If your trading of crypto assets (also known as virtual currencies) ended the year in the red, you may wonder whether you still need to file a tax return in Japan. It's widely known that profits from crypto trading are taxable, but how losses are treated is often less clear.

Under Japanese tax law, profits from crypto assets are classified as "miscellaneous income." As a result, if your overall gains and losses for the year are negative, a tax return is, in principle, not required. That said, there are situations where a tax return is still required even if your crypto trading ended in a loss.

This article explains the basic rules around filing a tax return when crypto trading results in a loss, and the cases where filing is still required.

Editor's note: This overview reflects Japan's tax rules as of March 2026, under which crypto gains are taxed as miscellaneous income subject to aggregate (comprehensive) taxation. Following Japan's 2026 amendment to the Financial Instruments and Exchange Act (FIEA), crypto assets have been reclassified as financial products; a shift to flat 20% separate self-assessment taxation is targeted for 2028 but has not yet taken effect, so the rules described below remain current.

In principle, a tax return is not required when crypto trading results in a loss

As noted above, when crypto trading generates a profit, that profit is classified under Japanese tax law as "miscellaneous income" — a catch-all category for income that doesn't fall under employment income, business income, or similar categories. Tax is owed when your trading activity for the year results in net income, meaning you ended up with a realized gain, for example through the sale of crypto assets.

On the other hand, if your trading results for the year are negative — that is, you incurred a loss — no income has been generated. In that case, a tax return is, in principle, not required when your crypto gains and losses net out to a loss for the year. However, depending on your other sources of income, a tax return may still be required even if your crypto position is in the red.

Cases where a tax return is still required despite a crypto loss

Because crypto gains and losses are classified as "miscellaneous income" under Japanese tax law, whether you need to file a tax return isn't determined by your crypto results alone — it depends on your overall income picture, including employment income and side-business income.

Below are the main cases in which a tax return is still required even if your crypto trading ended in a loss.

Salaried employees with more than ¥200,000 in non-employment income

Salaried employees in Japan are subject to a rule requiring a final tax return (annual tax filing) if their non-employment income exceeds ¥200,000 (roughly USD 1,300, based on an approximate rate of ¥150/USD) in a given year. Non-employment income here includes side-business earnings, manuscript fees, online income, and — crucially — crypto profits, which are also classified as miscellaneous income under tax law.

If your crypto trading results for the year are negative, that loss itself is not something you report on a tax return. However, if your side-business income (or other non-employment income) exceeds ¥200,000 for the year, a tax return is required regardless of your crypto results.

In this case, the reason a tax return is required is the side-business income — not the crypto loss itself. Still, since filing a tax return means totaling up all of your income, it's important to keep track of your crypto trading activity as well.

When crypto trading is treated as business income

Profits from crypto trading are, in principle, classified under tax law as "miscellaneous income." For individuals trading crypto as part of general asset management, this is typically the applicable category. However, depending on the circumstances of your trading activity, a different income classification may apply. For example, if your annual crypto-related income exceeds ¥3 million (roughly USD 20,000) and you keep bookkeeping records of your trading, your income is, in principle, treated as business income.

Gains or losses arising from crypto asset trading are recognized based on their relative value against the Japanese yen or a foreign currency, and are therefore, in principle, classified as miscellaneous income (other miscellaneous income). However, if a taxpayer's crypto-related income for the year exceeds ¥3 million, the income is classified as follows:

· Where bookkeeping records related to crypto trading are maintained: in principle, business income (see note)· Where such bookkeeping records are not maintained: in principle, miscellaneous income (miscellaneous income arising from business-related activity)

(Note) Even where bookkeeping records related to crypto trading are maintained, if the trading is not found to have a profit-seeking nature, whether it qualifies as business income is determined on a case-by-case basis.

In addition, where crypto trading is "incidental to activity that itself gives rise to business income" — for example, where a business owner holds crypto assets as a business asset and uses them as a means of settlement when purchasing inventory — the resulting income is classified as business income.

Source: Tax Treatment of Crypto Assets, etc. | National Tax Agency (NTA)

Business income refers to income generated from ongoing business activity. If your crypto trading is determined to be conducted as a business, the resulting gains or losses may be treated as business income. In this case, even if your trading results are negative, you still need to calculate your business income as part of your tax filing, meaning a tax return may be required even when you're operating at a loss.

Key tax considerations for crypto losses

The tax treatment of crypto losses in Japan differs significantly from that of stock investing. Crypto losses are subject to specific restrictions under the tax code, which limit how far they can reduce your tax liability. As a result, there are cases where a crypto loss provides no tax relief at all.

Below are the key points to be aware of regarding crypto losses.

Crypto losses cannot be offset against other income

If you incur a loss from crypto trading, as of the current rules (as of March 2026) that loss cannot be offset against other income, such as employment income. Under Japanese tax law, crypto assets are classified as miscellaneous income, and offsetting of gains and losses is not permitted between miscellaneous income and other income categories. Crucially, this means a crypto loss can only be offset within miscellaneous income itself — it cannot be offset against employment income or any other income category.

Offsetting of gains and losses refers to a mechanism that allows a loss in one income category to be deducted against a gain in another. For example, if you incur a loss from real estate income, that loss can, in some cases, be deducted from your employment income to reduce your taxable income.

Crypto losses, however, fall outside this mechanism. For instance, if you have ¥5 million in employment income and incur a ¥1 million loss from crypto trading, your taxable income remains ¥5 million. In other words, even if you have employment income, you cannot deduct a crypto loss from it to reduce your tax bill.

Crypto losses cannot be carried forward to the following year

Losses from crypto trading, as of the current rules (as of March 2026), cannot be carried forward to future years. This is because loss carryforward deductions are not permitted for miscellaneous income.

A loss carryforward deduction is a mechanism that allows a loss incurred in one year to be offset against gains in future years. For example, with stock trading, filing a tax return allows losses to be carried forward for up to three years and offset against future gains. Crypto trading, however, is not eligible for this mechanism. If you incur a ¥1 million loss from crypto trading in one year and then generate a ¥1 million gain the following year, you cannot deduct the prior year's loss — the full ¥1 million gain in the following year remains taxable.

In short, a crypto loss cannot be applied to reduce your tax liability in future years. This is an important distinction from stock investing to keep in mind.

Summary

If you incur a loss from crypto trading, a tax return is, in principle, not required. This is because no taxable income has arisen when your annual gains and losses net out to a loss.

That said, depending on your overall income situation, a tax return may still be required — for example, if you're a salaried employee with more than ¥200,000 in non-employment income, or if your crypto trading is treated as business income. In addition, crypto losses are subject to specific restrictions under the tax code: they cannot be offset against other income, such as employment income, and unlike stock investing, they cannot be carried forward to future years.

As shown here, the tax treatment of crypto assets differs in important ways from that of stock investing. To prepare for future tax filings or a potential tax audit, it's important to keep ongoing records of your trading history and gains or losses.

This article is for informational purposes only and does not constitute financial or investment advice. Please consult a qualified professional before making investment decisions.