In plain English
What Market order means
A market order tells the broker or exchange to execute now, using whatever prices are available when the order reaches the market. In a liquid market it often fills quickly near the quoted price; in a fast or thin market, the final fill can be noticeably different from the last quote.
Why it matters
Market orders emphasize speed, not price control. That matters because the fill price can move between order entry and execution, especially when liquidity is thin or volatility is high. For forex and CFDs, that can change the realized cost of the trade through slippage.
Example
If EUR/USD is quoted at 1.0840/1.0842 and you send a buy market order for 10,000 units, the order may fill at 1.0842 or slightly worse if the quote changes before execution. This example is simplified and ignores fees and spread changes.
Quick answers
Common questions
Does a market order always fill completely?+
No. It usually aims for immediate execution, but partial fills can happen if available liquidity is limited.
Is a market order risky in forex?+
It can be, because prices can change during execution and forex is traded over the counter, not on one central book.
Sources