* TSX down 66.66 points, or 0.42 percent, to 15,709.64
* Eight of the TSX's 10 main groups were negative
TORONTO, Oct 6 (Reuters) - Canada's main stock index fell on Friday as energy stocks, hurt by a sharp fall in oil prices, lead broad declines.
Suncor Energy Inc SU.TO and Canadian Natural Resources CNQ.TO were the most influential movers on the index. Suncor fell 0.8 percent to C$43.69, while Canadian Natural Resources declined 1.6 percent to C$41.34. Encana Corp ECA.TO dropped 2.4 percent to C$14.02.
The energy group slumped 1.4 percent after oil prices fell on profit-taking as well as renewed concerns about oversupply. Prices snapped a multi-week bull run, with U.S. crude CLc1 down 2.6 percent to $49.47 a barrel and Brent crude LCOc1 down 2.1 percent to $55.80. O/R
At 10:03 a.m. ET (1403 GMT), the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE fell 66.66 points, or 0.42 percent, to 15,709.64.
Of the index's 10 main groups, eight lost ground.
The heavily-weighted financials group slipped 0.2 percent, while industrials fell 0.4 percent.
Bombardier Inc BBDb.TO rose 0.7 percent to C$2.21. Reuters reported the plane and trainmaker spent $2.4 billion in the United States last year, tapping more than 800 suppliers in all but three U.S. states. The report shows the potential impact on the U.S. economy and companies if Bombardier's new CSeries jetliner is kept out of the U.S. market by a trade row with Boeing (NYSE:BA) Co. materials group, home to mining and other resource firms, lost 0.9 percent. Gold miners lost ground as bullion prices fell, with Goldcorp Inc G.TO shares down 1.4 percent at C$16.44.
Declining issues outnumbered advancing ones on the TSX by 185 to 55, for a 3.36-to-1 ratio on the downside.