Capture The Max and Min Values of Dynamically Changing RTD Data

[chacc]

I am using the excel RTD function to track the gain and loss in a stock portfolio using the thinkorswim RTD feed. This is dynamically data with the values constantly changing as they recalculate the actual gain/loss from the stock's quantity and price change every few seconds. I can not find a way to to store the max and min values.

It there a way to store the max and min values in a separate column as the RTD dynamic values change?