Stock Market Power Rankings: Apple's $190 Billion Haircut

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.

Apple (NASDAQ: AAPL) remains the world's most valuable company, but life hasn't been easy for shareholders since the tech giant hit all-time highs early last month. Shares have fallen 17% off their peak levels, translating into a nearly $190 billion hit to the market cap.

It isn't helping that investors are rotating out of tech bellwethers, but Apple also didn't do itself any favors with last month's quarterly report. The market is concerned about sluggish iPhone sales, and things may not get any better in the near term. A couple of Apple suppliers over the past few days have been warning of weakness in the current quarter, leading some Wall Street pros to argue that Apple is slowing down production in light of waning demand.