Regarding the calculation of P&L for transactions in foreign currencies, the rate between the foreign currency and JPY is required when calculating the P&L in JPY. In accordance with the Basic Notice 57-3-2 of the Income Tax Law, the default rate is TTM.
However, as an exception to this rule, there may be cases where the application of the bid/TTS (when buying) and ask/TTB (when selling) rates for foreign currency telegraphic transactions is allowed for some income categories.
How to change the adoption rate
If you want to change to the TTS/TTB rate at your own discretion, please make the following settings.
Please note that you are supposed to continue to use one of the rates once you changed. If you wish to change the rate, please contact your local tax office.
1. Click on the Settings button to the left of "Add transactions"
2. Open the advanced settings and turn off "Always use TTM for FX prices" (when it is off, it will be grayed out as shown in the figure) and click Update.