Many are hesitant to invest in the stock market because of the large gaps in prices. It is not uncommon to see a stock that closed the previous session at $55 open the next trading day at $40. This kind of volatility can result in massive losses, but this is the risk that investors take when trying to make money in the stock market.
Regardless of the type of order placed, gaps are events that cannot be avoided. For example, assume you hold a long position in company XYZ. It is trading at $55, and you place a stop-loss order at $50. Your order will be entered once the price moves below $50, but this does not guarantee that you will be taken out at a price near $50. If XYZ's stock price gaps lower and opens at $40, your stop-loss order will turn into a market order and your position will be closed out near $40—rather than $50, like you had hoped. On the other hand, if you decided to enter a limit order to sell at $50 (instead of the stop-loss discussed above) and the stock opened the next day at $40, your limit order would not be filled and you would still hold the shares.
Mind the Gap
As you can see, if you are worried about a gap down in price, you may not want to rely on the standard stop-loss or limit order as protection. As an alternative, you can purchase a put option, which gives the purchaser the right but not the obligation to sell a specific number of shares at a predetermined strike price. Put options can be valuable when there is depreciation of the underlying stock price in relation to the strike price.
Holding a put option is a good strategy for traders who are worried about losses from large gaps because a put option guarantees that you will be able to close the position at a certain price. However, they do come with certain challenges, most specifically costs associated with long-term protection against gaps and the ever present issue of timing. Ultimately, though, put options are probably the surest way to mitigate gap risk, although it requires a level of sophistication and experience to get the timing right. (See also: The Basics of Order Entry, Understanding Order Execution and Options Basics.)