What is a Stop-Loss Order?
A stop-loss order is a broker instruction that automatically sells a security when its price drops to a level you set in advance, capping your downside without requiring you to watch the market constantly.
A stop-loss order is an order placed with a brokerage to sell a security automatically if its price falls to or below a specified level — called the stop price. It's designed to limit the amount you can lose on a position without requiring you to actively monitor it.
Stop-loss orders are one of the most commonly used risk management tools for individual investors and traders. They take emotion out of the exit decision: instead of hesitating when a position moves against you, the order executes automatically.
How a Stop-Loss Order Works
When you place a stop-loss order, you set a price threshold. If the security's price touches or falls below that threshold, your broker submits a market order to sell at the best available price.
Example: You buy a stock at $50. You set a stop-loss at $44 (a 12% drop). If the price falls to $44, your broker automatically sells — you exit the position with a loss capped at approximately 12%.
The key word is approximately. In fast-moving or illiquid markets, the actual sale price may be worse than your stop price — a phenomenon called slippage. During extreme volatility, a stock can gap down significantly below your stop price before the order triggers.
Stop-Loss vs. Stop-Limit Orders
A related order type, the stop-limit order, addresses the slippage risk of a standard stop-loss — but with a trade-off:
| Stop-Loss Order | Stop-Limit Order | |
|---|---|---|
| Triggers at | Stop price | Stop price |
| Executes as | Market order | Limit order at or above the limit price |
| Guarantees execution | Yes (at market price) | No (may not fill if price moves past limit) |
| Slippage risk | Yes | Minimal |
| Risk of no fill | No | Yes |
A stop-limit order gives you price control but can leave you holding a falling position if the price drops past your limit before the order fills.
How to Set a Stop-Loss Level
There's no universal rule for stop placement — it depends on your strategy, the stock's volatility, and your risk tolerance. Common approaches include:
- Percentage-based: Set the stop at a fixed percentage below your entry price (e.g., 8–10%)
- Technical levels: Place the stop just below a key support level, moving average, or recent swing low
- ATR-based: Use the stock's Average True Range (a volatility measure) to set a stop that reflects normal price movement, not random noise
- Dollar amount: Set the stop at the maximum dollar loss you're willing to accept on the position
The goal is to place the stop close enough to matter, but far enough to avoid being triggered by normal day-to-day price fluctuation.
Trailing Stop-Loss Orders
A trailing stop is a dynamic version of the stop-loss that moves up automatically as the stock rises, locking in gains while still providing downside protection.
Example: You buy at $50 and set a 10% trailing stop. The stop is initially at $45. If the stock climbs to $70, the stop moves up to $63. If the price then falls to $63, the order triggers — you've locked in most of the gain without having to manually adjust the stop.
Limitations and Risks
- Gaps and after-hours moves — Stop-loss orders don't protect against earnings gaps or news events that occur outside of market hours. A stock can open 20% lower the next morning, well below your stop.
- Stop hunting — In some volatile markets, prices briefly dip to take out stop-loss clusters before reversing — a pattern some traders call stop hunting. Your stop triggers and you sell at the low, only to watch the stock recover.
- Not suitable for long-term investors — If you hold a diversified portfolio for the long term, stop-losses can trigger unnecessary sales during temporary market volatility, generating taxes and locking in losses that would have recovered.
Who Should Use Stop-Loss Orders
Stop-loss orders are most useful for:
- Active traders who hold individual stock positions with a defined risk-reward framework
- Investors with concentrated positions in a single stock who want protection against catastrophic loss
- Anyone who can't monitor positions daily and wants automated downside protection
For long-term index fund investors with diversified portfolios, stop-loss orders are generally unnecessary — and can actually work against you by converting a temporary drawdown into a permanent realized loss.