This article is part of Zagdim’s wiki series on tax matters for people moving to Japan. It looks at whether you should organize your stocks, funds, crypto assets, and overseas property before the move, and what cost records and tax documents to keep for each. It is written for readers considering a move to Japan who already hold investments, wherever they are moving from.
**Example (illustrative, used throughout this article):** Mr. Lin currently lives outside Japan and is planning to move there. He holds stocks and funds bought in several batches over time, a rental apartment in Japan, and crypto assets bought on an offshore trading platform.
Should You Organize Your Investment Portfolio Before Moving to Japan?
Yes, at minimum you should organize the cost and transaction records for each asset first. The reason is that Japan calculates taxable gain on a sale, in principle, as “sale proceeds minus cost and expenses”:
- Listed stocks and similar assets: total sale proceeds, minus acquisition cost, minus necessary expenses such as brokerage commission.
- Japanese land and buildings: sale price, minus acquisition cost, minus expenses of sale.
“Acquisition cost” is what you originally paid to acquire the asset. “Necessary expenses” are costs you must pay when selling, such as brokerage commission.
Keeping cost records means that when you eventually file, you can use your actual acquisition cost. Without that, you fall back on the “5% deemed acquisition cost” rule, where 5% of the sale price is used as a substitute for cost when the real cost cannot be traced.
Before organizing anything, you also need to confirm whether you will become a Japanese income tax resident. An individual counts as a resident if they have a residence in Japan, or have had a domicile there for one year or more continuously up to now.
Among residents, there is a further category called a “non-permanent resident,” which is taxed on a different scope of income. This determines whether your overseas gains need to be reported in Japan at all. For more detail, see Zagdim’s articles *Tax Implications for Investors Moving to Japan: Capital Gains, Property Sales, and Overseas Investments* and *Japan Tax Residency and Reporting Overseas Stock Gains*.
What Cost Records Should You Keep for Stocks and Funds?
Keep a record of the price paid, fees, and related consumption tax for every purchase. Under Japanese tax rules, the acquisition cost of stocks and similar assets includes:
- The purchase price
- Purchase commission and related consumption tax
- Fees paid at acquisition to register the asset in your name, such as a name-change fee
Funds should be recorded the same way. A publicly offered investment trust beneficiary interest is a unit in a fund raised from the public. Except for certain specified stock investment trusts, these are treated the same as listed stocks.
If you bought the same stock in two or more batches and later sell only part of your holding, you calculate acquisition cost using the quasi-total-average method: you first work out the average cost per unit, then calculate the cost of the portion sold. This means every purchase record is needed, no matter how far back it goes.
If the acquisition cost cannot be traced, for example because the asset was inherited or bought too long ago, the tax authority allows you to use 5% of the sale proceeds of that same holding as the acquisition cost instead. For how this is classified for filing purposes, see Zagdim’s article *Japan Capital Gains Tax on Stocks and Funds: Rates and Filing*.
**Applied to Mr. Lin’s case:** Mr. Lin bought his stock in several batches. When he later sells only part of it, he will need to use the quasi-total-average method to calculate cost, so every purchase slip needs to be kept.
What Records Should You Keep for Property in Japan and Overseas?
For property in Japan, keep three categories of records separately: cost, expenses of sale, and the holding period. For overseas property, also keep a record of currency conversions.
Taxable gain on selling Japanese land or a building is the sale price, minus acquisition cost, minus expenses of sale. What counts, and what doesn’t:
| Item | Counts | Does Not Count |
|---|---|---|
| Acquisition cost | Purchase price, construction cost, purchase commission, equipment costs, improvement costs | Amounts already claimed as necessary expenses against business income or similar |
| Expenses of sale | Brokerage commission paid to sell the property | Repair costs, fixed asset tax, and other holding or maintenance costs; costs of collecting the sale proceeds (these are not direct expenses of sale) |
The acquisition cost of a building (the structure itself) is further reduced by an amount equivalent to depreciation for the holding period. In plain terms, the portion worn down by years of use is deducted.
If acquisition cost cannot be determined, or the actual acquisition cost is less than 5% of the sale price, you may use 5% of the sale price as the deemed acquisition cost.
How long you held the property also affects classification. This is measured as of January 1 of the year of sale:
- Held more than 5 years: long-term capital gain
- Held 5 years or less: short-term capital gain
See also Zagdim’s article *What Tax Do Foreigners Pay When Selling Property in Japan? Capital Gains and the Effect of Holding Period*.
For overseas property priced in a foreign currency, both the sale proceeds and the original acquisition cost must be converted into yen. In principle, this uses the TTM for each transaction date, the midpoint between the bank’s telegraphic-transfer buying and selling rates.
If the sale proceeds are converted into yen immediately, or yen was converted into foreign currency immediately to buy the property, an alternative rate (TTB/TTS) applies instead. So you need to keep the transaction date, the original-currency amount, and the currency-conversion record together.
