei) = A calculation method in which the income is added to your other income, and the larger the amount, the higher the tax rate. Salary is counted in the same pool.
• Miscellaneous income (zasshotoku) = The category for income that fits none of the other nine types of income, such as salary or business income. Side-job revenue is a typical example.

Conclusion

Our verdict: “False.” Below, we go through the basis in order.

Conditions for FX to qualify for separate taxation

First, let’s check trades made through domestic FX operators (securities companies and FX specialist companies). The NTA’s Tax Answer No.1521 explains which FX qualifies for separate taxation as follows.

金融商品取引法上の「市場デリバティブ取引」または「店頭デリバティブ取引（「第一種金融商品取引業者」または「登録金融機関」を相手方とする取引に限ります。以下同じです。）」に該当する外国為替証拠金取引（FX）の差金等決済（決済または行使もしくは放棄もしくは譲渡の総称です。）により生じた損益の課税関係は、次のとおりです。［2］

Reference translation (unofficial): The tax treatment of gains and losses arising from the settlement of differences, etc. (a general term for settlement, exercise, abandonment or transfer) of foreign exchange margin trading (FX) that falls under a “market derivatives transaction” or an “over-the-counter derivatives transaction (limited to transactions with a ‘Type I financial instruments business operator’ or a ‘registered financial institution’; the same applies below)” under the Financial Instruments and Exchange Act is as follows.

Since this is a stiff passage, here it is in plain terms. FX that qualifies for separate taxation is a “market derivatives transaction” (a trade on an exchange) or an “over-the-counter derivatives transaction” under the Financial Instruments and Exchange Act. For the latter, the counterparty must be a “Type I financial instruments business operator” or a “registered financial institution.” If your counterparty is an FX operator that is registered for financial instruments business in Japan and operates here, this condition is met.

The tax rate in this case is written in Tax Answer No.1522, “Special rules for taxation of miscellaneous income, etc. from futures trading.”

その先物取引に係る事業所得、譲渡所得および雑所得（以下、これらを「先物取引に係る雑所得等の金額」といいます。）については、他の所得と区分して、所得税15パーセント（他に地方税5パーセント）の税率による申告分離課税となります。［3］

Reference translation (unofficial): Business income, capital gains and miscellaneous income from that futures trading (hereinafter referred to as “the amount of miscellaneous income, etc. from futures trading”) are separated from other income and subject to separate self-assessment taxation at an income tax rate of 15% (plus 5% local tax).

No.1521 also has a note on the tax added on top of the tax amount.

平成25年から令和29年までの各年分の確定申告においては、所得税と復興特別所得税（原則として、その年分の基準所得税額の2.1パーセント）を併せて申告・納付することになります。［2］

Reference translation (unofficial): In the final tax return (kakutei shinkoku) for each year from Heisei 25 (2013) to Reiwa 29 (2047), income tax and special reconstruction income tax (in principle, 2.1% of the base income tax amount for that year) are filed and paid together.

Note that the period of application of the special reconstruction income tax is “from Heisei 25 (2013) to Reiwa 19 (2037),” according to another NTA page (the final tax return preparation corner) and Article 9 of the Reconstruction Funding Act (the Act on Special Measures for Securing Financial Resources Necessary for Reconstruction)［4］. In this article we follow the treatment for that period. Add to the 15% income tax the special reconstruction income tax of 2.1% (based on the income tax amount, which is taxable income × 0.315%) and the resident tax of 5%, and you get 20.315%. This is what “FX is about 20%” actually refers to. Up to this point, the rumor holds.

A future change to the breakdown of the special reconstruction income tax is also planned. According to the NTA, “from 2027 (Reiwa 9) onward, the special reconstruction income tax amount will be 1.1% of the base income tax amount, and the defense special income tax will be filed and paid together with income tax and special reconstruction income tax at a rate of 1% of the base income tax amount”［3］. Since 1.1% + 1% = 2.1%, the total rate applied to the base income tax amount remains 2.1%. The tax rate calculations in this article do not change on that premise.

The problem is when the counterparty falls outside these conditions.

Overseas FX is outside separate self-assessment taxation

The NTA’s final tax return preparation corner page “Tax treatment of foreign exchange margin trading (FX)” has the following note.

