For some countries TAX Ids are not mandatory i.e. Thailand, as you are only obliged to apply for a tax id when transfering capital gains or interest in the same year when they were generated or when you have a visa that allows you to work here. Some banks fail to understand this at first but usually come around to it. In reality I never heard that anyone ever had to pay taxes on their interest earned outside of Thailand, but this could change so dont transfer in the same year to be on the safe side.