Stop-Loss Order

A stop-loss order is one of the most widely used risk-management tools available to individual investors and active traders. When you place a stop-loss order, you designate a 'trigger price' — sometimes called the stop price — below the current market price. If the security's market price reaches or drops through that trigger, the order converts to a market order and is executed at the next available price.

The primary purpose of a stop-loss order is to cap the downside on any single trade or position without requiring constant monitoring. For example, if an investor purchases shares at $50 and sets a stop-loss order at $45, the maximum loss they are willing to tolerate before exiting the position is $5 per share, or 10 percent. Once triggered, the order is filled as quickly as possible, though during fast-moving markets the actual execution price can be materially different from the stop price — a phenomenon known as slippage.

There is an important distinction between a stop-loss order and a stop-limit order. A plain stop-loss converts to a market order upon triggering, guaranteeing execution but not price. A stop-limit order instead converts to a limit order, specifying both a trigger price and a minimum acceptable execution price. Stop-limit orders provide price certainty but carry the risk of going unfilled if the market gaps below the limit price.

In the United States, FINRA Rule 4210 and various exchange rules govern how these orders are handled by broker-dealers. Brokers are generally required to disclose their order-routing practices under SEC Regulation NMS. Not all brokers hold stop orders on their own books; many route them to exchanges or electronic communication networks (ECNs) where they reside until triggered.

Common strategies for setting the stop price include placing it below a key support level, below a moving average, or at a fixed percentage below the purchase price. Investors should be aware that very tight stops can result in being prematurely stopped out during normal intraday price volatility, while very wide stops may expose the portfolio to larger-than-intended losses. Regular review of stop placements as a position evolves is considered a prudent portfolio-management practice.