I work for a finance company, and 1 of my jobs is to monitor fund performance.

every month our clients fund value is inputted on a sheet.

is there a way to

a) mark the highest value - being the Historical High for that clients funds.
and then
b) mark a new value if it falls 5% or more below the historical high?

I think the best way it would work for me is to change the colour of a value if it is either the historical high, or if it falls 5% below.

I hope i'm explaining myself ok - pointers in the right direction greatly received.