I found out by trial -and-error, thesolution to the 'technical issue' ! (Which the technical help did not know ! ) You have to convert any balances into your base currency and then you can move amounts of your base currency to wherever you want. If you want to use your funds in their new home in a different currency you must then convert them again. That means if your base Currency is say UK£ and you have a balance of US$ in one account and you want to use it to buy a US$ denominated holding in another account, you have to Convert the Dollars in Account One into your base UK£. Then you can move UK£ from Account One to Account Two. Then in Account Two you must convert your UK£ back into US$ and then you have dollars to what it was you wanted to do in US$. In fairness, I thought I would lose a bit of a fee or spread on each conversion, but, unless I was just lucky with the way the currencies moved, while I was mucking about, IG did seem to do each conversion at the same UK: $ Rate. What it does mean is that if you change your mind about whatever you wanted to use your US$ to do, you must decided in which currency you wish to hold your balance while you wait