Shares of Dollarama Inc. (DOL.TO) fell in early trading Wednesday after an American activist investor took aim at the Canadian retailer.

"After our Canadian successes ... we are pleased to issue a ‘Strong Sell’ report on Dollarama," New York-based Spruce Point Capital Management announced in a tweet. 

In another tweet, Spruce Point labeled Dollarama a "broken growth discount retailer" and warned its stock could fall at least 40 per cent. 

"As competition increases, customers push back against recent price hikes, and operating costs creep upwards, we believe that management will have a difficult time maintaining current profitability levels," Spruce Point said in a 53-slide presentation published on its website.

Shares of Dollarama fell as much as 7.7 per cent in early Wednesday trading on the Toronto Stock Exchange.

The Montreal-based company enjoyed many years as a stock market darling since going public in 2009. But after it shares skyrocketed more than 1,600 per cent from October 2009 to the end of last year, its stock has come under pressure, tumbling 32 per cent so far in 2018.

In an emailed statement to BNN Bloomberg, a Dollarama spokesperson said the retailer is "confident our existing disclosure provides our investors with accurate, up-to-date and comprehensive information regarding the company, its performance, as well as its relevant governance, accounting and other policies."