Market Order
A market order is an order to buy or sell a security at the current market price. If the order is placed during market hours, or 9:30 am to 4:00 pm EST, the order will be executed immediately. This order is used when an order needs to be executed immediately, regardless of price. Of course, the downside is that you may get a worse price as opposed to a limit order.

If you place a market order outside of market hours, the order will be executed at the time the market next opens. For example, placing a market order at 8:30 AM on Wednesday will result in an execution at 9:30 AM on Wednesday, the same day the order was placed. Placing a market order at 5:00 PM on Monday will result in an execution at the next day's open, or 9:30 AM on Tuesday.

Limit Order
A limit order is an order to buy or sell a security at a given price. Once the security reaches or surpasses the price chosen by you, the order is activated. This order is used when an order needs to be executed only at a certain price or better.

For example, if you place a limit order to buy 100 shares of Microsoft at $24.50, the order will not be executed unless the stock trades at $24.50 or better. This is helpful when you do not want to pay more than a certain price for a stock. Of course, the downside is that your order may not execute at all.

Keep in mind that although a security may reach your limit order price, there is no guarantee that your order will be filled. In some cases, only a portion of your order may be filled, as the security may not remain at your chosen price level for a time sufficiently long enough to fill your order completely.

Limit Order Expiration
All SogoTrade Limit orders have Day Expiration. This means the order will be in effect on the day that it is entered, and will expire at the end of the trading day, at 4:00 PM Eastern Time.