SPX (S & P 500) is Dominated By a Relatively Small Number Of Large Cap Stocks

SPX (S & P 500, http://bit.ly/i0nsT) is dominated/influenced by a relatively small number of large market capitalization stocks, see http://www.indexarb.com/indexComponentWtsSP500.html.

Less than 10% of SPX's (S & P 500, http://bit.ly/i0nsT) components influence slightly over half of the index's movements (47 of the 500 components influence slightly over half (50.11%) of the index's movements), and, of that less than 10%, the 20 largest market cap components influence 32.68% of SPX's (S & P 500, http://bit.ly/i0nsT) movements, see http://www.indexarb.com/indexComponentWtsSP500.html.

So, SPX (S & P 500, http://bit.ly/i0nsT) is hardly a good measure of the broad market's action, with the small cap Russell 2000 (RUT), see http://bit.ly/3QyXeD, being a much better gauge of the broad market's action.

The Russell 2000 (RUT) is also market cap weighted, but, much less so than SPX is, and, there are many more components obviously, see http://web.streetauthority.com/terms/index/russell2000.asp.

.......http://www.JoeFRocks.com/