I've done a couple of posts in the past on "Mr. Fat Finger"...one on April 21, 2011, and the other on December 3, 2011. The following is a brief update.
There are two shaded circles on each of the Weekly charts below of YM, ES, NQ & TF. The first contains the infamous "Fat Finger" day in 2010. The second contains the downdraft following Standard & Poor's downgrade of the U.S. credit rating in 2011. For all you wave traders, we may be approaching the final segment of a Wave 5 on the Weekly timeframe. It may be prudent to be prepared for sudden "Fat Finger" downdrafts, particularly if the TF is not able to break out and hold above 2011 highs.
In this regard, the support levels, which coincide with the upper portion of the 2011 downdraft, are 12500 for YM, 1330 for ES, 2420 for NQ...850 represents that level for TF, but it hasn't even closed above it yet, so it's holding as resistance.
On a smaller 4-Hour timeframe, the charts below contain an uptrending channel from December 2011 lows. They show the YM as the weakest after the 2-day pullback, so far, this week, then ES, TF, and NQ.
The last 4-Hour charts below contain an External Fibonacci retracement. We could get a bounce here if the YM holds above the confluence of the 38.2% retracement and the lower channel. The NQ retested its Fibonacci breakout and bounced at the 100% External Fibonacci level after reaching its 200% External Fibonacci level...it's back inside the channel.
In summary, the important players are YM and NQ on a 4-Hour timeframe, as well as the TF on a Weekly basis...ones to watch for potential further weakness.