Stocks plummeted in the opening minutes of trading Wednesday as a deepening pessimism about the economy and corporate earnings swept across Wall Street.

Within the first 15 minutes, the Dow Jones industrial average tumbled more than 330 points to fall below the psychologically important 10,000 level for the first time since October to about 9,960 . The drop wiped out the average's 82-point gain Tuesday and compounded a 436-point slide on Monday. 

The Nasdaq composite index bounced down nearly 80 points, then picked up a little to be down only 68 to 1,945. 

The S&P 500 dropped 35 points to 1,162, while the broader Wilshire 5000 fell 311 to 10,703.