U.S. stocks plunged on Monday in their worst day of Christmas Eve trading ever, as the S&P 500 entered a bear market. The Dow Jones Industrial Average dropped by 653 points Monday in volatile trading, falling below 22,000. The Dow sank more than 2 percent, then recovered nearly all of the day’s losses, before again falling more than 2 percent. The S&P 500 fell 2.7 percent, slipping into a bear market as it fell 20.06 percent from recent highs. Wall Street traditionally considers a drop of 20 percent or more from recent highs to be a bear market. The Nasdaq Composite Index slid 2.2 percent. Markets responded to ... (full story)