Sept 18 (Reuters) - Canada's main stock index looked set to snap a six-day winning streak on Wednesday, as the energy and materials sectors posted some of the biggest losses.
* At 9:36 a.m. ET (1336 GMT), the Toronto Stock Exchange's S&P/TSX Composite index was down 19.11 points, or 0.11%, at 16,815.64.
* Nine of the index's 11 major sectors were lower.
* The energy sector dropped 0.7% as oil prices extended their decline after Saudi Arabia said it would quickly restore full production following last weekend's attacks on its facilities.
* U.S. crude prices were down 1.7% a barrel, while Brent crude lost 1%.
* The materials sector, which includes precious and base metals miners, lost 0.6% as copper prices fell on Wednesday as concern about demand and economic growth dominated sentiment.
* Canada's annual inflation rate fell slightly in August on lower gasoline prices, Statistics Canada said on Wednesday in its first major data release since Canadian politicians formally hit the campaign trail.
* Trading environment also remained tepid as investors awaited an interest rate decision from the U.S. Federal Reserve.
* On the TSX, 80 issues were higher, while 141 issues declined for a 1.76-to-1 ratio to the downside, with 10.79 million shares traded.
* The largest percentage gainers on the TSX were shares of Interfor Corp, which climbed 2.7%, followed by shares of West Fraser, which rose 2.4%.
* CannTrust Holdings fell 6.5%, the most on the TSX, after regulator Health Canada suspended the company's license to produce and sell cannabis.
* The most heavily traded shares by volume were CannTrust, Crescent Point, and Encana Corp.
* The TSX posted three new 52-week highs and one new low.
* Across all Canadian issues there were 18 new 52-week highs and two new lows, with total volume of 16.49 million shares. (Reporting by Shreyashi Sanyal in Bengaluru; Editing by Shailesh Kuber)