Moan. Here we go again. Yesterday's big gain was largely erased at the opening bell today—and was pretty much entirely erased by 11am EST—over fears about the global economy. The Dow fell as much as 446 points, and is currently down around 400 points. Nasdaq and the S&P 500 have sunk about 3% each, down about 74 and 37 points, respectively, reports MarketWatch, which notes that gold has topped $1,800 an ounce. (More Wall Street stories.)