You can use circular references to do this. If you want to track the
maximum value of cell A1 in cell D1, use

=IF(A1="",0,MAX(A1,D1))

If A1 is empty, the result is 0. For any other (numeric) value, D1
will be the largest number ever reached by A1. If A1 then drops in
value, the maximum will persist in D1.

You'll need to enable Iterative Calculations. On the Tools menu,
choose Options then the Calculation tab. There, check the Iteration
box.

For more info about persistent maximums and minimums, see
http://www.cpearson.com/Excel/PersistentMinMax.aspx


Cordially,
Chip Pearson
Microsoft MVP
Excel Product Group
Pearson Software Consulting, LLC
www.cpearson.com
(email on web site)


On Fri, 5 Dec 2008 12:21:01 -0800 (PST),
wrote:

I have a spreadsheet of a stock portfolio that updates in real time
according to performance. I want to be able to create a cell that
will cache the high of the day and the low of the day. I would
certainly assume I have to use macros to do so.

Basically I just have a net place where the net value of the equity
position updates intraday and I want to run the process and begin
caching the high and low for whatever time period.

Can anyone point me in the right direction to get started?