平成28年10月1日以後に行う店頭デリバティブ取引のうち、金融商品取引業者（第一種金融商品取引業を行う者に限ります。）又は登録金融機関以外との取引は、申告分離課税ではなく、（注1）の取扱いとなります［4］

Reference translation (unofficial): Among over-the-counter derivatives transactions made on or after October 1, 2016 (Heisei 28), transactions with anyone other than a financial instruments business operator (limited to a person conducting Type I financial instruments business) or a registered financial institution are not subject to separate self-assessment taxation but are treated as described in (Note 1).

What is “the treatment in (Note 1)”? No.1521 explains the case where a non-qualifying trade produces a gain as follows.

一般的には、雑所得として総合課税の対象となりますので、課税総所得金額に応じた税率（超過累進税率）で課税されます。［2］

Reference translation (unofficial): Generally, it is subject to comprehensive taxation as miscellaneous income, and is therefore taxed at a rate that depends on the total taxable income (excess progressive rates).

Put simply: trading with an overseas FX operator that is not registered for financial instruments business in Japan falls outside the special rule for “miscellaneous income, etc. from futures trading.” The profit becomes miscellaneous income (comprehensive taxation). It is added to other income such as salary, and calculated under a system in which the larger the amount, the higher the rate. Even among over-the-counter trades, those that do not qualify as “over-the-counter derivatives transactions” under the Financial Instruments and Exchange Act are treated the same way［4］.

This is where the rumor goes wrong. Only the phrase “FX is taxed separately” has taken on a life of its own, and the condition of “who you are trading with” has dropped out.

The tax rate rises to about 55% at most

The income tax rates for comprehensive taxation are set in the rate table of Income Tax Act, Article 89. The top rate applies only to the portion of taxable total income over ¥40 million.

四千万円を超える金額百分の四十五［1］

Reference translation (unofficial): The portion exceeding ¥40 million: 45/100.

(Excerpt)

Listing the rate table from the lowest income upward, the income tax part has the following seven brackets［1］.

For the income-based portion of resident tax, in the example of Suginami City it is 6% special ward tax plus 4% Tokyo metropolitan tax, for a total of 10%［5］. The special reconstruction income tax of 2.1% is also charged on the base income tax amount［2］. Adding 45% income tax, 10% resident tax and 0.945% special reconstruction income tax (45% × 2.1%) gives a tax rate on overseas FX profit of about 55.945% at most. In the summary we write it as about 55%.

Let’s compare with a concrete example. This is a rough calculation that ignores income deductions, for a case where the FX profit for the year is ¥30 million.

Even with the same ¥30 million profit, the difference in tax is about ¥6.3 million. B’s tax breaks down into about ¥9.2 million of income tax, about ¥190,000 of special reconstruction income tax and ¥3 million of resident tax. The amount left in hand is about ¥23.9 million for A and about ¥17.6 million for B. Note that B’s “about 41%” is the average rate on the whole ¥30 million, which is a different figure from the top rate of 55% (applied only to the portion over ¥40 million).

Only when you have no other income at all and your profit is small (a rough calculation ignoring income deductions), comprehensive taxation can sometimes result in less tax. With a profit of ¥1 million and no other income, comprehensive taxation gives about ¥150,000 in total, such as ¥50,000 of income tax and ¥100,000 of resident tax, which is cheaper than about ¥200,000 under separate taxation. However, for people who already have income, such as company employees, FX profit is stacked on top of salary and reaches a higher-rate bracket.

Pitfall 1: Your options are limited in a year you lose money

Domestic FX has a system that is a strong ally in a year with a loss. A loss that still cannot be fully absorbed after offsetting against other “miscellaneous income, etc. from futures trading” can be carried forward for three years［2］［3］.

NTA Tax Answer No.1523 explains that carry-forward deduction as follows［6］.

「先物取引に係る雑所得等」の金額の計算上生じた損失がある場合に、その損失の金額を翌年以後3年間にわたり繰り越し、その繰り越された年分の「先物取引に係る雑所得等」の金額を限度として、一定の方法により、「先物取引に係る雑所得等」の金額の計算上その損失の金額を差し引くことです。

Reference translation (unofficial): Where a loss arises in calculating the amount of “miscellaneous income, etc. from futures trading,” it is carried forward for the three years following that year, and deducted by a prescribed method in calculating the amount of “miscellaneous income, etc. from futures trading,” up to the amount of “miscellaneous income, etc. from futures trading” for the year to which it is carried.

