The Dow Jones Industrial Average just made history, highlighting the new level of turbulence stock investors face in whipsawing trading sessions. On Thursday, the blue-chip index ended with a gain or loss of at least 200 points for a sixth consecutive session--something the Dow has never done, according to Dow Jones data. The Dow DJIA, -1.84% ended Thursday's bumpy session up 369.26, or 2.3%, at 16,654.77--it's second day of gains since snapping a six-day losing streak Wednesday. Meanwhile, The S&P 500 SPX, -1.15% finished up 47.15 points, or 2.4% to 1,987.66, and the Nasdaq Composite Index COMP, -0.13% climbed 115.17 points, or 2.5%, to 4,812.71