Key Takeaways Pfizer shares have gained ground since a report over the weekend said that activist investor Starboard Value has taken a roughly $1 billion stake in the drug maker and is pushing for changes.

Starboard has approached two former Pfizer executives, Ian Read and Frank D’Amelio, to assist in its efforts, and they have expressed interest in helping, The Wall Street Journal reported Sunday, citing people 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.