Activist investor Bill Ackman told CNBC he expected under-fire pharma company Valeant to take just weeks to sort out the issues hammering its share price.
Shares in Valeant Pharmaceuticals plunged more than 18 percent on Monday after the drugmaker revealed it faced a previously undisclosed Securities and Exchange Commission (SEC) investigation.
Valeant had said on Sunday night that it would delay releasing its fourth-quarter earnings, as well as withdrawing its financial guidance and admitting it would not be able to file its annual report to regulators on a form 10-K within a 15-day extension period.
The company also said that chief executive Michael Pearson - on medical leave since December - would return to work immediately.
Speaking exclusively to CNBC on Monday night, Ackman, whose Pershing Square fund holds a stake of about 9 percent in Valeant, said he had spoken to Pearson and was delighted that the CEO was back at work.
"We expect that much of the uncertainty will be resolved in the relative short term, hopefully over the next few or so weeks, when we expect the company to issue results, update guidance, and file its 10-K," the investor said.
"Based on publicly available information, it appears that Valeant's core franchises remain strong."
Ackman added, however, that the company needed to do a "much better job managing its public and investor relations, which the company has committed to strengthen."
Valeant is at the center of several ongoing investigations, including by the U.S. Attorney's Offices for Massachusetts and the Southern District of New York, the SEC and Congress.
Reuters reported that the SEC probe revealed on Monday was separate from an existging investigation into a company called Salix Pharmaceuticals, which Valeant had bought in 2015.
The revelations on Sunday and Monday were the latest in a series of hits to the company, which has attracted criticism for increases to its drug prices.
Late last year company opened a board investigation into Valeant's relationship with Philidor RX Services amid accusations it had used the specialty pharmacy to inflate revenues. Valeant is expected to restate its earnings as a result of that investigation.
Moody's Investors Service has placed the ratings of Valeant under review for downgrade, citing concerns that the company's operating performance is weaker than its expectations.
Shares in Valeant dropped as much as 21 percent in intraday trading before closing down 18.4 percent at $65.80.