This system cannot be used for losses on overseas FX. No.1521 explains the case where a non-qualifying trade produces a loss as follows.

上記イのとおり、一般的には雑所得とされることから、雑所得の範囲内での損益の通算は可能ですが、他の各種所得の金額との損益通算はできません。なお、申告分離課税の対象となる「先物取引に係る雑所得等」の金額との損益の通算もできません。［2］

Reference translation (unofficial): As stated in (a) above, because it is generally treated as miscellaneous income, gains and losses can be offset within the scope of miscellaneous income, but cannot be offset against the amounts of other types of income. Offsetting against the amount of “miscellaneous income, etc. from futures trading,” which is subject to separate self-assessment taxation, is also not possible.

In other words, a loss on overseas FX can be offset only within the scope of the same “miscellaneous income.” You cannot deduct it from other income such as salary, offset it against domestic FX profit, or carry it forward to the following year or later. Offsetting against other income and the carry-forward deduction of losses are not available.

Pitfall 2: It is added to your salary and the tax gets even higher

Under comprehensive taxation, your overseas FX profit is added to other income such as salary. Once added, that amount piles up into higher-rate brackets.

Here is an example. A company employee with ¥4 million of salary income earns ¥5 million of profit from overseas FX (a rough calculation that ignores income deductions). Taxable total income becomes ¥9 million. The tax on this ¥5 million increase, adding income tax, special reconstruction income tax and resident tax, is about ¥1.58 million. If the same ¥5 million profit came from domestic FX, the tax would be about ¥1.02 million (20.315%).

The difference is about ¥570,000. The larger the profit, the wider this difference grows. In the ¥30 million example, the difference was about ¥6.3 million.

What to do

First, check which type your counterparty is.

• If you lose money on overseas FX: offsetting against other income and the carry-forward deduction of losses are not available. Offsetting is possible only within miscellaneous income［2］［6］.
• If you lose money on domestic FX: a loss that still cannot be fully absorbed after offsetting against other “miscellaneous income, etc. from futures trading” can be carried forward for three years under certain requirements［2］［3］.
• If you already trade on overseas FX: report the profit as miscellaneous income (comprehensive taxation), added to your other income. Keep your annual trading records, because they are the basis for offsetting within miscellaneous income.
• If in doubt: you can ask the tax office’s consultation counter whether your own trading is subject to separate self-assessment taxation.

Summary

“Overseas FX is a better deal because it is taxed separately” is false. Separate taxation (20.315%) can be used only for trading on an exchange (market derivatives transactions) or for over-the-counter trading with a registered business operator as the counterparty. Trading with an overseas FX operator without registration is miscellaneous income (comprehensive taxation), with income tax up to 45% and up to about 55% including resident tax. The carry-forward deduction of losses is not available either［6］.

“FX is taxed separately” is a statement that assumes the counterparty is an exchange or a registered operator. If your counterparty is an overseas FX operator without registration, it instantly becomes wrong. Rather than just memorizing the tax rate figure, get into the habit of also checking “who you are trading with” and “which tax category applies.”

Sources

• ［1］Income Tax Act, Article 89 (e-Gov Law Search, Japanese)　Checked: 2026-10-05
• ［2］NTA Tax Answer No.1521 “Tax treatment of foreign exchange margin trading (FX)” (Japanese)　Checked: 2026-10-05
• ［3］NTA Tax Answer No.1522 “Special rules for taxation of miscellaneous income, etc. from futures trading” (Japanese)　Checked: 2026-10-05
• ［4］NTA Final Tax Return Preparation Corner “Tax treatment of foreign exchange margin trading (FX)” (Japanese)　Checked: 2026-10-05
• ［5］Suginami City, “Assessment of special ward tax” (Japanese)　Checked: 2026-10-05
• ［6］NTA Tax Answer No.1523 “Carry-forward deduction of losses from settlement of differences in futures trading” (Japanese)　Checked: 2026-10-06

Note: This article is based on laws and official information as of October 7, 2026. It is a translation of the Japanese original; if the two differ, the Japanese version prevails. Quotations from laws and official sources are given in the original Japanese, followed by unofficial reference translations. Sources are limited to laws (e-Gov) and official pages of the NTA and local governments, all in Japanese. If a correction is needed after publication, a correction record will be added at the end of this article (Correction policy).