A limit order is an order to buy or sell at a specified price or better. A buy limit is an order to purchase the security at the limit price you specify or lower. A sell limit is an order to sell the security at the limit price you specify or higher. The limit order ensures that if the order fills, it will be at the price you specify or better. Please note that a limit order does not guarantee your execution as there can be orders ahead of your order and there may not be enough shares available to fill at that price.