Former executives of the pharmaceutical giant are backing a push by activist investor Starboard Value to turn aro

Activist investor Starboard Value has taken a stake of about $1 billion in Pfizer Inc. and is seeking to spur a turnaround of the struggling pharmaceuticals giant, according to a person familiar with the matter.

Activist investor Starboard Value has taken a stake of about $1 billion in Pfizer and wants the U.S. drug giant to make changes to turn its performance around, sources familiar with the matter said on Sunday.