TORONTO, Oct 25 (Reuters) - Canada's main stock index was down shortly after the open as Canadian National Railway CNR.TO fell more than 2.5 percent, and Roots Corp ROOT.TO opened 8 percent below its IPO price.
The Toronto Stock Exchange's S&P/TSX composite index .GSPTSE fell 37.69 points, or 0.24 percent, to 15,867.45.
Seven of the index's 10 key sectors lost ground.