Stocks plunged sharply Thursday, with the Dow down more than 500 points, in its worst one-day drop since December 2008.

All three major averages tumbled into negative territory for the year as investors were rattled over an intensifying global economic slowdown and ahead of the widely-followed monthly unemployment report.

The Dow Jones Industrial Average plummeted 512.76 points, or 4.31 percent, to close at 11,383.68, led by Alcoa and BofA . The last time the Dow dropped more than 500 points in a single session was in Dec. 2008.

The S&P 500 sank 60.27 points, or 4.78 percent, to end at 1,200.07.

The Nasdaq plunged 136.68 points, or 5.08 percent, to finish at 2556.39.

The major indexes are firmly in negative territory for the year. In addition, all three averages fell into "correction territory," defined by a drop of 10 percent from its peak from its intraday high in Apr. 29.