Hello forum. I am trying to get my head around the following. I have 10.000 USD in a margin account at Interactive Brokers. And I buy 5.000 USD worth of GOOG and sell 5.000 USD worth of FB. So I have: 10.000 USD cash 5.000 USD of GOOG -5.000 USD of FB And I hold this position for one year. What can expect to pay and receive in interest? That is: 1. Interest received on 10.000 USD in cash? 2. Interest received for allowing shorting of GOOG? 3. Interest paid for shorting of FB? Any additional fees? As far as I can see the following applies: 1. Currently 0%. https://www.interactivebrokers.com/en/index.php?f=interest&p=schedule 0% 10,000.01 + 0% (BM - 0.5%) Where BM is the overnight fed funds rate. Currently 0.370% 2. None 3. After SLB - Shortable Instruments Tool found under account management: Symbol @ Exchange: FB @ ARCA Quantity Available: >10'000'000 shares Current Rebate Rate*: 0.1200% Current Fee Rate**: 0.2500% I think I will paid last of the two rates: 0.2500% Is this correct? Suppose I increase the positions from 5.000/-5.000+10.000 to 7.500/-7.500+10.000? Does it makes any difference to the interest paid?