May 8 (Reuters) - Canada's main stock index opened marginally lower on Wednesday, as gains in material and energy shares were more than offset by concerns about the outcome of U.S.-China trade talks.
At 9:30 a.m. ET (13:30 GMT), the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE was down 10.55 points, or 0.06 percent, at 16,347.2.