The NDX dropped below the Sep 20 low of 14,821 on Tuesday, which puts us into the C wave of the decline from the record highs on Sep 7. From an Elliott Wave perspective, I think this correction is an Intermediate Wave IV. A strong support level would be 38.2% Fibonacci retracement of Wave III, which is 13,781.
What makes that an even stronger support level is that it is close to the target produced by a Fibonacci scenario in which Wave C of this correction equals 1.618 times Wave A. That downside target would be 13,932.
A milder downside target (Wave C = Wave A) would be 14,476, which is close to the July 19 low of 14,455.
Below is a chart for the Dow Industrials:
The Dow appears to be in a double zigzag as described in the previous post. If Wave Y equals Wave W, the target would be 33,043, a little below the June 18 low of 33,271.
For the S&P 500, I cannot find a long-term Elliott Wave count that make sense, but as for the current drop, if Wave C = Wave A, the target would be 4,225. If Wave C equals 1.618 times Wave A, the target would be 4,076.
The only scenario in which I could see the stock indices falling much below the targets in this post would be if the perceived likelihood of a government default were to increase. Right now, however, I think the chance of a default is very low.