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?