Complex sentence: Due to Riggio's involvement, GameStop and Barnes & Noble employees still received employee discounts at each other's stores, despite the companies being completely separate; both companies chose to terminate this arrangement on September 1,2010.
Split into simpler sentences: Due to Riggio's involvement, GameStop and Barnes & Noble employees still received employee discounts at each other's stores, despite the companies being completely separate. Both companies chose to terminate this employee discount arrangement on September 1,2010.