Is there a general formula or methodology that would allow me to compare my entire portfolio to the wider S&P; such that if the Index drops x%, my portfolio would be expected to drop Y% and vice versa. I want to understand the sensitivity of my OVERALL portfolio is the an index. Could I use a weighted average of Beta for each against 1.0 for the index? Maybe R-sqrd?

Perhaps I'm asking the impossible? Thanks for any input.

dab1477