The Dow Jones Industrial Average on Thursday extended the previous session's gut-wrenching downturn, with the blue-chip index off by more than 540 points and all three major equity benchmarks ending at fresh technical lows. The Dow DJIA, +0.19% closed down 545 points, or 2.1%, at 25,052, while the S&P 500 index SPX, +0.29% ended off 2.1% at 2,728, closing below its 200-day moving average for the first time since April, a day after marking its worst day session since Feb. 8, while the Nasdaq Composite Index also slipped further, off 1.3% at 7,329, edging further beneath its 200-day MA, viewed by technical analysts as a key dividing line between bullish and bearish momentum in an asset. Since Oct. 9, the 122-year-old stock benchmark has lost about 1,376 points, or about, according to FactSet data.