Exp. Share: Distributes XP to the whole team, even if not equipped (checked globally). the active Pokémon receives a split portion of the XP based on your team size. However, the Multi-Exp item grants a fixed 50% bonus to every inactive party member. This means Pokémon on the bench actually earn significantly more XP than the one fighting.
Also think to check in "Data" you've an option for EXP SHARE now ;)