Apple's Stocks app on iOS isn't terribly exciting, but in typical Apple fashion, it does have a bit more functionality lurking beneath the surface.
Pictured below is what you typically see when you fire up the Stocks app.
The information is pretty basic. We see that Apple's current share price is $456, and to the right of that in green we see how much Apple's share price has gone up for the day, in this case $3.98.
If you tap the green rectangle, however, the display changes to reveal Apple's current market cap.