TORONTO - Shares in Canada's biggest pharmaceutical company lost almost 20 per cent yesterday to close at $154.21.

The loss happened after a report accused Laval-based Valeant of creating a network of phantom pharmacies to deceive auditors.

At one point yesterday, Valeant shares were down almost 40 per cent before gaining some strength.

Valeant staunchly denies the report by Citron Research, a short-seller's research firm that examines fraudulent and over-hyped stocks.

A Valeant spokeswoman says Citron's "false and misleading statements" appear to be aimed at manipulating the market in an effort to put downward pressure on the company's shares.