7 reasons why the stock market is very volatile

NEW YORK - Plunge! Rebound! Crash! Rally! Plunge again! Its been a sad story line of the stock market the last five trading days, the piteous, confidence-testing, destroying wealth volatility attack that has put investors on edge.

Wall Street has been broken again, just as happened in 2008, when stock prices swing sharply up and down like an elevator in a skyscraper during the busy morning. Just as happened on May 6, 2010 when a "flash crash" inspired by a short dive the Dow nearly 1,000 points. And as happened on Black Monday in October 1987, when the Dow suffered record one-day percentage drop 22.6%.