(Reuters) - Canada's main stock index opened flat on Friday in thin trading volumes, while investors assessed gross domestic product data that reinforced expectations of the Bank of Canada implementing an interest-rate cut next month.

At 9:31 a.m. ET (1431 GMT), the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE was down 10.68 points, or 0.04%, at 25,532.84.