Stock Market Power Rankings: Down Is the New Up

Each week, I'm ranking the biggest companies that trade on U.S. exchanges based on their size ( market capitalization), momentum (total return over the past year), and recent news. Before we get to the rankings, a quick word on a major player.

The general market malaise has now bled into some of the world's most valuable companies. Just 3 of the 10 most valuable companies on U.S.-listed exchanges are now showing positive returns over the past year. It's a sharp contrast to when we started these weekly rankings in early November, with 7 of the 10 most valuable stocks by market cap in positive territory.

Microsoft (NASDAQ: MSFT), Amazon.com (NASDAQ: AMZN), and Berkshire Hathaway (NYSE: BRK-A) are the three giants that find their stocks trading higher than they were a year ago. Berkshire Hathaway is clinging to marginal gains, and that 1.5% gain can turn negative after another rough week of trading. Microsoft and Amazon are clinging to double-digit percentage gains. They remain the beneficiaries of the "flight to quality" mind-set in what is now a thinning pool of life preservers.