Free credit balances above $250,000 will be swept to one or more banks in the Insured Bank Deposit Sweep Program. Free credit is generally defined as USD cash in your IBKR account in excess of margin requirements and short stock value, within the minimum and maximum balance criteria for the Program.
The balance is calculated as of the close of business each day and swept into the Program on the next business day. The first $250,000 remaining at IBKR is protected by SIPC.