Investments, stock capital gains, currency conversion method, and exiting the business

Income from selling stocks (capital gains) is taxed at a flat 20.315% (15.315% national + 5% local), unlike the progressive scale for ordinary income and cryptocurrency; buying stocks and securities in Japan is not itself taxed. NISA exempts gains from tax on sale if an asset is held for 5 years after purchase; no equivalent relief exists for real estate in Japan, unlike, for example, Russia or Kazakhstan, where 3 years of ownership exempts capital gains from tax (not 100% confirmed). A NISA investment limit up to 4 million yen was mentioned. iDeCo is a separate pension investment account with tax benefits; for a non-resident who has left Japan, an equivalent investment account can effectively "fall away" — relevant to tax residency planning. For calculating capital gains, it is legal to choose the TTB/TTS method (buy/sell rate) instead of TTM (the average rate) and apply that choice consistently "for the rest of one's days"; combining TTB and TTS is almost always more favorable than TTM but takes more effort. Deliberately exploiting the scheme — generating trades with near-zero currency profit purely to inflate turnover for appearances or visa purposes — is not allowed; the line between legitimate optimization and abuse is judged at the inspector's discretion. On exiting a business: selling a local "unicorn" (business) in Japan is taxed at 20%+ at the time of sale; and on leaving the country, if lifetime income exceeds 600,000 USD, an additional 15% exit tax is levied on all assets, both sold and unsold. Source: https://www.nta.go.jp/law/tsutatsu/kobetsu/shotoku/sochiho/020624/sanrin/1273/37_10-11/01.htm — Official NTA explanation of currency conversion methods for capital gains purposes..