Another problem with a stop loss order is that when you enter it into the computer, the order is transparent. A game that some market-makers played (these days, it will be computer algorithms) is “run the stops,” when the stock is forced low enough to trigger a large cluster of stop loss orders (usually at round numbers or well-known support and resistance levels). After the stock is sold at a popular stop loss price, the stock reverses direction and rallies. http://www.marketwatch.com/story/why-i-stopped-using-stop-loss-orders-2013-05-09