Available funds(AEE) are used to determine whether new positions may be opened. Opening a position refers to trading activity such as buying long or selling short. Please note that available funds are not the same as available cash. It is calculated using indicators such as total assets, options holdings market value, locked funds, and initial margin. When the available funds are greater than 0, it means the account may open new positions worth up to 4x the available funds.
AEE = ELV - Initial Margin(IM) - locked EE
ELV = Equity with Loan Value = security segment cash balance + total market value of securities - total market value of options