Investors Sell Off Stocks, Dow Plunges 512 PointsU.S. stock markets endured heavy losses on Thursday, with the Dow Jones Industrial Average suffering its worst one-day loss since late 2008, at the height of the financial crisis.SavePrintFrank Yu8/4/2011|Updated: 10/1/2015We had a problem loading this article. Please enable javascript or use a different browser. If the issue persists, please visit our help center.