Market Optimists Face Big Challenge

Stock markets are in the news again, thanks to their increasingly volatile behavior. Last week, the Dow Jones Industrial Average logged its largest single-day decline this year, a day after rising more than 250 points. The cumulative daily moves, in both directions, have exceeded 2,000 points so far this month, more than 10 percent of the value of the index. Overall, the trend has been down, eroding much of the gain investors had enjoyed this year.