Noted activist investor David Tepper's hedge fund Appaloosa Management has received Federal Trade Commission antitrust clearance to increase its stake in Allergan.
Investors have been unhappy with Allergan's stock performance over the last year, and some would like to see the pharma company explore splitting up.
Allergan shares closed up 3% on Thursday.
Allergan investors have been pushing the company privately to consider making big changes. Now another big investor may be joining the...