A market order is an order to buy or sell a stock at the best available price. Generally, this type of order will be executed immediately. However, the price at which a market order will be executed is not guaranteed.

A market order on Stake can be placed at any time, but will only be executed when the market is open.   

To place the buy market order on web or app, once you have elected a market order for your buy, enter the dollar amount you want to transact.  For sells, you can enter the number of shares you want to sell. 

Market orders placed during the market will be executed immediately, while those placed outside of market hours will be queued and remain pending until the market next opens or you delete them.