**Applied to Mr. Lin’s case:** when Mr. Lin eventually sells his rental apartment in Japan, the commission he pays an agent can count as an expense of sale. The repair costs and fixed asset tax he pays regularly do not count. Whether the gain is long-term or short-term depends on whether he had held the property more than 5 years as of January 1 of the year he sells.
Does Swapping Crypto Assets Also Count as Taxable Income?
Yes. When you swap crypto asset A for crypto asset B, Japan treats this as using A to buy B. So the swap itself requires you to calculate the sale income on A.
Other rules to know:
- When crypto is sold for yen, the income amount is calculated based on the sale proceeds.
- Fees paid when selling can be treated as a necessary expense against the sale income.
- If an individual has not filed a valuation method notification (the document that reports your chosen cost-calculation method to the tax authority), the default method for calculating cost of goods sold is the total average method.
The National Tax Agency allows 5% of the sale proceeds to be used as the acquisition cost. This is an optional alternative, not a requirement; if the actual acquisition cost can be found, compare the two figures before deciding. For how this income is categorized and reported, see Zagdim’s article *How Japan Taxes Cryptocurrency Gains as Miscellaneous Income*.
If you use an offshore exchange, or trade directly with another individual, do not assume you will receive a Japanese-style annual trading report. You need to confirm the acquisition and sale price transaction by transaction yourself, cross-checking against bank deposit and withdrawal records, trading history, and market price data.
If you use a Japan-based exchange and did not receive an annual trading report, you can ask the exchange to reissue one.
**Applied to Mr. Lin’s case:** when Mr. Lin swapped coin A for coin B on an offshore platform, that swap itself requires calculating the sale income on coin A. Mr. Lin should export his trading history now, and also keep his bank deposit and withdrawal records.
What Filing Documents Do You Need to Prepare After Moving?
If you hold substantial overseas assets, or have already paid income tax overseas, you may need to prepare two kinds of documents after moving: a Statement of Overseas Assets, and attachments for the foreign tax credit.
Statement of Overseas Assets is a document that reports your overseas assets to the tax authority.
- Who must file: Residents other than non-permanent residents.
- When it applies: Where the total value of overseas assets held as of December 31 of that year exceeds JPY 50 million.
- Filing deadline: By June 30 of the following year.
- What to report: The type, quantity, and value of the assets.
- Also required: A summary table attached to the Statement of Overseas Assets.
- Exception: Overseas inheritance received in the year inheritance begins is subject to a separate specific exclusion.
Foreign tax credit lets a Japanese resident who has paid foreign income tax deduct that amount from Japanese income tax owed. The deductible amount is capped, calculated based on the proportion that adjusted overseas income represents of total annual income.
To apply, you attach the following to your final tax return (the return filed each year for income tax):
- A statement detailing the foreign tax credit (for residents)
- A copy of the foreign income tax return, or a substitute document
- If the tax has already been paid, proof of payment as well, for example a tax payment certificate or a withholding tax statement
These are not the only required attachments. Check the full list published by the National Tax Agency (see About This Data below).
Which Situations Need Extra Care?
Three kinds of people most need to organize their records early: those who bought assets in multiple batches, those who use offshore platforms, and those who plan to leave Japan later.
- If you bought stocks or crypto in multiple batches: stocks use the quasi-total-average method to calculate acquisition cost when you sell part of a holding. Crypto defaults to the total average method if you have not filed a valuation method notification. Every purchase record is needed either way.
- If you use offshore platforms: export your transaction details and deposit/withdrawal records first. You will need these later to confirm acquisition and sale prices transaction by transaction.
- If you plan to leave Japan later: when a qualifying Japanese resident departs Japan while holding one hundred million yen or more in covered assets, those assets may be treated as if already sold. Japan then taxes the unrealized gain, the increase in value that has accrued but has not yet been locked in through a sale. This is called the exit tax on departure from Japan.
Whether this applies depends on checking the scope of covered assets and your past residence period against the specific conditions. Not everyone holding one hundred million yen or more in assets is subject to it. See also Zagdim’s article *Tax Implications for Investors Moving to Japan: Capital Gains, Property Sales, and Overseas Investments*.
What Should a Pre-Move Checklist Include?
