Interesting article MrPaul but I think it contains a lot of flawed thinking. For a start it only contains one example. Obviously you'd need to see it repeated many times before drawing any conclusions. It also makes the mistake of thinking that just because one of these institutional indices are not going up this represents institutional selling but that isn't necessarily so. It just means some common stocks that are held by some institutions (as well as the general public) are underperforming compared to the S&P 500. I don't think you can jump to the conclusion from that that every time these institutional indices diverge from the S&P 500 then the market is about to crash.
That XII index contains all the DJIA stocks plus 45 others. For example while the DJIA only contains Coca-Cola, XII also contains Pepsi. I doubt it will prove as useful on a long-term basis as some here seem to be believe.
^XII: Components for AMEX INSTITUTIONAL INDEX - Yahoo! Finance