Carl Icahn reportedly building small position in Allergan, joining activist David Tepper

Carl Icahn is building a small stake in pharmaceutical company Allergan, Bloomberg reported Wednesday, citing sources.

The billionaire’s investment would come in addition to the 1 percent stake held by David Tepper’s Appaloosa Management. On Tuesday, Tepper said in a letter he is pushing the drugmaker to overhaul its management.

Shares of Allergan briefly rose 3 percent in after-hours trading.

“Allergan welcomes all investments in our company,” the firm said in a statement. “We maintain an active dialogue with our shareholders and value their constructive input and ideas on delivering long-term value.”

Icahn bought a big stake in Allergan in 2016 but sold out about a year later.

Read the full Bloomberg story here.