IBKR Australia only supports currency balances in AUD, USD, HKD, EUR and GBP, and clients are able convert between these currencies as described here: How can I convert currency? If you hold cash balances in currencies other than IBKR Australia supported currencies (AUD, USD, HKD, GBP or EUR), they will to be converted into your nominated base currency.
IBKR Australia clients, when permissioned, can trade in any market available across the IBKR network, even those outside the 5 supported currencies above. However, upon trading any market outside the 5 supported currencies IBKR Australia will automatically execute Forex conversions to ensure non-supported cash balances are cleared.
For example, if an IBKR Australia client using a Cash account wishes to buy JPY denominated securities, as long as the client has sufficient available funds the trade will be permitted. To settle the trade, IBKR Australia will convert the existing cash balances into JPY. Similarly, at a later date, if the same client wishes to sell their JPY denominated securities IBKR Australia would automatically convert the JPY proceeds to the base currency by day's end, once again leaving no residual JPY cash balances.
If an IBKR Australia client using a margin account has any positive or negative cash balances outside of the 5 supported currencies, it will be automatically converted to base currency by day's end.
Additional Information
- IBKR Australia account types and product offerings in the IBKR Knowledge Base.