I know this a stupid question. I am a total newbee. I have 100K GBP, and I bought 1M NZD. Assume GBP/NZD exchange rate is about 2. So I have a position of GBP -400K and NZD +1M. I pay interest as I borrowed 400K GBP from IB. The question is do I earn interest rate from the 1M NZD in my account.