"Stephen POWELL" wrote in message
...
Matthew:
A not very sophisticated approach would be to add a helper column to the
right of your monthly returns which calculates the cumulative return from
the
first month.
Step 2 would be to use a vlookup that takes the cumulative value found by
using your later date and divides it by the result of a second vlookup
that
returns the cumulative value found by using your earlier date and then
subtracts 1.
Stephen Powell


I think this is a reasonable approach.

/Fredrik