From 24/7 Wall Street:
The gut-wrenching drop back in August, when the Dow opened down 1,000 points and the indexes went through the first 10% correction in almost four years was, needless to say, an eye-opener for investors. If one looks at similar sell-offs over the past 20 years, a pattern appears: a sharp drop down, a 50% or so retracement and then a final drop to retest the initial lows.