May 23 (Reuters) - Canada's main stock index edged lower on Wednesday as oil prices dipped on concerns that OPEC could increase crude output to make up for any shortfalls in supply from Iran and Venezuela. O/R
* At 9:50 a.m. ET (1350 GMT), the Toronto Stock Exchange's S&P/TSX Composite Index .GSPTSE was down 57.03 points, or 0.35 percent, at 16,087.76.
* Six of the index's 11 major sectors were lower, led by a 0.6 percent decline in energy sector .SPTTEN .
* Also weighing on the sentiment was the heavyweight financial sector .SPTTFS , which slipped 0.4 percent.
* Shares of Royal Bank of Canada RY.TO and Bank of Nova Scotia BNS.TO both dipped 0.5 percent and were the biggest drags on the financial index.
* The Canadian dollar weakened to a more than one-week low against its U.S. counterpart as the greenback broadly climbed. The materials sector .GSPTTMT , which includes precious and base metals miners and fertilizer companies, lost 0.4 percent as spot gold XAU= was down 0.15 percent at $1,288.92 an ounce. GOL/
* On the TSX, 109 issues were higher, while 136 issues declined for a 1.25-to-1 ratio to the downside, with 22.70 million shares traded.
* The largest percentage gainers on the TSX were Eldorado Gold ELD.TO , which jumped 5.0 percent, and Prometic Life Sciences PLI.TO , which rose 2.5 percent.
* Canopy Growth Corp WEED.TO fell 3.7 percent, the most on the TSX, followed by First Quantum Minerals FM.TO , down 3.2 percent.
* The most heavily traded shares by volume were Nemaska Lithium NMX.TO , down 17.0 percent after the lithium miner said on Tuesday it had secured funding of up to C$402 million ($314 million) from investors. Aurora Cannabis ACB.TO and Canopy Growth were also among the most heavily traded stocks.
* The TSX posted two new 52-week highs and one new low.
* Across all Canadian issues there were 10 new 52-week highs and 13 new lows, with total volume of 39.46 million shares.