Order types explained: market, limit, stop, stop-limit and OCO
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Choosing an order type means choosing between price certainty and execution certainty. A practical guide to each order, with its traps.
- Market order: guaranteed execution, no guaranteed price.
- Limit order: guaranteed price (or better), no guaranteed execution.
- A stop turns into a market order once triggered; a stop-limit may never fill.
- An OCO links a stop and a target: when one fills, the other is cancelled.
Placing an order looks trivial: you click “buy”. Yet the order type determines the price you pay, the risk of not being filled, the fees and sometimes the size of the loss in a violent move. Every order rests on a single trade-off: price certainty or execution certainty. You can never have both.
The market order
A market order buys or sells immediately at the best price available in the order book. It consumes displayed liquidity: it is an aggressive order that pays the spread and usually the highest fee (“taker”).
- Upside: near-certain, immediate execution.
- Risk: slippage. If your size exceeds what is available at the best price, the order “walks the book” and partly fills at worse prices.
Use it when getting in or out now matters more than a few ticks: cutting a loss, reacting to a breakout.
The limit order
A limit order sets the maximum buy price (or minimum sell price). It fills at that price or better, never worse. If it cannot fill right away it joins the book and waits: a passive order, often charged a lower fee (“maker”).
- Upside: full price control, no slippage.
- Risk: never getting filled. Price can touch your limit without your order being served, because orders at each price are filled in arrival order (the queue).
Tip: a buy limit placed above the current price fills immediately — like a market order but with a price cap. It is a good way to enter fast while avoiding excessive slippage.
The stop order (stop-loss, stop-market)
A stop order sleeps until price reaches a trigger level, then becomes a market order. It is the standard stop-loss tool: “if price drops to 59,100, sell”.
Because it turns into a market order, execution is guaranteed but price is not. In a flash crash or a stock-market opening gap, a stop can fill well below the planned level. Stops can also be used to enter: a buy stop above resistance buys the breakout only if it actually happens.
The stop-limit order
A stop-limit combines both: when triggered, it places a limit order instead of a market order. You set two prices: the trigger and the limit.
It avoids absurd fills but adds a serious danger: if the market blows through your limit too fast, the order sits in the book unfilled… and your losing position stays open. For protective stops, most traders therefore prefer the stop-market.
The OCO order (One Cancels the Other)
An OCO pairs two orders: typically a take-profit (limit) and a stop-loss (stop). As soon as one fills, the other is cancelled automatically. It is the cleanest way to manage a position without watching it: target and protection are set at entry.
Time-in-force options
| Option | Meaning |
|---|---|
| GTC (Good Till Cancelled) | Valid until cancelled |
| Day | Cancelled at the session close (stock markets) |
| IOC (Immediate Or Cancel) | Fills what it can immediately, cancels the rest |
| FOK (Fill Or Kill) | All or nothing, immediately |
| Post-only | Cancelled if it would fill immediately: guarantees maker status |
Which order for which situation?
| Situation | Suggested order |
|---|---|
| Enter at a precise support level | Limit |
| Enter on a confirmed breakout | Buy stop (or a limit above price) |
| Protect a position | Stop-market |
| Take profit at a target | Limit (ideally OCO with the stop) |
| Emergency exit | Market |
Practise
The Bullmarket simulator offers market and limit orders, with a stop-loss and take-profit attached to the position — the equivalent of an OCO. Fees differ depending on whether you are aggressive (market, stop) or passive (limit, target), so you can measure their real impact on your results.
Educational content only — not investment advice. Trading involves the risk of losing capital.