On Wednesday's edition of Investor Beat, host Alison Southwick and Motley Fool analysts Taylor Muckerman and Jason Moser take investors through the biggest stories from the market today.

In this segment, Jason and Taylor explain why they're keeping close watch on shares of Facebook (META 1.69%) and Rio Tinto (RIO -1.46%). Should Facebook investors be concerned that Twitter (TWTR) has an edge in the all-important mobile advertising space?