Stop-loss orders are traditionally thought of as a way to prevent losses. However, another use of this tool is to lock in profits. In this case, sometimes stop-loss orders are referred to as a “trailing stop.” Here, the stop-loss order is set at a percentage level below the current market price (not the price at which you bought it). The price of the stop-loss adjusts as the stock price fluctuates. It’s important to keep in mind that if a stock goes up, you have an unrealized gain; you don’t have the cash in hand until you sell. Using a trailing stop allows you to let profits run, while, at the same time, guaranteeing at least some realized capital gain.
Continuing with our Microsoft example from above, suppose you set a trailing stop order for 10% below the current price, and the stock skyrockets to $30 within a month. Your trailing-stop order would then lock in at $27 per share ($30 – (10% x $30) = $27). Because this is the worst price you would receive, even if the stock takes an unexpected dip, you won’t be in the red. Of course, keep in mind the stop-loss order is still a market order—it simply stays dormant and is activated only when the trigger price is reached. So, the price your sale actually trades at may be slightly different than the specified trigger price.