How to identify a period of defined monthly performance

[decentdoobs]

Hi Everyone,

I'm using Excel 2007 on Windows 7

I'm not sure how to best describe this with the appropriate terminology. I appreciate the patience of you experts.

I have a range of monthly performance for a benchmark and my portfolio.

I am looking to identify periods where I can set the parameter (such as declines of -10% or more) and compare how a portfolio did vs the benchmark at that identified time period.

For Example, if I set the parameter/constraint to -10% or the formula will identify the beginning/ending month of the period that the benchmark had a 10% or more decline.

Then I will use that range to calculate the return.

I appreciate any assistance. Please let me know if I can clarify in any way.

Thank you!