Why is the stock market down today?

This morning’s trading showed the S&P 500 was down by 3.1%. Nearly everything on Wall Street is tumbling Monday as fear about a slowing U.S. economy worsens and sets off another sell-off for financial markets around the world.The S&P 500 was down by 3.1% in morning trading, coming off its worst week in more than three months. The Dow Jones Industrial Average was down 956 points, or 2.4%, as of 10:10 a.m. Eastern time, and the Nasdaq composite slid 4%.The drops were just the latest in a...