Please login into your Trading Platform, click on My Profile and then Sub-account Transfer:
Currency conversion fee
When you trade an instrument in a currency that differs from your base denomination, conversions—including trading profits/losses—are executed using the FX spot mid-price, based on the time you close your position plus/minus 0.45 percent. We charge no more than plus/minus 0.45 percent in currency conversion fees.
If you transfer cash between your sub accounts, the same currency conversion fee applies.
The currency conversion fee does not apply to margin collateral. Only settlement of actual payments to or from the trading account are included—for example, buying/selling cash stocks or paying/receiving options premiums.
The rate used for currency conversion of amounts booked to your account is shown in the trading platforms under the Trades Executed report.