A market order is an order type that executes immediately at the best price possible. Market orders on Delta will always be filled assuming sufficient order book depth, potentially filling at a number of different prices depending on the number of existing orders in the book at the time.
Market orders match against the best available bids/asks in the order book to ensure the best price possible for a trader.A market order can be used when speed is prioritized over the exact order execution price. When placing a market order, a trader prioritizes immediate order execution over price/quantity control.
Example: Using a market order, you can specify the quantity you wish to allocate to an order (e.g. 10% of your wallet). You cannot specify the price however, as this is based on the best available prices in the order book. The order will execute immediately.
For information on further order types, visit Delta Order Types. For video demonstrations, visit the Delta Youtube channel.