Tom DeMark, CEO of Market Studies, expects an 11.2-16.8% decline from here in the S&P. He created the DeMark Indicators which identify levels of trend exhaustion on charts. In the segment below, DeMark said the daily, weekly and monthly time series on the S&P 500 Index recorded a "13" or "major turning point" (exhaustive top).
He was on CNBC on 1/26/2011 predicting an 11% decline, but the unanticipated crisis in North Africa rebalanced the downside force (market gapped higher). In addition, only the daily and weekly time series had a 13 at that time. He believes the delay will just make the fall more intense. For technical confirmation, DeMark needed to see the March S&P Future close below 1326.30 ✓ and make a lower low tomorrow (today). He talked about the DAX as well.
|Combo Weekly Chart - Source: CNBC|
If you just look at the chart of the S&P, it looks like it could break through that uptrend from August 2010 and test the trend line from March 2009 (and pre-flash crash high). I put up the weekly chart below. The 50 week moving average (1171.58) is testing the 200 week MA (1179.53). SPX cash closed at 1315.
$SPX (S&P 500) - source: stockcharts.com