Concordia International Chief Executive Mark Thompson has been forced to sell 505,000 shares in his company due to a margin call. 

The Oakville, Ont.-based specialty pharmaceutical firm says the shares were used by Thompson to secure loans and were sold after the stock fell below an unspecified threshold. Concordia's stock (CXR.TO) has plunged 79 per cent this year. 

“It is with great regret that I have been forced to sell shares in Concordia,” Thompson said in a statement late Monday. “This is no way diminishes my confidence in Concordia’s business and prospects.” 

The sale leaves him with 1.6 million shares.    

Concordia has largely relied on a debt-fueled acquisition binge for growth. Like Valeant Pharmaceuticals Inc., Concordia’s once-hot stock has plummeted amid questions about its drug pricing strategies. Short sellers have circled the company in what Thompson has called “an unrelenting and unscrupulous attack.” 

In an interview with BNN, Norman Levine, managing director at Portfolio Management Corp., called Thompson’s use of Concordia shares to secure loans “wrong.”

“When [the shares are purchased] on margin they have to pay interest; they have to worry about what the share price is doing. That bothers me,” Levine said.

“I like it when companies are run by chief executives who say we have to get companies operating the best they can and the share price will take care of itself.”