Market order

What a market order means

A market order is an instruction to buy or sell an instrument straight away at whatever price is currently available. You do not name a price. You name the instrument and the size, and the broker or exchange fills the order against the best quotes it can find. Speed and certainty of execution come first; certainty of price does not.

It is the simplest order type and the default on most platforms, which is why beginners use it most. A buy market order is filled at or near the current ask price, and a sell market order at or near the current bid. The difference between those prices is the spread, and a market order pays it in full.

Market orders are used on every kind of instrument: shares, ETFs, forex, CFDs, futures and options. They appear when entering a position, closing one, or when a stop-loss order triggers and turns into a market order to get out.

How it works

When you press buy or sell, the order goes to the broker's system, which routes it to a venue or fills it from its own pricing, depending on the execution model.

1. The platform shows a quote, for example 100.20 bid and 100.24 ask.
2. You send a market order to buy. The system looks for sellers at the ask.
3. If enough size is offered at 100.24, you fill there. If not, the rest fills at the next price levels up the order book.
4. The fill price is reported back, together with any fees or commission.

Two things can make the fill differ from the quote you saw. The first is latency: prices move in the fraction of a second between your click and the fill. The second is depth: a large order can consume several price levels, so the average fill price is worse than the top quote. Both effects together are called slippage.

Some brokers offer a price tolerance or maximum deviation setting on market orders. If the price has moved beyond your tolerance, the order is rejected or requoted instead of filled.

A worked example

These numbers are illustrative. A share trades with this simplified order book of offers to sell:

• 200 shares at 50.00
• 300 shares at 50.02
• 500 shares at 50.05

You send a market order to buy 600 shares.

• 200 shares fill at 50.00, costing 10,000.00.
• 300 shares fill at 50.02, costing 15,006.00.
• 100 shares fill at 50.05, costing 5,005.00.

Total cost is 30,011.00 for 600 shares, so the average price is 30,011 ÷ 600 = 50.018. The quote you saw was 50.00, so the average fill is about 0.018 per share worse, or roughly 10.80 in total. In a calm, deep market the difference might be zero; in a thin one it can be much larger.

Why it matters

A market order trades certainty of execution against uncertainty of price. In liquid instruments in normal hours the cost of that trade-off is usually small and often limited to the spread. In thin markets, around news releases, at the open, or in the dark hours of an illiquid share, it can be large.

The order type also matters for risk control. A stop-loss is commonly executed as a market order once triggered, so in a gap or fast move the fill can be far from the stop price. That is not an error; it is how the order works.

Brokers differ in how they handle market orders. Some fill at the quote shown, some apply a tolerance, and some fill at the next available price. These choices affect your real trading cost more than a tiny difference in headline spread.

How to use it in practice

1. Use a market order when getting in or out matters more than a few ticks of price, and the market is liquid.
2. Check the spread and displayed depth before sending a large order.
3. Avoid market orders in the minutes around scheduled news or at the opening and closing auctions of thinly traded shares.
4. Consider a limit order when price control matters more than immediate execution.
5. Review the fill report and compare it with the quote at the time of the click.
6. Learn your platform's deviation or slippage setting and set it deliberately.

Common mistakes and misconceptions

• Thinking the price on screen is the price you will get. It is an indication; the fill can differ.
• Sending large market orders in illiquid shares or options. Correct it by splitting the order or using a limit.
• Using market orders outside regular trading hours, where spreads are wide and quotes are thin.
• Assuming a stop-loss guarantees the exit price. A triggered stop usually becomes a market order and can slip.
• Ignoring the spread, which is a cost you pay immediately on entry.
• Believing that market orders are always instant. Network delay, rejections and halted trading can interrupt them.

Risks and limitations

A market order gives no protection against sudden price moves. In a gap, a halt or a fast market, the fill can be far from what you expected, and with leveraged products such as CFDs that difference can magnify losses quickly. Execution rules differ between brokers and venues, and a few instruments do not accept market orders at all outside certain hours.

How Brokeli looks at it

When we review a broker we look at which order types are offered, how execution and slippage are described, and what the order execution policy says about market orders. Spread and fee data come from published research snapshots, so comparisons rest on the same documented basis. We do not give trade instructions; we describe how the order type works.