A market order is the simplest of orders and is used when the greatest priority of the customer is for immediate execution. A market order instructs your broker to buy or sell futures contracts immediately at the market price, the best possible price for immediate execution. Market orders are the easiest way to enter or exit a market since the customer receives immediate execution - and must pay or receive whatever price is necessary for immediate execution.
When you place a market order, you are asking that order to be filled at the best available price immediately after receipt of the order. You might say, "Buy 2 December Swiss francs at the market." After the brokerage firm writes up this order, it’s rushed to the floor broker in the pit who executes it right away. Or, if you place an order online for one of the electronically traded contracts, your order is filled via a computer matching system.
Example: My account # is 12345 and I want to Buy 1 May Corn at the market. (This would enable you to go ‘Long’ at the market, or exit a short position. You could also use this order to Sell 1 May Corn at the market also and go ‘Short’ or exit a long position.)
Market on Open (MOO) As the name implies, this order will be executed on the market open within the opening range. This trade is used to enter a new trade, or exit an open trade.
Example: My account # is 12345 and I want to Buy (or sell) 1 May Corn at the Market on Open.
Market on Close (MOC) As the name implies, this order will be executed on the market close. The fill price will be within the closing range, which may, in some markets, be substantially different from the settlement price. This trade is used to enter a new trade, or exit an open trade.
Example: My account # is 12345 and I want to Buy (or sell) 1 May Corn at the Market on Close.