A method of determining whether to approve trading order requests is provided. A request to place a first trading order is received from a user using a trading account associated with the user. A risk value is determined for the first trading order. A plurality of balances associated with the trading account are determined. The balances may include an available cash balance, an available credit balance, and an available waived margin balance for the trading account. A determination of whether to approve the first trading order is made based at least in part on the risk value for the first trading order and the available cash balance, the available credit balance, and the available waived margin balance determined for the trading account. If the first trading order is approved, the first trading order is placed.