Investors should stay on guard heading into what could be a choppy fall.Drew Angerer/Getty Images Markets have been unusually volatile in recent weeks due to conflicting economic data. Bank of America is optimistic about the economy, but it's less bullish about US stocks. Here are 14 companies that have consistently dominated for a decade. A wild month in markets has muddled the investing landscape ahead of what promises to be a turbulent autumn.Mixed signals abound after the S&P 500 followed a 6.1% sell-off in the first three days of August with an equally astounding 8.1% rally, resulting in a modest monthly gain.