TSX opens lower as energy, materials stocks drag

Canada's main stock index opened lower on Friday, reversing almost all of its weekly gains, as upbeat domestic retail sales data failed to offset the weakness in energy and materials stocks.

At 9:31 a.m. ET (1431 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 104.32 points, or 0.58%, at 17,811.88.