TL;DR: A trailing stop order sets a stop that moves. With an illustrative 10 percent trail, a stock at $100 starts with a stop at $90, since $100 multiplied by 0.90 equals $90. If the price rises to $120, the stop rises to $108, since $120 multiplied by 0.90 equals $108. If the price then falls, the stop stays at $108, and a fall to $108 triggers a sale. The mechanism locks in a give back limit without fixing a single exit price in advance, but ordinary pullbacks can trigger it, and once triggered it usually becomes a market order, so the fill is not guaranteed to be $108.
Key Takeaways
- The stop is defined by distance from the peak, not by a fixed price: a percentage or a cash amount below the highest price reached since the order was placed.
- It only moves in one direction for a sell order: up when the price makes a new high, never down when the price falls.
- Triggering does not guarantee the trigger price. Most trailing stops convert to market orders, so gaps can fill below the stop.
- Trail width is the whole decision: too tight and normal movement exits you, too wide and the protection arrives late.
Work the ratchet step by step
All figures in this section are illustrative. You buy at $95 and place a trailing stop of 10 percent. For simplicity, follow the stop from round prices. When the price is $100, the stop is $100 multiplied by 0.90, which equals $90. The price rises to $120. Because $120 is a new high, the stop ratchets up to $120 multiplied by 0.90, which equals $108. The price rises again to $130, and the stop follows to $130 multiplied by 0.90, which equals $117.
Now the price falls to $125. Nothing changes: the stop is calculated from the highest price, $130, so it stays at $117. If the price falls to $117, the stop triggers. Suppose it fills at $117 for an investor holding 100 shares bought at $95. The gain per share is $117 minus $95, which equals $22, and the total gain is $22 multiplied by 100, which equals $2,200. That is an illustrative fill at the trigger price: a real fill in a fast fall or an overnight gap could be lower, because the triggered order seeks the available market price.
Notice what the trail did across the example. At the $100 mark, the investor was willing to give back $10 from the peak, since $100 minus $90 equals $10. At the $130 peak, the give back allowance had grown in cash terms to $13, since $130 minus $117 equals $13, while staying at the same 10 percent. A percentage trail widens in dollars as the price rises. A fixed cash trail, for example always $10 below the peak, would behave in the opposite way, becoming proportionally tighter. Choosing between them is choosing how the protection changes as a position grows.
How is a trailing stop different from a stop loss and a stop limit?
A fixed stop loss order never moves: if the price doubles, the original stop sits far below, protecting little of the gain. A trailing stop moves with new highs, which is its entire purpose, converting paper gains into a defined maximum trigger distance. The distance is defined; the eventual fill is not, because a triggered stop usually becomes a market order and slippage can carry the fill past the stop price. A stop limit order controls the execution price once triggered but can go unfilled. A standard trailing stop does not control the execution price: it prioritises getting out once the give back limit is reached.
Trailing stops are also used by buyers in reverse: a buy side trailing stop sits above the lowest price seen since the order was placed and steps down as the price makes new lows, triggering a purchase if the price rebounds a set distance off its low. The sell side protection use is the common one, and it is the use this explainer works through.
Setting the trail width honestly
The trail has to be wider than the normal movement of the specific stock, or the order is really a delayed sale at a random point in ordinary noise. A calm, large company stock and a volatile small stock need very different trails for the same intent, and a trail copied from another position imports the wrong assumption. This is a risk framing decision like those in position sizing explained: the numbers should come from the behaviour of the asset you actually hold and the give back you can genuinely accept, reviewed when either changes.
Broker implementations differ in important details: whether the trail follows intraday highs or closing prices, whether it is active outside market hours, and whether a trailing stop limit variant is offered. Read your broker's order documentation for the exact behaviour before relying on it, because two orders with the same name can trigger differently.
This article is educational information about how a trailing stop order works, not financial advice. Prices in the worked example are illustrative and are not the price of any real security.
The same moving stop appears as a risk tool in short selling explained, where a rising price is the loss direction instead. For a fixed two price version, see what is a stop limit order.
Sources and method
- Target keyword: "what is a trailing stop order" from .saeo/keywords.yaml (queue entry added 2026-10-30). No search volume or difficulty figure is claimed; both are recorded as unknown in the queue entry.
- All figures are labelled illustrative examples. Arithmetic verified for this draft on 2026-10-30: $100 multiplied by 0.90 equals $90; $120 multiplied by 0.90 equals $108; $130 multiplied by 0.90 equals $117; $117 minus $95 equals $22; $22 multiplied by 100 equals $2,200; $100 minus $90 equals $10; $130 minus $117 equals $13.
- Internal links checked against existing drafts in this folder on 2026-10-30: what-is-a-stop-loss-order, what-is-a-stop-limit-order, position-sizing-explained.
- Distinction check: what-is-a-stop-loss-order covers a fixed trigger. This draft covers the moving trigger and its one way ratchet only.
