* TSX down 12.77 points, or 0.08 percent, to 15,159.95
* Half of the TSX's 10 main groups were down
TORONTO, Sept 15 (Reuters) - Canada's main stock index were flat on Friday as declines in energy and mining stocks offset gains in other sectors, led by consumer discretionary and consumer staples companies.
At 10:26 a.m. ET (1426 GMT), the Toronto Stock Exchange's S&P/TSX composite index fell 12.77 points, or 0.08 percent, to 15,159.95.
Half of the index's 10 main groups retreated.
Together, energy and materials, which include mining and other resource firms, make up roughly a third of the index's weight. The energy group retreated 0.4 percent, though individual stock moves were more modest.
Wheaton Precious Metals Corp fell 1.5 percent to C$23.8, and Agnico Eagle Mines Ltd was down 1.0 percent to C$58.91. The two miners were among the most influential drags on the index, while the overall materials group lost 0.4 percent.
Metal prices were down, with bullion falling on global central bank prospects, while copper prices were on track for their biggest weekly fall since December, in part on profit-taking.
The heavily-weighted banks slipped 0.1 percent.
The Stars Group, formerly known as gaming company Amaya, saw shares jump 9.4 percent to C$23.32 after it raised its 2017 outlook and announced an additional debt prepayment. The broader consumer discretionary group rose 0.7 percent.
Consumer staples added 0.4 percent. Healthcare stocks advanced 0.5 percent.
Declining issues outnumbered advancing ones on the TSX by 135 to 104, for a 1.30-to-1 ratio on the downside. (Reporting by Solarina Ho; Editing by Nick Zieminski)