[isatrader]

interestingly that although the market reversed hard yesterday the bpnya hardly fell at all..

That's partly because of the nature of how P&F charts are calculated in that they can only move once per day. i.e. yesterday had a strong open and so a lot of stocks would have added an additional X if they were already in a column of Xs, even if they later reversed lower, as they can only make one move per day.

The $BPNYA is a compilation of the percent of stocks that trade on the NYSE that are on Point and Figure buy signals and tells you whether to be offensive or defensive with your strategy. And it also takes a lot to move the NYSE Bullish Percent Index because of the large amount of stocks in it, which is why it's used as a long term gauge of risk and not a so much as a timing measure.