The likely collapse of the so-called supercommittee's efforts to put together a deficit-reduction deal and continued concern about the debt crisis in Europe are pushing stocks lower on Wall Street.
At midday, the Dow Jones industrial average is down about 300 points (2.6 percent). Other major indices are also down at least 2.25 percent.
"You're looking at a potential double whammy," Barry Knapp, the New York-based head of U.S. equity strategy at Barclays Plc, tells Bloomberg News. "The bigger problem is that a deal in the supercommittee was expected to pave the way to extend the stimulus that is in the system. If you don't get a deal, which is probable, you get a big hit to the economy in the first quarter right at the point when the economic fallout from the European debt crisis is hitting."
Update at 4:37 p.m. ET. Closing:
At close the Dow ended 2.11 percent down; Nasdaq 1.92 percent down and the S&P was 1.86 percent down.