(Adds details on disclosure)
Nov 23 (Reuters) - Activist investor Bill Ackman's hedge fund has significantly increased its investment in Valeant Pharmaceuticals International, and signaled it may play a greater role in the beleaguered drugmaker's strategy, according to a regulatory filing.
Ackman's Pershing Square Capital Management raised its stake in Valeant to 9.9 percent from 5.7 percent reported in March, according to a filing on Monday with the U.S. Securities and Exchange Commission. (1.usa.gov/1LwwmGG) Shares in the company rose 3.1 percent in after-hours trading.
Pershing noted in its filing that it may conduct discussions with Valeant management, other shareholders and relevant parties "including other companies in (Valeant's) industry" about the drugmaker's strategic plans and other matters. The language about contacting other drugmakers did not appear in its first ownership filing in March.
The disclosure comes at a time of heightened speculation about the future of Valeant, which is under scrutiny for steep price hikes on its drugs to boost profits and for its close ties to a specialty pharmacy that used aggressive tactics to get insurers to reimburse the cost of its medicines.
Some key Valeant investors have questioned whether Chief Executive Michael Pearson should step down. Ackman earlier this month expressed confidence in Pearson's leadership. People familiar with Ackman's thinking have said the billionaire is open to considering alternatives for Valeant's future, including a sale.
"You are one of the most shareholder-oriented CEOs I know," Ackman wrote to Pearson in an email seen by Reuters. "You have assured me that you and the rest of the board are considering any and all alternatives that would benefit shareholders and other stakeholders."
For the past few months, Valeant shares have seen steep losses, declining in value from more than $260 per share in August to a low of $69.34 last week.
The losses were initially triggered by a critique of rising drug prices from presidential candidate Hillary Clinton in late September, and then accelerated when short sellers raised questions about Valeant's relationship with specialty pharmacy Philidor Rx Services last month.
Ackman last year teamed up with Valeant in a failed attempt to acquire rival drugmaker Allergan. (Reporting by Carl O'Donnell in New York, Svea Herbst-Bayliss in Boston and Shailesh Kuber in Bengaluru; Editing by Anil D'Silva, Michele Gershberg and Tom Brown)