Stocks plunge deeper into correction

The Dow Jones industrial average gained as many as 335 points (1.4%). The indexes later rolled over into the red and frequently swung between positive and negative territory. The Dow was headed for a 7.7% weekly decline, its worst in nine years. The Nasdaq joined the Dow and S&P 500 in a correction on Friday, defined as a 10% drop from the most recent highs.