The small-cap Russell 2000 fell 1.4 percent to 1,085, and is now in official correction territory–10 percent off its July high.
"The Russell has been a head wind and now is comfortably below the 200-day which is never a good sign and it's 10 percent off its highs," Redler said.
Redler said 1,927 would be a test, and he does not see the S&P falling below the 1,900 to 1,927 range. "The 150-day is the moving average that held in the first down move that started this year in January," he said.
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Recent volatility has spooked traders in part because from a seasonal standpoint, October is often a volatile month. But when there's a sell off, there's often been a turn around that also started in October. Bespoke, in a report, said that there have been 12 times since 1928 that the S&P 500 fell more than 1 percent on Oct. 1. All but two times, the index moved higher on the next trading day, for an average gain of 0.9 percent. In those same years, for the month of October, the index was up 8 of 12 times, with an average gain of 3.8 percent.
Markets reacted strongly Wednesday to disappointing PMIs both in Britain and Germany, which saw contraction. In the U.S., the ISM manufacturing index fell to 56.6 from August's 59 level–still well in the zone signaling growth.
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"It speaks to a good manufacturing climate but not great. It does not speak to an environment where the Fed has to move faster though you're going to get a more buoyant bond market," said Adrian Miller, director of fixed-income strategy at GMP Securities.
Miller said Draghi has hoped to expand the ECB's asset purchase program to include different types of credits, because there is not as much liquidity in asset-backed securities in Europe.
"Will he be able to reach for more, lower quality ABS in order to broaden the program enough to increase the efficacy of getting the money into the real economy?" Miller asked. "That coupled with the mediocre TLTRO (targeted long-term refinancing operation) is going to call into credibility what the ECB can deliver."
Bond prices also moved higher and yields fell as investors reacted to the first case of a patient coming down with Ebola in the U.S.