Coloring Real Time Data

I have an API, which inputs real-time stock data into an excel book. Does anyone know how to make the Last Price cell change coloer (Greem=up, Red=donw) depending on whether the price moves up or down, relative to the last price?

ie, over the course of a minute a stock may price at 35.00 => 35.01 (cell turns green) => 35.00 (cell goes red) => 34.95 (cell stays red) => 34.97 (cell goes green).

VBA, conditional formatting, or any other means of doing this is perfectly acceptable.