Organize a list by asset category, covering the purchase date, quantity, original-currency amount, fees, and exchange rate. What to keep, by asset type:
| Asset Category | Records to Keep | Used For |
|---|---|---|
| Stocks, funds | Price, quantity, purchase commission and consumption tax, and name-change fee for each purchase; brokerage commission at sale | Calculating acquisition cost and necessary expenses; calculating cost using the quasi-total-average method for batch purchases |
| Japanese land and buildings | Purchase price, construction cost, purchase commission, equipment costs, improvement costs; acquisition date; brokerage commission at sale | Calculating acquisition cost, the depreciation-equivalent deduction, and expenses of sale; determining long-term or short-term classification |
| Overseas property | Transaction date, original-currency amount, and currency-conversion record for each transaction | Converting to yen using the TTM or other applicable rate |
| Crypto assets | Acquisition and sale price for each transaction, sale fees, trading history, bank deposit and withdrawal records; annual trading report from a domestic exchange | Confirming acquisition cost; calculating cost of goods sold and sale income |
| Foreign income tax already paid | Copy of the foreign tax return or substitute document, proof of payment | Applying for the foreign tax credit |
Residency status, asset size, and the scope of reporting differ for everyone.
Frequently Asked Questions
Does everyone moving to Japan with overseas assets have to file a Statement of Overseas Assets?
No. Two conditions must both be met: you are a resident other than a non-permanent resident, and the total value of your overseas assets as of December 31 of that year exceeds JPY 50 million. If both apply, the filing deadline is June 30 of the following year. Overseas inheritance received in the year inheritance begins is subject to a separate specific exclusion.
What if you can’t trace the cost of a stock or crypto asset?
For stocks, if the acquisition cost cannot be traced, for example because the asset was inherited or bought too long ago, you may use 5% of the sale proceeds of that same holding as the acquisition cost. For crypto, you may use 5% of the sale proceeds as the acquisition cost. Either way, if the actual acquisition cost can be found, compare the two figures before deciding.
Are the trading records from an offshore crypto platform enough on their own?
Do not assume an offshore exchange will give you a Japanese-style annual trading report. You need to confirm the acquisition and sale price transaction by transaction yourself, using bank deposit and withdrawal records, trading history, and market price data. If you use a domestic exchange and did not receive an annual trading report, you can ask the exchange to reissue one.
Glossary
- Acquisition cost (shutoku-hi): what you originally paid to acquire an asset, used in calculating taxable gain on sale.
- Quasi-total-average method (jun-sōheikin-hō): the method used to calculate the cost of stock sold when the same stock was bought in two or more batches.
- Total average method (sōheikin-hō): the default method for calculating cost of goods sold for crypto assets, used when no valuation method notification has been filed.
- TTM: the midpoint between a bank’s telegraphic-transfer buying and selling rates, used to convert foreign-currency transactions into yen.
- Statement of Overseas Assets (kokugai zaisan chōsho): a document reporting the type, quantity, and value of assets held overseas to the tax authority.
- Exit tax on departure from Japan: a rule that can tax unrealized gains on covered assets when a qualifying resident leaves Japan.
About This Data
Facts were checked as of October 21, 2026. The pre-move checklist and the advice on what records to keep are drawn from the National Tax Agency’s No. 1463, No. 1464, No. 3202, No. 3252, No. 3255, and No. 3560, and from its crypto asset FAQ; the National Tax Agency has not itself published a single consolidated pre-move checklist.
The required attachments for the foreign tax credit are not limited to the items listed in this article; the full list is published in the National Tax Agency’s No. 1240. The following are not covered in this article and should be checked against the full official text: whether a loss on selling listed stock can offset ordinary stock sale gains, the full calculation of crypto sale income, whether purchase fees are included in crypto acquisition cost, and the complete list of foreign tax credit attachments. The scope of covered assets and the residence-period conditions for the exit tax on departure from Japan are not worked through item by item here; individual cases should be checked against the National Tax Agency’s No. 1478. This article does not include any system changes that have not yet been announced or are still under review.
Mr. Lin’s scenario in this article is a fictional example used only to illustrate how the rules apply.
Have a question about this guide? Leave a comment below, or ask Zagdim directly.
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Sources
- National Tax Agency — No. 2010, Who Is Liable to Pay Tax
- National Tax Agency — No. 1463, Taxation on the Transfer of Stocks (Separate Self-Assessment Taxation)
- National Tax Agency — No. 1464, Acquisition Cost of Transferred Stocks
- National Tax Agency — No. 3202, How to Calculate Capital Gains (Separate Taxation)
- National Tax Agency — No. 3252, What Counts as Acquisition Cost
- National Tax Agency — No. 3255, What Counts as Expenses of Sale
- National Tax Agency — No. 3560, Tax Treatment When a Resident Sells Overseas Real Estate
- National Tax Agency — No. 1240, Foreign Tax Credit for Residents
- National Tax Agency — No. 7456, Obligation to File a Statement of Overseas Assets
- National Tax Agency — Tax Treatment of Cryptocurrency (Information)
- National Tax Agency — No. 1478, Special Rules for Capital Gains and Similar Income on Departure From Japan
Important Notice
This article is a general information summary and does not constitute tax or legal advice for any individual case. Facts were checked as of October 21, 2026. Japanese regulations may be updated; refer to the relevant authority’s current published information, and consult a qualified professional for individual cases.
