Smartphone manufacturer BlackBerry is preparing shed up to 40% of its work force by the end of this year. The layoffs will cut across all departments and occur in waves, likely affecting several thousand workers, US media reports said today citing sources. BlackBerry had 12,700 employees as of March, the last time it disclosed a total number. The job cuts come as the once dominant smartphone maker looks for ways to trim costs and shrink its operations match smartphone competitors like Apple and Samsung have taken a fair share of its market share. Two years ago, BlackBerry had more than 17,000 employees and 14% of the U.S. smartphone market. It now has less than 3% of the US market. Shares of BlackBerry Wednesday fell 2.2% (24 Canadian cents) to end regular trading at C$10.64 on the Toronto Stock Exchange.