Market order
A market order is an instruction to buy or sell immediately at the best price currently available.
It prioritises execution over price: the order fills as fast as the book allows, at whatever price the available liquidity produces at that instant. In a calm market that price matches the screen; in a fast or thin market it can differ.
This page covers the mechanic; it is not trading advice.
Execution now, price not guaranteed
A market order is the simplest of the Order types: it tells the broker to fill at once, at whatever price the market offers. A buy market order on EUR/USD lifts the best available ask; a sell market order hits the best available bid. The trade-off is fixed in the design — the order guarantees that it will fill, but not the price it fills at.
That trade-off is invisible in a deep market and obvious in a thin one. With ample depth at the top of the book, a 1 standard lot buy fills entirely at the displayed ask. When the depth at the best price is smaller than the order, the order fills part at the best price and the rest one or two levels worse, a partial fill walked across the book. The larger the order relative to the depth, the worse the average fill.
The common assumption is that the price shown when the button is pressed is the price paid. It is the price requested. Between the click and the fill the market can move, and on a market order the trader accepts whatever price results — this is Slippage, the price of demanding immediate execution. A trader who needs the displayed price rather than immediate execution is describing a Limit order, not a market order.
When a market order fits, and what it costs
The cost of a market order is the Spread plus any slippage, and any commission on a raw-spread account. At the London-New York overlap the EUR/USD spread floor is 0.1 to 0.3 pips with negligible slippage; on a standard account, or outside the overlap, it is wider. At the moment of a data release the same order can slip several pips: a buy requested at 1.0822 filling at 1.0828 pays six pips of slippage, $60 on a 1 standard lot position, on top of the spread.
A market order suits the moments when being in or out of the position matters more than the precise price: closing a losing trade that has reached its Stop-loss level, or entering when a setup has confirmed and waiting risks missing the move. It is the wrong tool when the entry price is the whole thesis, because it will pay whatever the market asks.
Partial fills and thin markets
On a thin instrument or in a thin session, a market order large enough to exceed the resting depth fills in pieces at progressively worse prices. The platform reports a single average fill, but that average can sit well away from the screen price. The defence is size: an order kept small relative to the visible depth fills cleanly, while one that dwarfs the book moves the price it is trying to take. This is the same Liquidity mechanic that widens the spread on exotic pairs, seen from the order side.
Market execution versus instant execution
How the fill is handled depends on the broker's execution model. Under market execution the order is filled at the going price and any difference is reported as Slippage; the price is never rejected. Under instant execution the platform holds the trader to the displayed price and, if it has moved, returns a requote to accept or decline rather than filling. Market execution is the model in which a market order behaves as described here: it always fills whenever liquidity exists, and the price is whatever the book produces.
Order typesHow the market, limit, stop, and stop-limit instructions compare, and when each is used.Related terms
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Common questions
Does a market order guarantee the price I see?
No. A market order guarantees that it will fill, not the price it fills at. In a calm, deep market the fill matches the displayed price within a fraction of a pip. In a fast market or a thin one the price can have moved by the time the order arrives, and the fill comes back better or, more often, worse than displayed. The gap between the displayed price and the fill is slippage.
When does a market order slip?
When the market is moving fast or the book is thin between submission and execution: the seconds around a scheduled data release, the session edges and the daily rollover, illiquid instruments, and the weekend gap. It also slips when the order is large relative to the depth resting at the best price, because the order has to fill across several levels. Deep-liquidity windows such as the London-New York overlap produce the least slippage.
What is the difference between a market order and a limit order?
A market order guarantees execution but not price; a limit order guarantees price but not execution. A market buy fills now at the best available ask, accepting any slippage. A buy limit fills only at its set price or below and never worse, but if the market never reaches that price the order does not fill. The choice is between certainty of being in the trade and certainty of the entry price.
Is a market order the same as instant execution?
No. A market order is an instruction; instant execution is one way a broker handles it. Under a market-execution model the order fills at the best available price and reports any slippage. Under an instant-execution model the broker may requote if the price has moved rather than fill at the new price. The same market order can therefore fill silently on one account type and trigger a requote prompt on another.