The previous link was for the Nasdaq McClellan Oscillator Ratio Adjusted with the SPX overlaid. Here is the link for the NYSE McClellan Oscillator Ratio Adjusted. Same thing overall as both NDX and SPX basically travel in the same direction. And note the points where the Bollinger Bands are violated on the lower band at SPX price lows (red dotted line). The lower Bollinger Band punctures which are circled match up with price lows of the SPX (red dotted line). But like most indicators that catch price lows the magnitude and duration of the rally after vary dramatically. The summer of 2011 had extreme volatility so I included that time on this chart. There were two signals in that volatile time frame with this as well that worked out much like the ones after.