In plain language — A trailing stop moves its threshold when price travels in the favourable direction and does not move it back when price reverses. The threshold activates an order; it does not reserve a selling or buying price.
A trailing stop is a dynamic stop expressed as a fixed or percentage distance from a reference price. For a long position the threshold tends to rise with new highs; for a short position it tends to fall with new lows.
Distance, reference price, trigger rule, and child-order type depend on the broker or venue. Gaps and slippage can therefore separate the displayed threshold from the actual fill.
How the threshold updates
| Case | Favorable movement | Adverse movement | After the trigger |
|---|---|---|---|
| Exit from a long | A new reference high may raise the threshold | The threshold is not lowered | A sell order starts under the venue's rules |
| Exit from a short | A new reference low may lower the threshold | The threshold is not raised | A buy order starts under the venue's rules |
The distance may be expressed in points, currency, or percentage. Some platforms allow an initial activation price; others begin recalculating as soon as the order is accepted. Modification, cancellation, and time in force follow the specific contract.
Trailing stop and trailing stop-limit
- Trailing stop with a market order: after the trigger, it seeks execution at available prices. A fill may be likely in an open, liquid market, but its price is not guaranteed and can be affected by gaps or slippage.
- Trailing stop-limit: after the trigger, it submits a limit order. Price is constrained, but the order can fill only partially or remain entirely unfilled if the market moves through the limit.
The trigger rule may observe the last trade, a quote, the mark price, or another series defined by the venue. Trading hours, auctions, halts, tick size, and eligible instruments can also differ. The intermediary's documentation must be read; behavior cannot be inferred from the order's name alone.
Gap example
Consider a long at 100 with a 10% trail on a platform that uses the highest last-traded price. If the reference rises to 120, the threshold becomes 108. A sudden gap from 110 to 102 may activate a trailing stop with a market child, but the fill occurs at available prices, not necessarily at 108. A stop-limit version with a 108 limit could instead find no counterparty and leave the position open.
The example illustrates the mechanics; other venues may use different references, rounding, and event sequences.
Advanced: distance and checks
A tight distance reacts sooner but may be activated by brief fluctuations; a wide distance tolerates more adverse movement before the trigger. There is no universally correct percentage: the plan, observed volatility, holding horizon, liquidity, and maximum acceptable loss must be evaluated together.
Before submission, verify:
- trail reference and exact trigger condition;
- child order, distance, rounding, and any limit offset;
- eligible sessions, expiration, and treatment of gaps, halts, and missing data;
- quantity, side, and position coverage, including partial fills;
- order status and average price after activation.
Limit — A trailing stop does not guarantee profit, remove loss risk, or replace position sizing. It differs from a static take-profit and remains exposed to execution conditions.
Sources
- U.S. SEC, Investor.gov — Investor Bulletin: Understanding Order Types — defines trailing stops, distinguishes stop from stop-limit, and flags venue, trigger, and execution-price differences (accessed 10 August 2026).
- FINRA — Rule 5350: Stop Orders — documents stop and stop-limit activation and disclosure of alternative triggers used by an intermediary (accessed 10 August 2026).
- Interactive Brokers Campus — Trailing Stop Limit for Desktop — official example of one implementation using a trail, stop, limit offset, and possible lack of immediate execution (accessed 10 August 2026).
Links
- stop-loss — fixed stop, trigger, and execution risk.
- take-profit — static exit target and fills.
- volatility — amplitude and frequency of price movement.