A stop order, often called a stop-loss order, becomes a market order once the stock trades at the stop price, so it exits at the next available price, which can be well below the stop. A stop-limit order becomes a limit order instead: it will not sell below the limit price you set, which protects the price but means the order may not fill at all.
How it works
Both orders rest unexecuted until a trigger is reached. The stop price is that trigger, not a promised fill. A sell stop sits below the current price and protects a long position; a buy stop sits above it and protects a short position or enters a breakout.
- Stop order (stop-market). When the stop price is reached, the order becomes a market order and is filled at the best price then available. In an orderly market that is at or close to the stop. In a fast decline or a gap, the fill can be far below it.
- Stop-limit order. It carries two prices: the stop price, which triggers it, and the limit price, the worst price you accept. For a sell order the limit is usually set at or a little below the stop; the difference is called the limit offset. Once triggered, the order fills only at the limit or better. If the price drops through the limit before the order fills, it stays open, unfilled, and the position stays open with it.
Some details depend on the broker. Firms differ on whether a last-sale price or a quote triggers the order, and many stop orders trigger only during regular trading hours. The NYSE stopped accepting stop orders on its own book in 2016, so the broker usually holds the order on its own system and sends a market or limit order once the trigger is met. The SEC's investor bulletin on stop, stop-limit and trailing stop orders and FINRA's guidance on stop orders in volatile markets both stress the same point: a stop price is not a guaranteed execution price.
How to read the difference
| Stop order | Stop-limit order | |
|---|---|---|
| After the trigger | Market order | Limit order |
| Guarantees | An exit, while the stock trades | A price, the limit or better |
| Overnight gap through the stop | Fills near the open, below the stop | No fill while the price stays below the limit |
| Brief drop that recovers | Can sell near the low | May fill partly or not at all |
| Main risk | Slippage beyond the planned loss | No exit; the loss is no longer capped |
The choice comes down to which failure is worse. For a protective stop, the purpose is to leave a trade whose idea has failed, so most traders accept slippage and use a stop order in liquid stocks. A stop-limit order suits cases where a poor fill is the larger risk, such as a thinly traded stock with a wide spread, provided there is a plan for the shares if it does not fill. For entries the logic often reverses: a buy stop-limit on a breakout prevents chasing a gap far above the planned buy point, and a missed entry costs nothing.
Worked example (illustrative numbers)
A trader holds 200 shares bought at $40.00 with a stop at $37.00, a planned loss of $600 (1R). The alternative is a stop-limit order with a stop of $37.00 and a limit of $36.80.
| Scenario | Stop order | Stop-limit $37.00 / $36.80 |
|---|---|---|
| Orderly decline through $37.00 | Fills about $36.98: loss about $604, 1.0R | Fills between $36.80 and $37.00: loss up to $640 |
| Earnings gap: opens at $34.00 | Fills near $34.00: loss $1,200, 2R | Not filled; if sold later at $32.00, loss $1,600, about 2.7R |
| Brief drop to $36.00, closes at $39.50 | Sold near the low; the stock recovers without the position | Some shares may fill at $36.80 or better; the rest stay open |
In the gap, the stop-limit order could also turn out better if the stock later rebounded above $36.80, but that depends on what happens next, which nobody knows when the order is placed. The stop order's loss was larger than planned, yet known within seconds of the open.
Limitations and common mistakes
- Treating the stop price as the exit price. Size positions knowing that a gap can produce a loss of 2R or more; see stop-loss and position sizing.
- No offset on a stop-limit. A limit equal to the stop rarely fills in a fast market. An offset of a fraction of ATR gives the order room.
- Forgetting an unfilled stop-limit. After a gap, decide in advance whether to exit at the open or wait; an open order that never fills is not a stop.
- Stops on obvious levels. Round numbers and exact swing lows collect orders; see stop-loss placement.
- Ignoring hours and duration. Know whether the order works in extended hours and whether it is a day order or good-till-cancelled, and when the broker cancels it.
- Assuming every broker offers both. Order types, trigger rules and trailing versions (see trailing stop) vary by firm.
In Clear Tape
Clear Tape never connects to a brokerage account and does not place orders. The free ATR stop calculator and position size calculator help set the stop and the size before the order is entered. In the free trade journal, the realized R of each trade is measured against the initial stop, so a stop that filled through a gap shows as a loss larger than −1R. Backtests in trading systems treat stops like stop orders: checked against each day's low, filled at the stop, or at the open when a session opens below it (Tools and Pro members).
For educational purposes only. Not investment advice.