Given that the auto-scaling percentages around in “whole” numbers, the reason for the cash left in your account is because the strategy is not trading the complete amount.
For eg. If the model account is at 270K and you started with 50K, the ideal auto-scale is 18.57% (50K/ 270K). Since the auto-scaling is in whole numbers, you would therefore have set it up to 18%.
The remaining 0.57% would still be in your account as cash.
You now have two options.
Option 1: Increase the 18.57% to 19%; which would mean that you are now trading more money than you have in the account and therefore using margin. The margin cost in IB is very low so normally this would not be a problem.
However IRA accounts are not allowed to trade a higher capital than what they are funded with, so this option would not work for IRA accounts
Option 2: Stay at 18% and trade the remaining 0.57% in a low volatility bond fund so that you make some money from it. I would recommend using either MINT or GSY as the ETF to put the balance money in.
Either option would work. I would recommend Option 1 for regular accounts and Option 2 for IRA accounts.
