Activist investor ValueAct Capital Management upped its stake in Valeant Pharmaceuticals, sending shares 4 percent higher in after-hours trade Thursday.
In a Thursday filing with the Securities and Exchange Commission, the hedge fund reported that it bought 3 million shares on Tuesday, increasing its stake to about 5.2 percent.
During Tuesday's session, Valeant shares hit a 52-week low of $10.50.
ValueAct purchased 500,000 shares at $10.88 each and another 2.5 million at $10.81 each, according to the filing.
ValueAct said in its Thursday filing that it bought the shares based on its "belief that the securities were undervalued and represented an attractive investment opportunity." The hedge fund said it intends to continue discussions with Valeant "to discuss ways to enhance shareholder value."
Robert Hale, a partner at ValueAct, serves on the board of Valeant.
Before the Thursday filing, ValueAct was already the second largest holder of Valeant, according to FactSet.