Snap Audience Reach Tracker: September 2017 -- Stifel
In slides accompanying research by Stifel, they note Facebook (FB) and Instagram are ahead of Snapchat in size of total audience, but Snap has leading reach within the 13-24 age demo in many top ad markets and is close to Facebook (46.7 mln vs. 47 mln) in the United States for this demographic. In all demographics in the United States, Facebook, Instagram, Instagram stories, and Snapchat, have total audiences of 225 mln, 107 mln, 70 mln, and 87.2 mln, respectively.