A 5 percent move in futures doubles your money. With stocks, you must put up 50 percent margin, so you need a 50 percent move to double your money (which, due to inflation and growth, is generally easier to do in bull markets. Fortunately, markets move down faster than they move up, even if, in percentage terms, stocks tend to go up farther than they move down. "A good general never risks all of his troops in the front line at one time." Disclaimer. This has been printed without permission.