By Ross Marowits, The Canadian Press

Montreal: Valeant Pharmaceuticals, once one of Canada’s most valuable companies, saw its shares lose more than $15 billion of their value Tuesday after reporting disappointing earnings, lowering its outlook for 2016 and raising fears about defaulting on its debt.

Stock in the Quebec-based drug giant shed nearly 51 per cent, closing at C$45.14 on the Toronto Stock Exchange, its lowest level since November 2011. At its peak close last August, Valeant stock was worth C$346.32.

“Our business is not operating on all cylinders,” CEO Michael Pearson said in a conference call. “But we and I are committed to get it back on track.”

The company said it had a net loss of US$336.4 million in the final quarter of 2015 _ rather than a net profit of US$462.6 million as analysts had expected, largely due to costs associated with restructuring and acquisitions.

After adjustments, Valeant says it earned US$875.7 million or $2.50 per share. Analysts had estimated adjusted earnings of US$942.8 million, or $2.61 per share, according to Thomson Reuters.

Valeant’s revenue for the fourth quarter was just under US$2.8 billion, which was in line with analyst estimates, but the company reduced its previous sales and adjusted earnings estimates for the first quarter of 2016.

“In a sense, we’ve botched a quarter,” Pearson said.

There could be more bad news on the horizon.

The drugmaker has delayed filing its 2015 annual report with regulators while it investigates its former relationship with Philidor. Questions arose last October after a report revealed Valeant’s previously undisclosed relationship with the Pennsylvania mail-order pharmacy. Valeant has since launched an internal investigation into the matter.

The company risks defaulting on its debt if the 2015 annual report is not filed by April 29. Pearson said he hopes to file the report next month but is negotiating an extension.

Uncertainty about the potential for a default creates “enormous investor fear,” said Bill Ackman of Pershing Square Capital Management, one of Valeant’s largest shareholders who also sits on its board of directors.

In a note to clients, the hedge fund manager said he plans to take a more proactive role to protect its investment and restore confidence in the company’s management and governance.

Last month, Valeant announced that it had to restate its financial results for 2014 and 2015 after finding that about US$58 million of sales to Philidor were recognized at the wrong time.

Its efforts to regain confidence may have taken a hit Tuesday when it overstated its forecast of adjusted pre-tax operating earnings before interest, taxes, depreciation and amortization over the next four quarters. Valeant later issued a corrected news release.

Pearson said he accepts responsibility for Valeant’s poor performance and miscommunication about its strategy.

“We have to earn back the credibility,” he said. “It’s a bit of a starting-over point at this point for me and the company and clearly if we don’t deliver, then that’s on me.”

Although Pearson said Valeant is tough company to work for these days, executive vice-president Anne Whitaker said employee morale was good.

“Actually, they’re angry more at the outside because they see the company being described in a way they know is not what they experience at Valeant,” she said on the call.

Valeant is facing allegations of drug-price gouging, accusations it has denied. It is also under investigation by the U.S. Securities and Exchange Commission, U.S. Attorney’s offices in Massachusetts and New York, as well as Congress, as part of their probes into price hikes for certain drugs.

Pearson said the company plans to cut costs and sell non-core assets, warning that additional steps may be required if it doesn’t deliver promised cash flows to repay debt.